JP2005012858A - LOAD DRIVE DEVICE, AUTOMOBILE MOUNTED WITH THE LOAD DRIVE DEVICE, AND COMPUTER-READABLE RECORDING MEDIUM RECORDING PROGRAM FOR CAUSING COMPUTER TO EXECUTE CONTROL IN EARTH - Google Patents

Abstract

Provided is a load driving device capable of taking appropriate leakage countermeasures in an electric system including a boost converter.
A load driving device includes a DC power supply, a boost converter, an inverter, a control device, and a leakage detector. The leakage detector 70 outputs a signal DEL to the control device 30 when detecting leakage in the alternating current section of the load driving device 100. When controller 30 receives signal DEL, controller 30 determines whether boost converter 11 is performing a boost operation based on torque command value TR and motor rotational speed MRN. Control device 30 outputs signal PWML to boost converter 11 when boost converter 11 is performing the boost operation, and controls boost converter 11 to perform the step-down operation. Boost converter 11 steps down DC voltage Vm on the side of inverter 20 in accordance with signal PWML and supplies it to DC power supply B1.
[Selection] Figure 1

Description

【０１３３】
となる。
そうすると、電圧Ｖｎは、
【０１３４】
【数２】

【０１３５】
となる。
その結果、電圧Ｖｎは、電圧Ｖの周波数ｆが高くなれば低くなり、周波数ｆが低くなれば高くなる。つまり、電圧Ｖｎは、電圧Ｖの周波数ｆの変動に伴って変化する。このことは、判定回路６１３が波高値抽出回路６１０〜６１２から受ける波高値Ｈ１〜Ｈ３が周波数の変動に伴って変化することに相当する。したがって、判定回路６１３は、波高値抽出回路６１０〜６１２から受けた波高値Ｈ１〜Ｈ３が変動していれば交流部において漏電が発生していると判定する。
【０１３６】
また、交流部において漏電が発生していなければ、電圧Ｖｎは抵抗Ｒ１のみに依存する。すなわち、漏電が発生していないとき、電圧Ｖｎは、電圧Ｖの周波数ｆが変動しても一定である。このことは、判定回路６１３が波高値抽出回路６１０〜６１２から受ける波高値Ｈ１〜Ｈ３が、周波数の変動に伴って変化しないことに相当する。したがって、判定回路６１３は、波高値抽出回路６１０〜６１２から受けた波高値Ｈ１〜Ｈ３が変動していなければ交流部において漏電が発生していないと判定する。
【０１３７】
次に、直流部における漏電の有無の判定方法について説明する。直流電源Ｂ１からインバータ２０までの直流部において漏電が発生した場合、漏電インピーダンスＺは抵抗成分２７から成るインピーダンスに相当する。そして、直流部において漏電が発生した場合、発振回路４０から出力された交流信号Ｅ_０は、抵抗５０、カップリングコンデンサ１５、抵抗成分２７から成る漏電インピーダンスＺ、およびアースラインＧＮＤの経路を伝達される。したがって、直流部において漏電が発生した場合の等価回路は図６に示す回路の漏電インピーダンスＺを抵抗成分２７の抵抗値に代えたものに相当する。
【０１３８】
抵抗成分２７の抵抗値を抵抗Ｒ２とすると、図６に示す等価回路の全インピーダンスＺ０は、抵抗Ｒ１、容量Ｃ１および抵抗抵抗Ｒ２を直列に接続したものであるが、ノードＮ１における電圧Ｖｎは、漏電が発生するか否か、つまり、漏電インピーダンスＺ（すなわち、抵抗Ｒ２）の変動に大きく影響されるので、全インピーダンスＺの値は、抵抗Ｒ２に大きく依存する。
【０１３９】
このように、直流部において漏電が発生した場合、全インピーダンスＺ０に大きく影響を与えるのは、抵抗成分２７であるので、直流部において漏電が発生した場合、ノードＮ１における電圧Ｖｎは、電圧Ｖの周波数が変動しても一定である。
【０１４０】
このことは、判定回路６１３が波高値抽出回路６１０〜６１２から受ける波高値Ｈ１〜Ｈ３が周波数の変動に伴って変化しないことに相当する。したがって、判定回路６１３は、波高値抽出回路６１０〜６１２から受けた波高値Ｈ１〜Ｈ３が変動していなければ、その受けた波高値Ｈ１〜Ｈ３が基準値よりも小さいか否かを判定する。そして、判定回路６１３は、波高値Ｈ１〜Ｈ３が基準値よりも大きいとき直流部において漏電が発生していると判定し、波高値Ｈ１〜Ｈ３が基準値よりも小さいとき直流部において漏電が発生していないと判定する。
【０１４１】
判定回路６１３は、上述した方法によって、交流部において漏電が発生していると判定したとき、信号ＤＥＬを生成して制御装置３０へ出力する。
【０１４２】
なお、以下においては、交流部において漏電が発生した場合の負荷駆動装置１００における制御について説明する。
【０１４３】
図７は、図１に示す負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作を説明するためのフローチャートである。図７を参照して、一連の動作が開始されると、漏電検出器７０は、上述した方法によって交流部における漏電の発生を検出したとき信号ＤＥＬを生成して制御装置３０へ出力する。コンバータ制御手段３０２の判定部３６は、漏電検出器７０から信号ＤＥＬを受けたか否かを判定することにより、漏電が発生したか否かを判定する（ステップＳ１）。そして、ステップＳ１において、漏電が発生したと判定すると、判定部３６は、上述した方法によって昇圧コンバータ１１が昇圧動作中か否かを判定する（ステップＳ２）。そして、判定部３６は、昇圧コンバータ１１が昇圧動作中でないと判定したとき、信号ＬＫＥを生成して表示装置（図示せず）へ出力する。表示装置は、信号ＬＫＥに応じて、交流部において漏電が発生したことを示す警告灯を点灯する（ステップＳ３）。その後、一連の動作が終了する。
【０１４４】
一方、ステップＳ２において、判定部３６は、昇圧コンバータ１１が昇圧動作中であると判定したとき、信号ＣＴＬを生成して電圧指令演算部３３へ出力する。電圧指令演算部３３は、判定部３６からの信号ＣＴＬに応じて、電圧センサー１０からの直流電圧Ｖｂからなる電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ１（電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋの一種）を演算してコンバータ用デューティー比演算部３４へ出力する。
【０１４５】
コンバータ用デューティー比演算部３４は、電圧指令演算部３３からの電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ１（＝Ｖｂ）、電圧センサー１０からの直流電圧Ｖｂ、および電圧センサー１６からの電圧Ｖｍに基づいて、上述した方法によって、電圧Ｖｍを直流電圧Ｖｂに降圧するためのデューティー比ＤＲ１を演算し、その演算したデューティー比ＤＲ１をコンバータ用ＰＷＭ信号変換部３５へ出力する。
【０１４６】
そうすると、コンバータ用ＰＷＭ信号変換部３５は、コンバータ用デューティー比演算部３４からのデューティー比ＤＲ１に基づいて、上述した方法によって信号ＰＷＭＬ１（信号ＰＷＭＬの一種）を生成し、その生成した信号ＰＷＭＬ１を昇圧コンバータ１１のＮＰＮトランジスタＱ１，Ｑ２へ出力する。
【０１４７】
この信号ＰＷＭＬ１は、ＮＰＮトランジスタＱ１をオンし続け、ＮＰＮトランジスタＱ２をオフし続けるための信号である。したがって、コンバータ用ＰＷＭ信号変換部３５が信号ＰＷＭＬ１をＮＰＮトランジスタＱ１，Ｑ２へ出力することによって、ＮＰＮトランジスタＱ２のオフ制御およびＮＰＮトランジスタＱ１のオン制御が行なわれる（ステップＳ４，Ｓ５）。
【０１４８】
そうすると、ＮＰＮトランジスタＱ２は、信号ＰＷＭＬ１に応じてオフされ、ＮＰＮトランジスタＱ１は、信号ＰＷＭＬ１に応じてオンされる。そして、昇圧コンバータ１１は、コンデンサ１２側の直流電流を直流電源Ｂ１側へ供給して電圧Ｖｍを直流電圧Ｖｂ（「電源電圧」ともいう。）に降圧する。
【０１４９】
そして、コンバータ制御手段３０２の判定部３６は、電圧センサー１６からの電圧Ｖｍが電圧センサー１０からの直流電圧Ｖｂに一致するか否かを判定し（ステップＳ６）、電圧Ｖｍが直流電圧Ｖｂに一致しないとき信号ＣＴＬを生成して電圧指令演算部３３へ出力する。そして、ステップＳ４〜Ｓ６が繰返し実行される。
【０１５０】
一方、ステップＳ６において、電圧Ｖｍが直流電圧Ｖｂに一致すると判定されたとき、判定部３６は、信号ＳＴＰを生成してコンバータ用デューティー比演算部３４へ出力する。そして、コンバータ用デューティー比演算部３４は、判定部３６から信号ＳＴＰを受けるとＮＰＮトランジスタＱ１のオンデューティーを０％に設定したデューティー比を演算してコンバータ用ＰＷＭ信号変換部３５へ出力する。そして、コンバータ用ＰＷＭ信号変換部３５は、ＮＰＮトランジスタＱ１をオフするための信号を生成してＮＰＮトランジスタＱ１へ出力する。すなわち、コンバータ制御手段３０２は、ＮＰＮトランジスタＱ１をオフ制御する（ステップＳ７）。その後、一連の動作は終了する。
【０１５１】
図７に示すフローチャートは、交流部において漏電が発生した場合、インバータ２０側の直流電圧Ｖｍを電源電圧Ｖｂに降圧して直流電源Ｂ１に供給するフローチャートである。したがって、コンバータ制御手段３０２は、負荷駆動装置１００の交流部において漏電が発生した場合、インバータ２０側の直流電圧Ｖｍを電源電圧Ｖｂまで降圧して直流電源Ｂ１に供給するようにＮＰＮトランジスタＱ１をオン制御する。これにより、インバータ２０側の直流電圧Ｖｍは、電源電圧Ｖｂまで低下するので、漏電電流を最大限抑制できる。
【０１５２】
負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作は、図８に示すフローチャートに従って行なわれてもよい。図８は、図１に示す負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作を説明するための他のフローチャートである。
【０１５３】
図８に示すフローチャートは、図７に示すフローチャートのステップＳ５，Ｓ６をそれぞれステップＳ５Ａ，Ｓ６Ａに代えたものであり、その他は、図７に示すフローチャートと同じである。図８を参照して、ステップＳ２において昇圧コンバータ１１が昇圧動作中であると判定されると、電圧指令演算部３３は、所定の電圧Ｖｒｅｆ１からなる電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ２（電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋの一種）を演算してコンバータ用デューティー比演算部３４へ出力する。この所定の電圧Ｖｒｅｆ１は、電源電圧Ｖｂよりも高く、かつ、直流電圧Ｖｍよりも低い電圧である。
【０１５４】
コンバータ用デューティー比演算部３４は、電圧指令演算部３３からの電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ２（＝Ｖｒｅｆ１）、電圧センサー１０からの直流電圧Ｖｂ、および電圧センサー１６からの電圧Ｖｍに基づいて、上述した方法によって、電圧Ｖｍを所定の電圧Ｖｒｅｆ１に降圧するためのデューティー比ＤＲ２を演算し、その演算したデューティー比ＤＲ２をコンバータ用ＰＷＭ信号変換部３５へ出力する。
【０１５５】
そうすると、コンバータ用ＰＷＭ信号変換部３５は、コンバータ用デューティー比演算部３４からのデューティー比ＤＲ２に基づいて、上述した方法によって信号ＰＷＭＬ２（信号ＰＷＭＬの一種）を生成し、その生成した信号ＰＷＭＬ２を昇圧コンバータ１１のＮＰＮトランジスタＱ１，Ｑ２へ出力する。
【０１５６】
この信号ＰＷＭＬ２は、ＮＰＮトランジスタＱ１をスイッチングし、ＮＰＮトランジスタＱ２をオフし続けるための信号である。したがって、コンバータ用ＰＷＭ信号変換部３５が信号ＰＷＭＬ２をＮＰＮトランジスタＱ１，Ｑ２へ出力することによって、ＮＰＮトランジスタＱ２のオフ制御およびＮＰＮトランジスタＱ１のスイッチング制御が行なわれる（ステップＳ４，Ｓ５Ａ）。
【０１５７】
そうすると、ＮＰＮトランジスタＱ２は、信号ＰＷＭＬ２に応じてオフされ、ＮＰＮトランジスタＱ１は、信号ＰＷＭＬ２に応じてスイッチングされる。そして、昇圧コンバータ１１は、ＮＰＮトランジスタＱ１のオン期間中、コンデンサ１２側の直流電流を直流電源Ｂ１側へ供給して電圧Ｖｍを所定の電圧Ｖｒｅｆ１に降圧する。
【０１５８】
そして、コンバータ制御手段３０２の判定部３６は、電圧センサー１６からの電圧Ｖｍが所定の電圧Ｖｒｅｆ１以下か否かを判定し（ステップＳ６Ａ）、電圧Ｖｍが所定の電圧Ｖｒｅｆ１以下でないとき信号ＣＴＬを生成して電圧指令演算部３３へ出力する。そして、ステップＳ４，Ｓ５Ａ，Ｓ６Ａが繰返し実行される。
【０１５９】
一方、ステップＳ６Ａにおいて、電圧Ｖｍが所定の電圧Ｖｒｅｆ１以下であると判定されたとき、判定部３６は、信号ＳＴＰを生成してコンバータ用デューティー比演算部３４へ出力する。その後、上述した動作が行なわれる。
【０１６０】
なお、所定の電圧Ｖｒｅｆ１は、直流電圧Ｖｍと電源電圧Ｖｂとの電圧差が所定値になるときの電圧である。たとえば、所定の電圧Ｖｒｅｆ１は、電源電圧Ｖｂが２１０Ｖであるとき、２５０Ｖに設定される。このとき、所定値は４０Ｖである。したがって、昇圧コンバータ１１は、直流電圧Ｖｍを２５０Ｖまで降圧させると、停止される。
【０１６１】
図８に示すフローチャートは、交流部において漏電が発生した場合、インバータ２０側の直流電圧ＶｍをＮＰＮトランジスタＱ１のスイッチング動作により所定の電圧Ｖｒｅｆ１まで降圧して直流電源Ｂ１に供給するフローチャートである。したがって、コンバータ制御手段３０２は、昇圧コンバータ１１の昇圧動作中に交流部において漏電が発生した場合、インバータ２０側の直流電圧Ｖｍを所定の電圧Ｖｒｅｆ１に降圧して直流電源Ｂ１に供給するようにＮＰＮトランジスタＱ１をスイッチング制御する。
【０１６２】
これにより、インバータ２０側の直流電圧Ｖｍは所定の電圧Ｖｒｅｆ１まで低下し、交流部における漏電電流を抑制できる。
【０１６３】
また、図８に示すフローチャートにおいては、インバータ２０側の直流電圧Ｖｍが電源電圧Ｖｂよりも高い所定の電圧Ｖｒｅｆ１まで降圧されると、昇圧コンバータ１１の降圧動作を停止するので（ステップＳ６Ａ，Ｓ７参照）、漏電電流の抑制動作を行なう期間を短縮できる。
【０１６４】
負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作は、図９に示すフローチャートに従って行なわれてもよい。負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作が図９に示すフローチャートに従って行なわれる場合、制御装置３０は、コンバータ制御手段３０２に代えて図１０に示すコンバータ制御手段３０２Ａを含む。
【０１６５】
図１０は、コンバータ制御手段の他の機能ブロック図である。図１０を参照して、コンバータ制御手段３０２Ａは、コンバータ制御手段３０２の電圧指令演算部３３を電圧指令演算部３３Ａに代え、コンバータ用デューティー比演算部３４をコンバータ用デューティー比演算部３４Ａに代え、判定部３６を判定部３６Ａに代えたものであり、その他は、コンバータ制御手段３０２と同じである。
【０１６６】
電圧指令演算部３３Ａは、判定部３６Ａから信号ＣＴＬ１を受けると、直流電圧Ｖｍを所定の電圧Ｖｒｅｆ２まで降圧するための電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３１（電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋの一種）を演算してコンバータ用デューティー比演算部３４Ａへ出力する。
【０１６７】
なお、所定の電圧Ｖｒｅｆ２は、ＮＰＮトランジスタＱ１のオンデューティーを１００％に設定しても、すなわち、ＮＰＮトランジスタＱ１をオンし続けても過電流よりも小さい直流電流がＮＰＮトランジスタＱ１に流れるときの電圧である。
【０１６８】
また、電圧指令演算部３３Ａは、判定部３６Ａから信号ＣＴＬ２を受けると、直流電圧Ｖｍを電源電圧Ｖｂまで降圧するための電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３２（電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋの一種）を演算してコンバータ用デューティー比演算部３４Ａへ出力する。
【０１６９】
電圧指令演算部３３Ａは、その他、電圧指令演算部３３と同じ機能を果たす。
コンバータ用デューティー比演算部３４Ａは、電圧指令演算部３３Ａからの電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３１に応じて、過電流よりも小さい直流電流をＮＰＮトランジスタＱ１に流すためのデューティー比ＤＲ３（「保護デューティー比」と言う。）を演算してコンバータ用ＰＷＭ信号変換部３５へ出力する。
【０１７０】
また、コンバータ用デューティー比演算部３４Ａは、電圧指令演算部３３Ａからの電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３２に応じて、直流電圧Ｖｍを電源電圧Ｖｂまで降圧するためのデューティー比ＤＲ１を演算してコンバータ用ＰＷＭ信号変換部３５へ出力する。
【０１７１】
コンバータ用デューティー比演算部３４Ａは、その他、コンバータ用デューティー比演算部３４と同じ機能を果たす。
【０１７２】
判定部３６Ａは、判定部３６と同じ方法により昇圧コンバータ１１が昇圧動作中か降圧動作中かを判定し、昇圧動作中であると判定したとき信号ＣＴＬ１を生成して電圧指令演算部３３Ａへ出力する。
【０１７３】
また、判定部３６Ａは、信号ＣＴＬ１を電圧指令演算部３３Ａへ出力した後、電圧センサー１６からの電圧Ｖｍが所定の電圧Ｖｒｅｆ２以下か否かを判定する。そして、判定部３６Ａは、電圧Ｖｍが所定の電圧Ｖｒｅｆ２よりも高いとき信号ＣＴＬ１を生成して電圧指令演算部３３Ａへ出力し、電圧Ｖｍが所定の電圧Ｖｒｅｆ２以下であるとき信号ＣＴＬ２を生成して電圧指令演算部３３Ａへ出力する。
【０１７４】
判定部３６Ａは、その他、判定部３６と同じ機能を果たす。
図９は、図１に示す負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作を説明するためのさらに他のフローチャートである。そして、図９に示すフローチャートは、図７に示すフローチャートのステップＳ４〜Ｓ６をステップＳ１０〜Ｓ１５に代えたものであり、その他は、図７に示すフローチャートと同じである。
【０１７５】
図９を参照して、ステップＳ２において昇圧コンバータ１１が昇圧動作中であると判定されると、判定部３６Ａは、信号ＣＴＬ１を生成して電圧指令演算部３３Ａへ出力する。電圧指令演算部３３Ａは、判定部３６Ａからの信号ＣＴＬ１に応じて、所定の電圧Ｖｒｅｆ２からなる電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３１を演算してコンバータ用デューティー比演算部３４Ａへ出力する。
【０１７６】
コンバータ用デューティー比演算部３４Ａは、電圧指令演算部３３Ａからの電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３１（＝Ｖｒｅｆ２）、電圧センサー１０からの直流電圧Ｖｂ、および電圧センサー１６からの電圧Ｖｍに基づいて、上述した方法によって、電圧Ｖｍを所定の電圧Ｖｒｅｆ２に降圧するためのデューティー比ＤＲ３（保護デューティー比）を演算し、その演算したデューティー比ＤＲ３をコンバータ用ＰＷＭ信号変換部３５へ出力する。すなわち、コンバータ制御手段３０２Ａは、保護デューティー比を決定する（ステップＳ１０）。
【０１７７】
そうすると、コンバータ用ＰＷＭ信号変換部３５は、コンバータ用デューティー比演算部３４Ａからのデューティー比ＤＲ３に基づいて、上述した方法によって信号ＰＷＭＬ３（信号ＰＷＭＬの一種）を生成し、その生成した信号ＰＷＭＬ３を昇圧コンバータ１１のＮＰＮトランジスタＱ１，Ｑ２へ出力する。
【０１７８】
この信号ＰＷＭＬ３は、ＮＰＮトランジスタＱ１をデューティー比ＤＲ３（保護デューティー比）でスイッチングし、ＮＰＮトランジスタＱ２をオフし続けるための信号である。したがって、コンバータ用ＰＷＭ信号変換部３５が信号ＰＷＭＬ３をＮＰＮトランジスタＱ１，Ｑ２へ出力することによって、ＮＰＮトランジスタＱ２のオフ制御およびＮＰＮトランジスタＱ１の保護デューティー比によるスイッチング制御が行なわれる（ステップＳ１１，Ｓ１２）。
【０１７９】
そうすると、ＮＰＮトランジスタＱ２は、信号ＰＷＭＬ３に応じてオフされ、ＮＰＮトランジスタＱ１は、信号ＰＷＭＬ３に応じて保護デューティー比でスイッチングされる。そして、昇圧コンバータ１１は、ＮＰＮトランジスタＱ１のオン期間中、過電流よりも小さい直流電流をＮＰＮトランジスタＱ１に流しながらコンデンサ１２側の直流電流を直流電源Ｂ１側へ供給して電圧Ｖｍを所定の電圧Ｖｒｅｆ２に降圧する。
【０１８０】
そして、コンバータ制御手段３０２Ａの判定部３６Ａは、電圧センサー１６からの電圧Ｖｍが所定の電圧Ｖｒｅｆ２以下か否かを判定し（ステップＳ１３）、電圧Ｖｍが所定の電圧Ｖｒｅｆ２以下でないとき信号ＣＴＬ１を生成して電圧指令演算部３３Ａへ出力する。そして、ステップＳ１０〜Ｓ１３が繰返し実行される。
【０１８１】
一方、ステップＳ１３において、電圧Ｖｍが所定の電圧Ｖｒｅｆ２以下であると判定されたとき、判定部３６Ａは、信号ＣＴＬ２を生成して電圧指令演算部３３Ａへ出力する。電圧指令演算部３３Ａは、信号ＣＴＬ２に応じて、電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３２を演算してコンバータ用デューティー比演算部３４Ａへ出力する。
【０１８２】
そうすると、コンバータ用デューティー比演算部３４Ａは、電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３２に応じて、上述したディーティー比ＤＲ１を生成してコンバータ用ＰＷＭ信号変換部３５へ出力する。そして、コンバータ用ＰＷＭ信号変換部３５は、デューティー比ＤＲ１に基づいて、信号ＰＷＭＬ１を生成して昇圧コンバータ１１のＮＰＮトランジスタＱ１，Ｑ２へ出力する。
【０１８３】
信号ＰＷＭＬ１は、上述したように、ＮＰＮトランジスタＱ１をオンし続け、ＮＰＮトランジスタＱ２をオフし続けるための信号である。したがって、コンバータ用ＰＷＭ信号変換部３５が信号ＰＷＭＬ１をＮＰＮトランジスタＱ１，Ｑ２へ出力することによって、ＮＰＮトランジスタＱ２は、ステップＳ１１においてオフされてから継続してオフされ、ＮＰＮトランジスタＱ１のオン制御が行なわれる（ステップＳ１４）。
【０１８４】
そうすると、ＮＰＮトランジスタＱ２は、信号ＰＷＭＬ１に応じて継続してオフされ、ＮＰＮトランジスタＱ１は、信号ＰＷＭＬ１に応じて、常時、オンされる。そして、昇圧コンバータ１１は、コンデンサ１２側の直流電流を直流電源Ｂ１側へ供給して電圧Ｖｍを電源電圧Ｖｂに降圧する。
【０１８５】
そして、コンバータ制御手段３０２Ａの判定部３６Ａは、電圧センサー１６からの電圧Ｖｍが電圧センサー１０からの直流電圧Ｖｂに一致するか否かを判定し（ステップＳ１５）、電圧Ｖｍが直流電圧Ｖｂに一致しないとき信号ＣＴＬ２を生成して電圧指令演算部３３Ａへ出力する。そして、ステップＳ１４，Ｓ１５が繰返し実行される。
【０１８６】
一方、ステップＳ１５において、電圧Ｖｍが直流電圧Ｖｂに一致すると判定されたとき、判定部３６Ａは、信号ＳＴＰを生成してコンバータ用デューティー比演算部３４Ａへ出力する。その後、上述した動作が行なわれる。
【０１８７】
図９に示すフローチャートは、交流部において漏電が発生した場合、過電流よりも小さい直流電流をＮＰＮトランジスタＱ１に流しながらインバータ２０側の直流電圧ＶｍをＮＰＮトランジスタＱ１のスイッチング動作により所定の電圧Ｖｒｅｆ２まで降圧し、直流電圧Ｖｍが所定の電圧Ｖｒｅｆ２まで降圧されるとＮＰＮトランジスタＱ１をオンし続けて直流電圧Ｖｍを電源電圧Ｖｂまで降圧するフローチャートである。そして、所定の電圧Ｖｒｅｆ２は、ＮＰＮトランジスタＱ１をオンし続けても過電流よりも小さい直流電流がＮＰＮトランジスタＱ１に流れる電圧である。
【０１８８】
したがって、コンバータ制御手段３０２Ａは、昇圧コンバータ１１の昇圧動作中に交流部において漏電が発生した場合、過電流よりも小さい直流電流をＮＰＮトランジスタＱ１に流しながら、インバータ２０側の直流電圧Ｖｍを所定の電圧Ｖｒｅｆ２および電源電圧Ｖｂへ順次降圧するようにＮＰＮトランジスタＱ１を制御する。
【０１８９】
これにより、インバータ２０側の直流電圧Ｖｍは電源電圧Ｖｂまで低下し、ＮＰＮトランジスタＱ１を保護しながら交流部における漏電電流を最大限抑制できる。
【０１９０】
このように、コンバータ制御手段３０２Ａは、過電流よりも小さい直流電流がＮＰＮトランジスタＱ１に流れるようにＮＰＮトランジスタＱ１を制御してＮＰＮトランジスタＱ１を保護しながら、インバータ２０側の直流電圧Ｖｍを電源電圧Ｖｂまで低下させることにより漏電電流を最大限抑制するように昇圧コンバータ１１を制御する。
【０１９１】
コンバータ制御手段３０２Ａのコンバータ用デューティー比演算部３４Ａは、電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３１に応じて、過電流よりも小さい直流電流をＮＰＮトランジスタＱ１に流すためのデューティー比ＤＲ３（保護デューティー比）を演算するが、この保護デューティー比は、漏電が発生したときの直流電圧Ｖｍの電圧レベルによって変化する。すなわち、漏電が発生したときの直流電圧Ｖｍの電圧レベルが相対的に高いとき、保護デューティー比のオンデューティーは、相対的に小さくなり、漏電が発生したときの直流電圧Ｖｍの電圧レベルが相対的に低いとき、保護デューティー比のオンデューティーは、相対的に大きくなる。
【０１９２】
より具体的には、ＮＰＮトランジスタＱ１の過電流をＩｌｉｍとし、ＮＰＮトランジスタＱ１のオン抵抗をＲ_ＯＮとし、保護デューティー比のオンデューティーをＤＲ_ＯＮとしたとき、次式が成立する。
【０１９３】
【数３】

【０１９４】
式（３）より、保護デューティー比のオンデューティーＤＲ_ＯＮは、インバータ２０側の直流電圧Ｖｍに反比例する。
【０１９５】
図１１は、保護デューティー比のオンデューティーＤＲ_ＯＮとインバータ２０側における直流電圧Ｖｍとの関係を示す図である。曲線ｋ１は、直流電圧Ｖｍがコンデンサ１２側から昇圧コンバータ１１に印加されたときに、過電流よりも小さい直流電流をＮＰＮトランジスタＱ１に流すためのオンデューティーＤＲ_ＯＮと直流電圧Ｖｍとの関係を示す。そして、オンデューティーＤＲ_ＯＮは、直流電圧Ｖｍに反比例する。
【０１９６】
コンバータ用デューティー比演算部３４Ａは、図１１に示すマップを保持しており、電圧指令演算部３３Ａから電圧指令Ｖｄｃ＿ｃｏｍ＿ｌｋ３１を受けると、電圧センサー１６からの直流電圧Ｖｍに対応するオンデューティーＤＲ_ＯＮを図１１に示すマップから抽出する。そして、コンバータ用デューティー比演算部３４Ａは、抽出したオンデューティーＤＲ_ＯＮを用いて保護デューティー比ＤＲ３を演算し、その演算した保護デューティー比ＤＲ３をコンバータ用ＰＷＭ信号変換部３５へ出力する。
【０１９７】
したがって、図９に示すステップＳ１０においては、図１１に示すマップを参照して、電圧センサー１６により検出された直流電圧Ｖｍに対応するオンデューティーＤＲ_ＯＮを抽出して保護デューティー比を決定するようにしてもよい。また、オンデューティーＤＲ_ＯＮは、保護デューティー比ＤＲ３と等価であるので、コンバータ用デューティー比演算部３４Ａは、保護デューティー比ＤＲ３と直流電圧Ｖｍとの関係を示すマップを保持しており、電圧センサー１６により検出された直流電圧Ｖｍに対応する保護デューティー比をマップを参照して抽出するようにしてもよい。この場合、保護デューティー比ＤＲ３と直流電圧Ｖｍとの関係を示すマップは、図１１に示す曲線ｋ１と同じ曲線になる。
【０１９８】
このように、図１１に示すマップに従って保護デューティー比ＤＲ３を決定する場合、ＮＰＮトランジスタＱ１のオンデューティーは、直流電圧Ｖｍが相対的に高いときは相対的に短くなり、直流電圧Ｖｍが相対的に低いときは相対的に長くなる。
【０１９９】
したがって、ＮＰＮトランジスタＱ１に流れる直流電流がＮＰＮトランジスタＱ１の過電流よりも小さくなるようにＮＰＮトランジスタＱ１のオンデューティーが直流電圧Ｖｍの電圧レベルに応じて決定されるので、直流電圧Ｖｍの電圧レベルが変動してもＮＰＮトランジスタＱ１を保護しながら漏電電流を抑制できる。
【０２００】
負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作は、図１２に示すフローチャートに従って行なわれてもよい。負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作が図１２に示すフローチャートに従って行なわれる場合、制御装置３０は、コンバータ制御手段３０２に代えて図１３に示すコンバータ制御手段３０２Ｂを含む。
【０２０１】
図１３は、コンバータ制御手段のさらに他の機能ブロック図である。図１３を参照して、コンバータ制御手段３０２Ｂは、コンバータ制御手段３０２の判定部３６を判定部３６Ｂに代え、演算部３７を追加したものであり、その他は、コンバータ制御手段３０２と同じである。
【０２０２】
演算部３７は、電流センサー１７からの直流電流ＢＣＲＴに基づいて、直流電源Ｂ１の容量ＳＯＣ（Ｓｃａｌｅ Ｏｆ Ｃｈａｒｇｅ）を積算し、その積算した容量ＳＯＣを判定部３６Ｂへ出力する。
【０２０３】
判定部３６Ｂは、演算部３７からの容量ＳＯＣが直流電源Ｂ１の満充電量に達しているか否かを判定する。そして、判定部３６Ｂは、容量ＳＯＣが直流電源Ｂ１の満充電量に達しているとき、信号ＣＴＬおよびＬレベルの信号ＳＥを生成し、その生成した信号ＣＴＬを電圧指令演算部３３へ出力し、Ｌレベルの信号ＳＥをシステムリレーＳＲ１，ＳＲ２へ出力する。また、判定部３６Ｂは、容量ＳＯＣが直流電源Ｂ１の満充電量に達していないとき、信号ＣＴＬを生成して電圧指令演算部３３へ出力する。
【０２０４】
判定部３６Ｂは、その他、判定部３６と同じ機能を果たす。
図１２は、図１に示す負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作を説明するためのさらに他のフローチャートである。そして、図１２に示すフローチャートは、図７に示すフローチャートのステップＳ２とステップＳ４との間にステップＳ２１，Ｓ２２を挿入したものであり、その他は、図７に示すフローチャートと同じである。
【０２０５】
図１２を参照して、ステップＳ２において、昇圧コンバータ１１が昇圧動作中であると判定されると、判定部３６Ｂは、演算部３７からの容量ＳＯＣが直流電源Ｂ１の満充電量に達しているか否かを判定し（ステップＳ２１）、容量ＳＯＣが直流電源Ｂ１の満充電量に達していないとき、信号ＣＴＬを生成して電圧指令演算部３３へ出力する。そして、上述したステップＳ４〜Ｓ７が実行される。
【０２０６】
一方、ステップＳ２１において、容量ＳＯＣが直流電源Ｂ１の満充電量に達していると判定されたとき、判定部３６Ｂは、Ｌレベルの信号ＳＥを生成してシステムリレーＳＲ１，ＳＲ２へ出力する。そして、システムリレーＳＲ１，ＳＲ２は、Ｌレベルの信号ＳＥによりオフされる（ステップＳ２２）。その後、上述したステップＳ４〜Ｓ７が実行され、昇圧コンバータ１１は、直流電圧Ｖｍを電源電圧Ｖｂまで降圧し、ＤＣ／ＤＣコンバータ１３およびエアコン１４へ供給する。そして、ＤＣ／ＤＣコンバータ１３は、昇圧コンバータ１１からの直流電圧の電圧レベルを変換して直流電源Ｂ２を充電する。また、エアコン１４は、昇圧コンバータ１１からの直流電圧により駆動される。その他、上述したとおりである。
【０２０７】
図１２に示すフローチャートは、昇圧コンバータ１１の昇圧動作中に負荷駆動装置１００の交流部において漏電が発生したとき、直流電源Ｂ１の容量ＳＯＣが満充電量に達しているか否かを判定し、直流電源Ｂ１の容量ＳＯＣが満充電量に達しているときは、直流電圧Ｖｍを電源電圧Ｖｂまで降圧してＤＣ／ＤＣコンバータ１３およびエアコン１４へ供給し、直流電源Ｂ１の容量ＳＯＣが満充電量に達していないときは、直流電圧Ｖｍを電源電圧Ｖｂまで降圧して直流電源Ｂ１へ供給するものである。
【０２０８】
これにより、直流電源Ｂ１を保護しながら漏電電流を最大限抑制できる。
負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作は、図１４に示すフローチャートに従って行なわれてもよい。負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作が図１４に示すフローチャートに従って行なわれる場合、制御装置３０は、コンバータ制御手段３０２に代えて図１３に示すコンバータ制御手段３０２Ｂを含む。
【０２０９】
図１４は、図１に示す負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作を説明するためのさらに他のフローチャートである。そして、図１４に示すフローチャートは、図８に示すフローチャートのステップＳ２とステップＳ４との間にステップＳ２１，Ｓ２２を挿入したものであり、その他は、図８に示すフローチャートと同じである。
【０２１０】
ステップＳ２１，Ｓ２２については、図１２において説明したとおりである。
図１４に示すフローチャートは、昇圧コンバータ１１の昇圧動作中に負荷駆動装置１００の交流部において漏電が発生したとき、直流電源Ｂ１の容量ＳＯＣが満充電量に達しているか否かを判定し、直流電源Ｂ１の容量ＳＯＣが満充電量に達しているときは、直流電圧Ｖｍを所定の電圧Ｖｒｅｆ１まで降圧してＤＣ／ＤＣコンバータ１３およびエアコン１４へ供給し、直流電源Ｂ１の容量ＳＯＣが満充電量に達していないときは、直流電圧Ｖｍを所定の電圧Ｖｒｅｆ１まで降圧して直流電源Ｂ１へ供給するものである。
【０２１１】
これにより、直流電源Ｂ１を保護しながら漏電電流を抑制できる。また、漏電電流を抑制する動作期間を短縮できる。
【０２１２】
負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作は、図１５に示すフローチャートに従って行なわれてもよい。負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作が図１５に示すフローチャートに従って行なわれる場合、制御装置３０は、コンバータ制御手段３０２に代えて図１６に示すコンバータ制御手段３０２Ｃを含む。
【０２１３】
図１６は、コンバータ制御手段のさらに他の機能ブロック図である。図１６を参照して、コンバータ制御手段３０２Ｃは、コンバータ制御手段３０２Ａの判定部３６Ａを判定部３６Ｃに代え、演算部３７を追加したものであり、その他は、コンバータ制御手段３０２Ａと同じである。
【０２１４】
演算部３７については、上述したとおりである。判定部３６Ｃは、演算部３７からの容量ＳＯＣが直流電源Ｂ１の満充電量に達したか否かを判定し、容量ＳＯＣが直流電源Ｂ１の満充電量に達していないとき、信号ＣＴＬ１を生成して電圧指令演算部３３Ａへ出力する。また、判定部３６Ｃは、容量ＳＯＣが直流電源Ｂ１の満充電量に達しているとき、信号ＣＴＬ１およびＬレベルの信号ＳＥを生成し、その生成した信号ＣＴＬ１を電圧指令演算部３３Ａへ出力し、生成したＬレベルの信号ＳＥをシステムリレーＳＲ１，ＳＲ２へ出力する。
【０２１５】
判定部３６Ｃは、その他、判定部３６および３６Ａと同じ機能を果たす。
図１５は、図１に示す負荷駆動装置１００における漏電発生時に漏電電流を抑制する動作を説明するためのさらに他のフローチャートである。そして、図１５に示すフローチャートは、図９に示すフローチャートのステップＳ２とステップＳ１０との間にステップＳ２１，Ｓ２２を挿入したものであり、その他は、図９に示すフローチャートと同じである。
【０２１６】
ステップＳ２１，Ｓ２２については、図１２において説明したとおりである。
図１５に示すフローチャートは、昇圧コンバータ１１の昇圧動作中に負荷駆動装置１００の交流部において漏電が発生したとき、直流電源Ｂ１の容量ＳＯＣが満充電量に達しているか否かを判定し、直流電源Ｂ１の容量ＳＯＣが満充電量に達しているときは、ＮＰＮトランジスタＱ１を保護しながら直流電圧Ｖｍを所定の電圧Ｖｒｅｆ２および電源電圧Ｖｂまで順次降圧してＤＣ／ＤＣコンバータ１３およびエアコン１４へ供給し、直流電源Ｂ１の容量ＳＯＣが満充電量に達していないときは、ＮＰＮトランジスタＱ１を保護しながら直流電圧Ｖｍを所定の電圧Ｖｒｅｆ２および電源電圧Ｖｂまで順次降圧して直流電源Ｂ１へ供給するものである。
【０２１７】
これにより、直流電源Ｂ１およびＮＰＮトランジスタＱ１を保護しながら漏電電流を最大限抑制できる。
【０２１８】
上述したように、この発明においては、昇圧コンバータ１１の昇圧動作中に負荷駆動装置１００の交流部において漏電が発生したとき、降圧動作を行なうように昇圧コンバータ１１を制御することを特徴とする（図７，１２のステップＳ４〜Ｓ６、図８，１４のステップＳ４，Ｓ５Ａ，Ｓ６Ａ、および図９，１５のステップＳ１０〜Ｓ１５参照）。
【０２１９】
この特徴により、インバータ２０側の直流電圧Ｖｍは降圧され、漏電電流を抑制することができる。
【０２２０】
なお、コンバータ制御手段３０２における漏電電流を抑制する動作は、実際には、ＣＰＵ（Ｃｅｎｔｒａｌ Ｐｒｏｃｅｓｓｉｎｇ Ｕｎｉｔ）によって実行され、ＣＰＵは、図７〜図９、図１２、図１４および図１５のいずれかに示すフローチャートの各ステップを備えるプログラムをＲＯＭ（Ｒｅａｄ Ｏｎｌｙ Ｍｅｍｏｒｙ）から読出し、その読出したプログラムを実行して図７〜図９、図１２、図１４および図１５のいずれかに示すフローチャートに従って負荷駆動装置１００における漏電電流を抑制する制御を行なう。
【０２２１】
したがって、ＲＯＭは、負荷駆動装置１００における漏電電流を抑制する制御を行なうプログラムを記録したコンピュータ（ＣＰＵ）読取り可能な記録媒体に相当する。
【０２２２】
また、交流モータＭ１は、「負荷」を構成する。
さらに、直流電源Ｂ２、ＤＣ／ＤＣコンバータ１３およびエアコン１４は、「補機」を構成する。
【０２２３】
再び、図１を参照して、負荷駆動装置１００における全体動作について説明する。一連の動作が開始されると、制御装置３０は、外部ＥＣＵからトルク指令値ＴＲおよびモータ回転数ＭＲＮを受ける。そして、制御装置３０は、Ｈレベルの信号ＳＥを生成してシステムリレーＳＲ１，ＳＲ２へ出力する。また、制御装置３０は、電圧センサー１０からの直流電圧Ｖｂ、電圧センサー１６からの電圧Ｖｍ、電流センサー２４からのモータ電流ＭＣＲＴ、トルク指令値ＴＲおよびモータ回転数ＭＲＮに基づいて、上述した方法によって交流モータＭ１がトルク指令値ＴＲによって指定されたトルクを発生するように昇圧コンバータ１１およびインバータ２０を制御するための信号ＰＷＭＵおよび信号ＰＷＭＩを生成してそれぞれ昇圧コンバータ１１およびインバータ２０へ出力する。
【０２２４】
そして、直流電源Ｂ１は直流電圧を出力し、システムリレーＳＲ１，ＳＲ２は直流電圧を昇圧コンバータ１１へ供給する。
【０２２５】
そうすると、昇圧コンバータ１１のＮＰＮトランジスタＱ１，Ｑ２は、制御装置３０からの信号ＰＷＭＵに応じてオン／オフされ、直流電圧を出力電圧Ｖｍに変換してコンデンサ１２に供給する。
【０２２６】
コンデンサ１２は、昇圧コンバータ１１から供給された直流電圧を平滑化してインバータ２０へ供給する。インバータ２０のＮＰＮトランジスタＱ３〜Ｑ８は、制御装置３０からの信号ＰＷＭＩに従ってオン／オフされ、インバータ２０は、直流電圧を交流電圧に変換し、トルク指令値ＴＲによって指定されたトルクを交流モータＭ１が発生するように交流モータＭ１のＵ相、Ｖ相、Ｗ相の各相に所定の交流電流を流す。これにより、交流モータＭ１は、トルク指令値ＴＲによって指定されたトルクを発生する。
【０２２７】
負荷駆動装置１００が搭載されたハイブリッド自動車または電気自動車が回生制動モードになった場合、制御装置３０は、直流電圧Ｖｂ、電圧Ｖｍ、モータ電流ＭＣＲＴ、トルク指令値ＴＲおよびモータ回転数ＭＲＮに基づいて、信号ＰＷＭＣおよび信号ＰＷＭＤを生成してそれぞれインバータ２０および昇圧コンバータ１１へ出力する。
【０２２８】
交流モータＭ１は、交流電圧を発電し、その発電した交流電圧をインバータ２０へ供給する。そして、インバータ２０は、制御装置３０からの信号ＰＷＭＣに従って、交流電圧を直流電圧に変換し、その変換した直流電圧をコンデンサ１２を介して昇圧コンバータ１１へ供給する。
【０２２９】
昇圧コンバータ１１は、制御装置３０からの信号ＰＷＭＤに従って直流電圧を降圧して直流電源Ｂ１に供給し、直流電源Ｂ１を充電する。
【０２３０】
そして、負荷駆動装置１００が交流モータＭ１を駆動しているとき、漏電検出器７０は、上述した方法によって、交流部における漏電を検出すると、交流部において漏電が発生したことを示す信号ＤＥＬを生成して制御装置３０へ出力する。
【０２３１】
そうすると、制御装置３０は、漏電が検出されたのが昇圧コンバータ１１の昇圧動作中であるか否かを判定し、昇圧コンバータ１１の昇圧動作中に漏電が検出されたと判定したとき、上述したように、降圧動作を行なうように昇圧コンバータ１１を制御する。
【０２３２】
また、制御装置３０は、昇圧コンバータ１１の降圧動作中に漏電が検出されたと判定したとき、信号ＬＫＥを生成して表示装置（図示せず）に出力する。そして、表示装置は、信号ＬＫＥに応じて警告灯を点灯する。
【０２３３】
これにより、昇圧コンバータ１１の昇圧動作中に漏電が検出されたとき、インバータ２０側の直流電圧Ｖｍは降圧されるので、漏電電流を抑制できる。
【０２３４】
［実施の形態２］
図１７は、実施の形態２による負荷駆動装置の概略ブロック図である。図１７を参照して、負荷駆動装置１００Ａは、負荷駆動装置１００の制御装置３０を制御装置３０Ａに代え、漏電検出器７０を漏電検出器８０に代えたものであり、その他は、負荷駆動装置１００と同じである。
【０２３５】
漏電検出器８０は、スイッチ８１と、コンデンサ８２と、電流センサー８３とを含む。スイッチ８１およびコンデンサ８２は、交流モータＭ１のＷ相コイルの一方端とアースラインＧＮＤとの間に直列に接続される。この場合、スイッチ８１は、交流モータＭ１側に接続され、コンデンサ８２は、アースラインＧＮＤ側に接続される。そして、電流センサー８３は、コンデンサ８２とアースラインＧＮＤとの間の配線に設置される。
【０２３６】
スイッチ８１は、制御装置３０Ａからの信号ＳＷにより周期的にオン／オフされる。コンデンサ８２は、実施の形態１における漏電検出器７０が検出可能な漏電電流よりも小さい漏電電流を検出可能な容量を有する。電流センサー８３は、スイッチ８１が信号ＳＷによりオンされたとき、電流ＩＬＥを検出し、その検出した電流ＩＬＥを制御装置３０Ａへ出力する。
【０２３７】
制御装置３０Ａは、スイッチ８１を周期的にオン／オフするための信号ＳＷを生成してスイッチ８１へ出力する。また、制御装置３０Ａは、電流センサー８３からの電流ＩＬＥを受け、その受けた電流ＩＬＥに基づいて、昇圧コンバータ１１の昇圧動作中に負荷駆動装置１００Ａの交流部において漏電が発生しているか否かを判定し、交流部において漏電が発生しているとき、上述したように、漏電電流を抑制するように昇圧コンバータ１１を制御する。
【０２３８】
制御装置３０Ａは、その他、制御装置３０と同じ機能を果たす。
制御装置３０Ａは、コンバータ制御手段３０２に代えて図１８に示すコンバータ制御手段３０２Ｄを含む。図１８は、コンバータ制御手段のさらに他の機能ブロック図である。
【０２３９】
図１８を参照して、コンバータ制御手段３０２Ｄは、コンバータ制御手段３０２の判定部３６を判定部３６Ｄに代えたものであり、その他は、コンバータ制御手段３０２と同じである。
【０２４０】
判定部３６Ｄは、電流センサー８３から電流ＩＬＥを受け、その受けた電流ＩＬＥがしきい値よりも大きいか否かを判定する。そして、判定部３６Ｄは、電流ＩＬＥがしきい値よりも大きいとき、交流部において漏電が発生したと判定し、信号ＣＴＬを生成して電圧指令演算部３３へ出力する。また、判定部３６Ｄは、電流ＩＬＥがしきい値以下であるとき、交流部において漏電が発生していないと判定する。
【０２４１】
判定部３６Ｄは、その他は、判定部３６と同じ機能を果たす。
漏電検出器８０は、スイッチ８１が制御装置３０Ａからの信号ＳＷによりオンされると、電流センサー８３により電流ＩＬＥを検出する。そして、コンバータ制御手段３０２Ｄの判定部３６Ｄは、電流センサー８３からの電流ＩＬＥがしきい値よりも大きいとき負荷駆動装置１００Ａの交流部において漏電が発生したと判定する。
【０２４２】
そして、コンデンサ８２を介して流れる電流ＩＬＥは、漏電検出器７０が検出可能な漏電電流よりも小さいので、漏電検出器８０は、漏電検出器７０が検出可能な漏電電流よりも小さい漏電電流を検出する漏電検出器である。
【０２４３】
漏電検出器８０のスイッチ８１を周期的にオン／オフさせているのは、コンデンサ８２の容量が小さいので、スイッチ８１を、常時、オンしておくと、大きな漏電電流がコンデンサ８２を介して流れ、コンデンサ８２が破損する虞がある。
【０２４４】
そこで、スイッチ８１を周期的にオン／オフさせ、コンデンサ８２の破損を防止することにしたものである。
【０２４５】
負荷駆動装置１００Ａにおける漏電発生時に漏電電流を抑制する動作は、図７〜図９、図１２、図１４および図１５のいずれかに示すフローチャートに従って行なわれる。
【０２４６】
負荷駆動装置１００Ａにおける漏電発生時に漏電電流を抑制する動作が図８、図９、図１２、図１４および図１５のいずれかに示すフローチャートに従って行なわれる場合、コンバータ制御手段３０２Ａの判定部３６Ａ、コンバータ制御手段３０２Ｂの判定部３６Ｂおよびコンバータ制御手段３０２Ｃの判定部３６Ｃは、電流ＩＬＥをしきい値と比較し、交流部において漏電が発生したか否かを判定する機能を有する。
【０２４７】
負荷駆動装置１００Ａの全体動作は、負荷駆動装置１００の全体動作のうち、漏電検出器７０により交流部における漏電を検出する動作を漏電検出器８０および判定部３６Ｄにより漏電を検出する動作に代えたものであり、その他は、負荷駆動装置１００の全体動作と同じである。
【０２４８】
なお、漏電検出器８０および判定部３６Ｄは、「漏電検出装置」を構成する。
その他は、実施の形態１と同じである。
【０２４９】
［実施の形態３］
図１９は、実施の形態３による負荷駆動装置の概略ブロック図である。図１９を参照して、負荷駆動装置１００Ｂは、負荷駆動装置１００の制御装置３０を制御装置３０Ｂに代え、漏電検出器８０を追加したものであり、その他は、負荷駆動装置１００と同じである。
【０２５０】
漏電検出器８０については、上述したとおりである。
制御装置３０Ｂは、制御装置３０の機能に追加して、電流センサー８３からの電流ＩＬＥをしきい値と比較し、負荷駆動装置１００Ｂの交流部において漏電が発生したか否かを判定する機能を有する。
【０２５１】
制御装置３０Ｂは、コンバータ制御手段３０２に代えて図２０に示すコンバータ制御手段３０２Ｅを含む。図２０は、コンバータ制御手段のさらに他の機能ブロック図である。
【０２５２】
図２０を参照して、コンバータ制御手段３０２Ｅは、コンバータ制御手段３０２の判定部３６を判定部３６Ｅに代えたものであり、その他は、コンバータ制御手段３０２と同じである。
【０２５３】
判定部３６Ｅは、電流センサー８３から電流ＩＬＥを受け、その受けた電流ＩＬＥがしきい値よりも大きいか否かを判定し、電流ＩＬＥがしきい値よりも大きいとき、交流部において漏電が発生したと判定する。そして、判定部３６Ｅは、電流ＩＬＥに基づいて交流部において漏電が発生したと判定したとき、または漏電検出器７０から信号ＤＥＬを受けたとき、信号ＣＴＬを生成して電圧指令演算部３３へ出力する。
【０２５４】
判定部３６Ｅは、その他は、判定部３６と同じ機能を果たす。
負荷駆動装置１００Ｂは、２つの漏電検出器７０，８０を備える。そして、漏電検出器８０は、上述したように漏電検出器７０が検出可能な漏電電流よりも小さい漏電電流を検出する。つまり、漏電検出器８０は、漏電検出器７０よりも漏電電流を検出する感度が高い。したがって、負荷駆動装置１００Ｂは、感度が異なる２つの漏電検出器７０，８０を備える。
【０２５５】
これにより、負荷駆動装置１００Ｂにおいては、広い範囲の漏電電流を検出できる。
【０２５６】
負荷駆動装置１００Ｂにおける漏電発生時に漏電電流を抑制する動作は、図７〜図９、図１２、図１４および図１５のいずれかに示すフローチャートに従って行なわれる。
【０２５７】
負荷駆動装置１００Ｂにおける漏電発生時に漏電電流を抑制する動作が図８、図９、図１２、図１４および図１５のいずれかに示すフローチャートに従って行なわれる場合、コンバータ制御手段３０２Ａの判定部３６Ａ、コンバータ制御手段３０２Ｂの判定部３６Ｂおよびコンバータ制御手段３０２Ｃの判定部３６Ｃは、電流ＩＬＥをしきい値と比較し、交流部において漏電が発生したか否かを判定する機能を有する。
【０２５８】
負荷駆動装置１００Ｂの全体動作は、負荷駆動装置１００の全体動作のうち、漏電検出器８０および判定部３６Ｄにより漏電を検出する動作およびその漏電検出に応じて降圧動作を行なうように昇圧コンバータ１１を制御する動作を追加したものであり、その他は、負荷駆動装置１００の全体動作と同じである。
【０２５９】
その他は、実施の形態１，２と同じである。
なお、上述した実施の形態１〜３においては、交流モータは１つであるとして説明したが、この発明は、これに限らず、交流モータは複数であってもよい。この場合、複数のモータに対応して複数のインバータがコンデンサ１２の両端に並列に接続される。そして、複数のモータのうち、少なくとも１つのモータにおいて漏電が発生した場合、昇圧コンバータ１１の降圧動作によりインバータ２０側における直流電圧Ｖｍの電圧レベルを低下させても良いし、漏電が発生していないモータを力行モードで駆動してインバータ２０側における直流電圧Ｖｍの電圧レベルを低下させても良い。
【０２６０】
また、上述した実施の形態１〜３においては、漏電検出器７０，８０が漏電を検出すると、降圧動作を行なうように昇圧コンバータ１１を制御すると説明したが、この発明は、これに限らず、漏電検出器７０，８０が漏電を検出すると、昇圧動作を中止するように昇圧コンバータ１１を制御するものであればよい。昇圧コンバータ１１の昇圧動作を中止させることにより、インバータ２０側における直流電圧Ｖｍの上昇を防止して漏電電流を抑制できるからである。
【０２６１】
そして、この昇圧動作の中止は、漏電検出時の直流電圧Ｖｍの電圧レベルを保持することと、直流電圧Ｖｍを低下させることとの両方を含む概念である。直流電圧Ｖｍの電圧レベルを保持する制御は、昇圧コンバータ１１の電圧指令Ｖｄｃ＿ｃｏｍを漏電検出時の直流電圧Ｖｍに設定してＮＰＮトランジスタＱ１をスイッチング制御し、ＮＰＮトランジスタＱ２をオフ制御することにより実現される。
【０２６２】
さらに、インバータ２０は、「直流／交流変換器」を構成する。
実施の形態１〜３において説明した負荷駆動装置１００，１００Ａ，１００Ｂは、ハイブリッド自動車または電気自動車に搭載され、ハイブリッド自動車または電気自動車の駆動輪を駆動する。
【０２６３】
たとえば、負荷駆動装置１００，１００Ａ，１００Ｂがハイブリッド自動車に搭載された場合、交流モータＭ１は、２つのモータジェネレータＭＧ１，ＭＧ２からなる。そして、モータジェネレータＭＧ１は、動力分割機構を介してエンジンに連結され、エンジンを始動するとともに、エンジンの回転力により発電する。また、モータジェネレータＭＧ２は、動力分割機構を介して前輪（駆動輪）に連結され、前輪を駆動するとともに、前輪の回転力により発電する。
【０２６４】
負荷駆動装置１００，１００Ａ，１００Ｂが電気自動車に搭載された場合、交流モータＭ１は、前輪（駆動輪）に連結され、前輪を駆動するとともに前輪の回転力により発電する。
【０２６５】
そして、負荷駆動装置１００，１００Ａ，１００Ｂは、ハイブリッド自動車または電気自動車の走行中および停車中において、交流部における漏電を検出し、昇圧コンバータ１１の昇圧動作中に漏電を検出した場合、上述した方法によってインバータ２０側における直流電圧Ｖｍを低下させる。
【０２６６】
したがって、負荷駆動装置１００，１００Ａ，１００Ｂを搭載したハイブリッド自動車または電気自動車においては、漏電が発生しても漏電電流を抑制できる。
【０２６７】
今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は、上記した実施の形態の説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。
【図面の簡単な説明】
【図１】実施の形態１による負荷駆動装置の概略ブロック図である。
【図２】図１に示す制御装置の機能のうち、昇圧コンバータおよびインバータの制御に関わる機能を示す機能ブロック図である。
【図３】図２に示すインバータ制御手段の機能ブロック図である。
【図４】図２に示すコンバータ制御手段の機能ブロック図である。
【図５】図１に示すインピーダンス判定回路の機能ブロック図である。
【図６】漏電が発生したときの等価回路を示す回路図である。
【図７】図１に示す負荷駆動装置における漏電発生時に漏電電流を抑制する動作を説明するためのフローチャートである。
【図８】図１に示す負荷駆動装置における漏電発生時に漏電電流を抑制する動作を説明するための他のフローチャートである。
【図９】図１に示す負荷駆動装置における漏電発生時に漏電電流を抑制する動作を説明するためのさらに他のフローチャートである。
【図１０】コンバータ制御手段の他の機能ブロック図である。
【図１１】保護デューティー比のオンデューティーとインバータ側における直流電圧との関係を示す図である。
【図１２】図１に示す負荷駆動装置における漏電発生時に漏電電流を抑制する動作を説明するためのさらに他のフローチャートである。
【図１３】コンバータ制御手段のさらに他の機能ブロック図である。
【図１４】図１に示す負荷駆動装置における漏電発生時に漏電電流を抑制する動作を説明するためのさらに他のフローチャートである。
【図１５】図１に示す負荷駆動装置における漏電発生時に漏電電流を抑制する動作を説明するためのさらに他のフローチャートである。
【図１６】コンバータ制御手段のさらに他の機能ブロック図である。
【図１７】実施の形態２による負荷駆動装置の概略ブロック図である。
【図１８】コンバータ制御手段のさらに他の機能ブロック図である。
【図１９】実施の形態３による負荷駆動装置の概略ブロック図である。
【図２０】コンバータ制御手段のさらに他の機能ブロック図である。
【符号の説明】
１０，１６ 電圧センサー、１１ 昇圧コンバータ、１２，８２ コンデンサ、１３ ＤＣ／ＤＣコンバータ、１４ エアコン、１５ カップリングコンデンサ、１７，２４，８３ 電流センサー、２０ インバータ、２１ Ｕ相アーム、２２ Ｖ相アーム、２３ Ｗ相アーム、２５，２７ 抵抗成分、２６ キャパシタンス成分、３０，３０Ａ，３０Ｂ 制御装置、３１ モータ制御用相電圧演算部、３２ インバータ用ＰＷＭ信号変換部、３３，３３Ａ 電圧指令演算部、３４，３４Ａ コンバータ用デューティー比演算部、３５ コンバータ用ＰＷＭ信号変換部、３６，３６Ａ，３６Ｂ，３６Ｃ，３６Ｄ，３６Ｅ 判定部、３７ 演算部、４０ 発振回路、６０ インピーダンス判定回路、７０，８０ 漏電検出器、８１ スイッチ、１００，１００Ａ，１００Ｂ 負荷駆動装置、３０１ インバータ制御手段、３０２，３０２Ａ，３０２Ｂ，３０２Ｃ，３０２Ｄ，３０２Ｅ コンバータ制御手段、６０１〜６０３，６２０ ノイズフィルター、６０４〜６０６，６２１ バンドパスフィルター、６０７〜６０９，６２２ ピークホールド回路、６１０〜６１２，６２３ 波高値抽出回路、６１３ 判定回路、Ｎ１，Ｎ２，Ｎ３ ノード、Ｂ１，Ｂ２ 直流電源、Ｌ１ リアクトル、Ｑ１〜Ｑ８ ＮＰＮトランジスタ、Ｄ１〜Ｄ８ ダイオード、ＳＲ１，ＳＲ２ システムリレー。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a load drive device for a hybrid vehicle and an electric vehicle, and more particularly, a load drive device having a countermeasure function when a leakage occurs, a vehicle equipped with the load drive device, and a control when the leakage occurs in the load drive device. The present invention relates to a computer-readable recording medium on which a program for recording is recorded.
[0002]
[Prior art]
Recently, hybrid vehicles and electric vehicles have attracted a great deal of attention as environmentally friendly vehicles. Some hybrid vehicles have been put into practical use.
[0003]
This hybrid vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source in addition to a conventional engine. In other words, a power source is obtained by driving the engine, a DC voltage from a DC power source is converted into an AC voltage by an inverter, and a motor is rotated by the converted AC voltage to obtain a power source. An electric vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source.
[0004]
Therefore, such a hybrid vehicle and an electric vehicle are equipped with an electric system for driving wheels, and it is considered to detect whether or not a leakage has occurred in the electric system. For example, Japanese Patent Application Laid-Open No. 7-241022 discloses a leakage detector disposed between a battery and an inverter that drives a motor by converting a DC voltage from the battery into an AC voltage. This leakage detector detects a leakage of the motor on the input side of the inverter.
[0005]
[Patent Document 1]
JP 7-24002 A
[0006]
[Patent Document 2]
Japanese Patent Laid-Open No. 10-337039
[0007]
[Patent Document 3]
JP 2002-218656 A
[0008]
[Problems to be solved by the invention]
However, the technique disclosed in Japanese Patent Application Laid-Open No. 7-24102 simply shuts down the current supplied to the inverter when a leakage current is detected in the electric system that drives the motor by converting the DC voltage from the battery into an AC voltage. Is. Therefore, in an electric system provided with a boost converter for boosting a DC voltage from a power source between the power source and the inverter, when a motor leakage occurs during the boost operation of the boost converter, it is disclosed in Japanese Patent Application Laid-Open No. 7-241022. However, there is a problem that appropriate leakage countermeasures cannot be achieved with this technology.
[0009]
That is, when the technique disclosed in Japanese Patent Application Laid-Open No. 7-241022 is applied to an electric system including a boost converter, the voltage between the boost converter and the inverter increases, and the capacitor provided on the input side of the inverter is damaged. There is a problem.
[0010]
Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a load driving device capable of taking appropriate countermeasures against electric leakage in an electric system including a boost converter.
[0011]
Another object of the present invention is to provide an automobile equipped with a load driving device capable of taking appropriate measures against electric leakage in an electric system including a boost converter.
[0012]
Furthermore, another object of the present invention is to provide a computer-readable recording medium on which a program for causing a computer to execute control when leakage occurs in a load driving device including a boost converter.
[0013]
[Means for Solving the Problems and Effects of the Invention]
According to this invention, the load driving device includes a voltage converter, a leakage detection device, and a control device. The voltage converter boosts the first DC voltage supplied from the power source to the second DC voltage and supplies it to the load side, and steps down the second DC voltage to the first DC voltage to supply the power Step-down operation is performed. The leakage detection device detects a load leakage. The control device controls the voltage converter to stop the boosting operation when the leakage detection device detects a leakage of the load during the boosting operation of the voltage converter.
[0014]
In the load driving device according to the present invention, if the leakage in the load is detected during the voltage converter boosting operation, the second DC voltage on the load side does not increase.
[0015]
Therefore, according to the present invention, the leakage current can be suppressed.
Moreover, according to this invention, a load drive apparatus is provided with a voltage converter, an electrical leakage detection apparatus, and a control apparatus. The voltage converter boosts the first DC voltage supplied from the power source to the second DC voltage and supplies it to the load side, and steps down the second DC voltage to the first DC voltage to supply the power Step-down operation is performed. The leakage detection device detects a load leakage. The control device controls the voltage converter to perform a step-down operation when the leakage detection device detects a load leakage during the step-up operation of the voltage converter.
[0016]
In the load driving device according to the present invention, when leakage in the load is detected during the voltage converter boosting operation, the second DC voltage on the load side is stepped down and supplied to the power supply. Then, the second DC voltage decreases.
[0017]
Therefore, according to the present invention, the leakage current can be suppressed.
Preferably, the load driving device further includes a DC / AC converter. The DC / AC converter is arranged between the voltage converter and the load. The power source is a direct current. The load is alternating current.
[0018]
The DC / AC converter performs conversion between DC and AC between the voltage converter and the load.
[0019]
Therefore, according to the present invention, the leakage current flowing through the DC / AC converter can be suppressed.
[0020]
Preferably, the voltage converter includes an upper arm and a lower arm connected in series. When the leakage detection device detects load leakage, the control device performs switching control on the upper arm and turns off the lower arm.
[0021]
The upper arm repeats on / off, supplies a direct current from the load side to the power supply side during the on period, and steps down the second direct current voltage to the first direct current voltage.
[0022]
Therefore, according to the present invention, the leakage current can be easily suppressed.
Preferably, the control device performs switching control of the upper arm at a protection duty ratio in which a direct current flowing through the upper arm is smaller than an overcurrent of the upper arm.
[0023]
The upper arm supplies a direct current smaller than the overcurrent from the load side to the power supply side to step down the second direct current voltage to the first direct current voltage.
[0024]
Therefore, according to the present invention, the leakage current can be suppressed while protecting the upper arm.
[0025]
Preferably, the control device performs switching control of the upper arm at the protection duty ratio until the second DC voltage drops to a predetermined voltage, and turns on the upper arm when the second DC voltage drops to the predetermined voltage. The predetermined voltage is a voltage at which the direct current flowing through the upper arm is smaller than the overcurrent.
[0026]
The upper arm is repeatedly turned on / off until the second DC voltage reaches a predetermined voltage, and supplies a DC current smaller than an overcurrent from the load side to the power source side during the ON period, thereby supplying the second DC voltage to the second arm. Step down to a DC voltage of 1. Then, when the second DC voltage becomes a predetermined voltage, the upper arm supplies a DC current from the load side to the power supply side until the second DC voltage becomes the power supply voltage.
[0027]
Therefore, according to the present invention, the leakage current can be suppressed to the maximum while protecting the upper arm.
[0028]
Preferably, the load driving device further includes a voltage sensor. The voltage sensor detects the second DC voltage. The control device holds a map indicating the relationship between the second DC voltage and the protection duty ratio, extracts the protection duty ratio corresponding to the second DC voltage detected by the voltage sensor from the map, The upper arm is subjected to switching control with the extracted protection duty ratio.
[0029]
A protection duty ratio corresponding to the detected second DC voltage is extracted based on a relationship between a predetermined protection duty ratio and the second DC voltage. Then, the upper arm repeatedly turns on / off based on the extracted protection duty ratio, and supplies a second direct current voltage from the load side to the power source side during the on period by supplying a direct current smaller than the overcurrent to the first power source. Step down to DC voltage.
[0030]
Therefore, according to the present invention, it is possible to suppress the leakage current while accurately protecting the upper arm even when the voltage level of the second DC voltage varies.
[0031]
Preferably, the protection duty ratio includes an on-duty that is inversely proportional to the second DC voltage.
[0032]
The upper arm supplies a direct current from the load side to the power supply side for a relatively short period when the second DC voltage is relatively high, and is relatively long when the second DC voltage becomes relatively low. During the period, a direct current is supplied from the load side to the power supply side to step down the second direct current voltage to the first direct current voltage. That is, the upper arm supplies a current amount corresponding to the voltage level of the second DC voltage from the load side to the power supply side to step down the second DC voltage to the first DC voltage.
[0033]
Therefore, according to the present invention, it is possible to suppress the leakage current while accurately protecting the upper arm even when the voltage level of the second DC voltage varies.
[0034]
Preferably, the voltage converter includes an upper arm and a lower arm connected in series. When the leakage detection device detects load leakage, the control device turns on the upper arm and turns off the lower arm.
[0035]
The upper arm supplies a DC current from the load side to the power supply side until the second DC voltage becomes the power supply voltage.
[0036]
Therefore, according to the present invention, the leakage current can be suppressed to the maximum.
Preferably, the voltage converter includes an upper arm and a lower arm connected in series. When the leakage detection device detects the leakage of the load, the control device performs switching control on the upper arm until the second DC voltage drops to a predetermined voltage, and controls the lower arm to turn off, so that the second DC voltage is When the voltage drops to a predetermined voltage, the upper arm is turned off. The predetermined voltage is a voltage when the voltage difference between the second DC voltage and the first DC voltage becomes a predetermined value.
[0037]
The upper arm repeats on / off to step down the second DC voltage, and stops the step-down operation when the second DC voltage becomes a predetermined voltage higher than the first DC voltage.
[0038]
Therefore, according to the present invention, the leakage current suppressing operation period can be shortened.
Preferably, the leakage detection device includes a node, an oscillation circuit, and a determination circuit. The node is connected to the ground line of the power supply via a coupling capacitor. The oscillation circuit oscillates an AC signal on which a plurality of frequencies are superimposed. The determination circuit detects an AC signal from the oscillation circuit via the node, and determines whether or not a leakage has occurred in the load based on the peak value in each frequency component of the detected AC signal.
[0039]
Therefore, according to the present invention, the leakage in the load can be accurately detected.
Preferably, the leakage detection device includes a capacitor, a switch, a current sensor, and a determination circuit. The capacitor is connected between the load and the ground line. The switch is connected between the load and the capacitor. The current sensor detects a current flowing through the earth line through the capacitor. The determination circuit determines whether or not a leakage has occurred in the load based on the current value from the current sensor. The control device further periodically turns on / off the switch.
[0040]
The leakage current in the load is actually detected periodically, and the occurrence of leakage in the load is detected based on the detected leakage current.
[0041]
Therefore, according to the present invention, it is possible to accurately detect electric leakage.
Preferably, the leakage detection device includes a first leakage detector and a second leakage detector. The second leakage detector detects a smaller leakage than the first leakage detector. The first leakage detector includes a node, an oscillation circuit, and a first determination circuit. The node is connected to the ground line of the power supply via a coupling capacitor. The oscillation circuit oscillates an AC signal on which a plurality of frequencies are superimposed. The first determination circuit detects an AC signal from the oscillation circuit via a node, and determines whether or not a leakage has occurred in the load based on the peak value in each frequency component of the detected AC signal.
[0042]
The second leakage detector includes a capacitor, a switch, a current sensor, and a second determination circuit. The capacitor is connected between the load and the ground line. The switch is connected between the load and the capacitor. The current sensor detects a current flowing through the earth line through the capacitor. The second determination circuit determines whether or not a leakage has occurred in the load based on the current value from the current sensor. Then, the control device further turns the switch on and off periodically, and when the first leakage detector or the second leakage detector detects the leakage of the load, the voltage is set so that the voltage converter performs a step-down operation. Control the transducer.
[0043]
The leakage in the load is detected by the two leakage detectors having different sensitivities.
Therefore, according to the present invention, the leakage can be detected in a wide range of the leakage current.
[0044]
Preferably, the voltage converter supplies the stepped down first DC voltage to the auxiliary machine when the capacity of the power source is a full charge amount.
[0045]
Therefore, according to the present invention, the leakage current can be suppressed while protecting the power supply.
Moreover, according to this invention, a motor vehicle is a motor vehicle carrying the load drive device of any one of Claims 1-14.
[0046]
Therefore, according to the present invention, the leakage current in the automobile can be suppressed.
Furthermore, according to the present invention, a computer-readable recording medium storing a program for causing a computer to execute is recorded on a computer-readable recording medium storing a program for causing the computer to execute control when leakage occurs in the load driving device. It is a recording medium. The load driving device includes a voltage converter and a leakage detection device. The voltage converter boosts the first DC voltage supplied from the power source to the second DC voltage and supplies it to the load side, and steps down the second DC voltage to the first DC voltage to supply the power Step-down operation is performed. The leakage detection device detects a load leakage.
[0047]
The program includes a first step for determining whether or not a leakage of the load is detected by the leakage detection device during the step-up operation of the voltage converter, and a voltage conversion so as to perform a step-down operation when the leakage of the load is detected. A computer-readable recording medium recording a program for causing the computer to execute the second step of controlling the device.
[0048]
When the program detects a leakage in the load, the program controls the voltage converter to perform a step-down operation.
[0049]
Therefore, according to the present invention, the leakage current can be suppressed.
Preferably, the voltage converter includes an upper arm and a lower arm connected in series. The second step of the program includes a first sub-step for controlling the lower arm to be turned off and a second sub-step for controlling the switching of the upper arm.
[0050]
The program turns off the lower arm and turns the upper arm on / off. Then, during the ON period, the upper arm supplies a direct current from the load side to the power supply side to step down the second direct current voltage.
[0051]
Therefore, according to the present invention, control for suppressing the leakage current can be easily performed.
[0052]
Preferably, the second sub-step includes a step A for determining a protection duty ratio in which a direct current flowing through the upper arm is smaller than an overcurrent of the upper arm, and a step B for performing switching control of the upper arm with the protection duty ratio. Including.
[0053]
The program determines a protection duty ratio for flowing a direct current smaller than the overcurrent to the upper arm, and turns on / off at the determined protection duty ratio. Then, the upper arm supplies a direct current smaller than the overcurrent from the load side to the power supply side to step down the second direct current voltage.
[0054]
Therefore, according to the present invention, it is possible to perform control for suppressing the leakage current while protecting the upper arm.
[0055]
Preferably, the second sub-step further includes a step C of turning on the upper arm when the second DC voltage drops to a predetermined voltage.
[0056]
The program continues to turn on the upper arm when the second DC voltage reaches a predetermined voltage. Then, the upper arm supplies a direct current smaller than the overcurrent from the load side to the power supply side to step down a predetermined voltage to the power supply voltage.
[0057]
Therefore, according to the present invention, it is possible to perform control for suppressing the leakage current to the maximum while protecting the upper arm.
[0058]
Preferably, in step A, the step of detecting the second DC voltage and the protection duty ratio corresponding to the detected second DC voltage are referred to a map showing the relationship between the second DC voltage and the protection duty ratio. And extracting.
[0059]
When the program detects the second DC voltage, the program extracts a protection duty ratio corresponding to the detected second DC voltage from a map indicating the relationship between the predetermined second DC voltage and the protection duty ratio.
[0060]
Therefore, according to the present invention, even if the voltage level of the second DC voltage fluctuates, it is possible to perform control for suppressing the leakage current while protecting the upper arm.
[0061]
Preferably, the protection duty ratio includes an on-duty that is inversely proportional to the second DC voltage.
[0062]
The program turns on the upper arm for a relatively short period when the second DC voltage is relatively high, and turns on the upper arm for a relatively long period when the second DC voltage decreases relatively . That is, the program controls the upper arm so as to supply a current amount corresponding to the voltage level of the second DC voltage from the load side to the power supply side.
[0063]
Therefore, according to the present invention, even if the voltage level of the second DC voltage fluctuates, it is possible to perform control for suppressing the leakage current while protecting the upper arm.
[0064]
Preferably, the voltage converter includes an upper arm and a lower arm connected in series. The second step of the program includes a first sub-step for turning off the lower arm and a second sub-step for turning on the upper arm.
[0065]
When the program detects a leakage in the load, it turns off the lower arm and keeps the upper arm on.
[0066]
Therefore, according to the present invention, it is possible to perform control for suppressing the leakage current to the maximum.
[0067]
Preferably, the voltage converter includes an upper arm and a lower arm connected in series. The second step of the program includes a first sub-step for controlling the lower arm to turn off, and a second sub-step for controlling the switching of the upper arm so that the second DC voltage drops to a predetermined voltage. Including.
[0068]
When the program detects a leakage in the load, it turns off the lower arm and turns the upper arm on / off. Then, the upper arm steps down the second DC voltage to a predetermined voltage higher than the first DC voltage.
[0069]
Therefore, according to the present invention, the control period for suppressing the leakage current can be shortened.
Preferably, the leakage detection device includes a first leakage detector and a second leakage detector. The second leakage detector detects a smaller leakage than the first leakage detector.
[0070]
The first leakage detector includes a node, an oscillation circuit, and a first determination circuit. The node is connected to the ground line of the power supply via a coupling capacitor. The oscillation circuit oscillates an AC signal on which a plurality of frequencies are superimposed. The first determination circuit detects an AC signal from the oscillation circuit via a node, and determines whether or not a leakage has occurred in the load based on the peak value in each frequency component of the detected AC signal.
[0071]
The second leakage detector includes a capacitor, a switch, a current sensor, and a second determination circuit. The capacitor is connected between the load and the ground line. The switch is connected between the load and the capacitor. The current sensor detects a current flowing through the earth line through the capacitor. The second determination circuit determines whether or not a leakage has occurred in the load based on the current value from the current sensor.
[0072]
The first step of the program is the step of periodically turning on / off the switch, the step of determining whether or not the first leakage detector has detected the leakage of the load, and the second leakage detector is the load Determining whether or not an electrical leakage has been detected.
[0073]
The program periodically turns on the first leakage detector. Then, the program determines whether at least one of the two leakage detectors having different sensitivities has detected a leakage in the load.
[0074]
Therefore, according to the present invention, it is possible to detect a leakage in the load in a wide range of the leakage current.
[0075]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.
[0076]
[Embodiment 1]
FIG. 1 is a schematic block diagram of a load driving device according to the first embodiment. Referring to FIG. 1, load drive apparatus 100 according to Embodiment 1 of the present invention includes DC power supplies B1, B2, system relays SR1, SR2, voltage sensors 10, 16, boost converter 11, capacitor 12, , DC / DC converter 13, air conditioner 14, current sensors 17, 24, inverter 20, control device 30, and leakage detector 70.
[0077]
Boost converter 11 includes a reactor L1, NPN transistors Q1, Q2, and diodes D1, D2. Reactor L1 has one end connected to the power supply line of DC power supply B1 and the other end connected to the intermediate point between NPN transistor Q1 and NPN transistor Q2, that is, between the emitter of NPN transistor Q1 and the collector of NPN transistor Q2. Connected.
[0078]
NPN transistors Q1 and Q2 are connected in series between the power supply line of inverter 20 and the ground line. NPN transistor Q1 has a collector connected to the power supply line and an emitter connected to the collector of NPN transistor Q2. NPN transistor Q2 has an emitter connected to the ground line.
[0079]
Further, diodes D1 and D2 for flowing current from the emitter side to the collector side are connected between the collector and emitter of each NPN transistor Q1 and Q2.
[0080]
Inverter 20 includes a U-phase arm 21, a V-phase arm 22, and a W-phase arm 23. U-phase arm 21, V-phase arm 22, and W-phase arm 23 are provided in parallel between the power supply line and the earth line.
[0081]
U-phase arm 21 includes NPN transistors Q3 and Q4 connected in series, V-phase arm 22 includes NPN transistors Q5 and Q6 connected in series, and W-phase arm 23 includes NPN transistors connected in series. It consists of transistors Q7 and Q8. Further, diodes D3 to D8 that flow current from the emitter side to the collector side are connected between the collectors and emitters of the NPN transistors Q3 to Q8, respectively.
[0082]
An intermediate point of each phase arm is connected to each phase end of each phase coil of AC motor M1. In other words, AC motor M1 is a three-phase permanent magnet motor, and is configured such that one end of three coils of U, V, and W phases is commonly connected to the middle point, and the other end of the U-phase coil is NPN transistor Q3. The other end of the V-phase coil is connected to the intermediate point of NPN transistors Q5 and Q6, and the other end of the W-phase coil is connected to the intermediate point of NPN transistors Q7 and Q8, respectively.
[0083]
Leakage detector 70 includes a coupling capacitor 15, an oscillation circuit 40, a resistor 50, and an impedance determination circuit 60. Coupling capacitor 15 connects the negative side of DC power supply B1 (ie, the ground line) to node N1. The resistor 50 is connected between the node N1 and the oscillation circuit 40.
[0084]
DC / DC converter 13 and air conditioner 14 are connected in parallel to nodes N2 and N3 between system relays SR1 and SR2 and boost converter 11. The DC power source B2 is connected to the DC / DC converter 13.
[0085]
The DC power source B1 is composed of a secondary battery such as nickel metal hydride or lithium ion. DC power supply B1 supplies a DC voltage to boost converter 11, DC / DC converter 13 and air conditioner 14 via system relays SR1 and SR2.
[0086]
System relays SR1 and SR2 are turned on / off by a signal SE from control device 30. More specifically, system relays SR1 and SR2 are turned on by H (logic high) level signal SE from control device 30, and are turned off by L (logic low) level signal SE from control device 30.
[0087]
Voltage sensor 10 detects DC voltage Vb output from DC power supply B <b> 1 and outputs the detected DC voltage Vb to control device 30.
[0088]
The current sensor 17 detects a DC current BCRT input / output to / from the DC power supply B <b> 1 and outputs the detected DC current BCRT to the control device 30.
[0089]
Boost converter 11 boosts the DC voltage from DC power supply B <b> 1 based on signal PWMU from control device 30 and supplies the boosted voltage to capacitor 12. Further, boost converter 11 steps down the DC voltage supplied from inverter 20 based on signal PWMD or PWML from control device 30 and supplies it to DC power supply B 1 or DC / DC converter 13 and air conditioner 14.
[0090]
Capacitor 12 smoothes the DC voltage supplied from boost converter 11 and supplies it to inverter 20.
[0091]
The DC / DC converter 13 converts the voltage level of the DC voltage received from the DC power supply B1 or the boost converter 11 and supplies it to the DC power supply B2. Air conditioner 14 is driven by a DC voltage received from DC power supply B <b> 1 or boost converter 11.
[0092]
The voltage sensor 16 detects the voltage Vm across the capacitor 12 and outputs the detected voltage Vm to the control device 30.
[0093]
Inverter 20 converts the DC voltage supplied from boost converter 11 via capacitor 12 into an AC voltage based on signal PWMI from control device 30 to drive AC motor M1. Further, inverter 20 converts the AC voltage generated by AC motor M1 into a DC voltage based on signal PWMC from control device 30 and supplies the converted DC voltage to boost converter 11 via capacitor 12.
[0094]
Current sensor 24 detects motor current MCRT flowing through AC motor M <b> 1 and outputs the detected motor current MCRT to control device 30.
[0095]
The control device 30 sets the DC voltage Vb from the voltage sensor 10, the voltage Vm from the voltage sensor 16, the motor rotational speed MRN and the torque command value TR from an ECU (Electrical Control Unit) provided outside the load driving device 100. Based on this, signal PWMU or signal PWMD is generated by a method described later, and the generated signal PWMU or signal PWMD is output to boost converter 11.
[0096]
Further, when control device 30 receives DEL indicating that a leakage has occurred in the AC section of load driving device 100 from leakage detector 70, control device 30 controls boost converter 11 to perform a step-down operation by a method described later. The signal PWML is generated, and the generated signal PWML is output to the boost converter 11. That is, control device 30 controls boost converter 11 to suppress the leakage current when a leakage occurs in the AC unit of load drive device 100.
[0097]
Further, based on voltage Vm from voltage sensor 16, motor current MCRT from current sensor 24, and torque command value TR from external ECU, control device 30 generates signal PWMI or signal PWMC by a method described later, The generated signal PWMI or signal PWMC is output to the inverter 20.
[0098]
Further, when control device 30 receives signal DEL from leakage detector 70 while boost converter 11 is performing an operation other than the boost operation, a display device (not shown) indicates that leakage has occurred in AC motor M1. To display.
[0099]
The oscillation circuit 40 has an AC signal E on which three frequencies are superimposed. ₀ And the oscillated AC signal E ₀ Is output to the node N1 through the resistor 50. For example, the oscillation circuit 40 outputs an AC signal E0 on which three frequencies f1, f2, and f3 (f1 <f2 <f3) selected from frequencies in the range of 0.1 Hz to 10 kHz are superimposed. The oscillation circuit 40 has a configuration in which a ring oscillator that oscillates an AC signal of frequency f1, a ring oscillator that oscillates an AC signal of frequency f2, and a ring oscillator that oscillates an AC signal of frequency f3 are connected to one node. Consists of.
[0100]
The impedance determination circuit 60 is connected to the AC signal E output from the oscillation circuit 40. ₀ Is received via the node N1, the received AC signal E is separated into frequency components, and the peak values of the separated frequency components are detected. Based on the detected three peak values, the impedance determination circuit 60 determines whether or not a leakage has occurred in the AC unit of the inverter 20 and the AC motor M1 from the DC power source B1 to the inverter 20 by a method described later. It is determined whether or not a leakage has occurred in the direct current section. When the impedance determination circuit 60 determines that a leakage has occurred in the AC unit, the impedance determination circuit 60 generates a signal DEL indicating that a leakage has occurred in the AC unit and outputs the signal DEL to the control device 30.
[0101]
FIG. 2 is a functional block diagram showing functions related to control of boost converter 11 and inverter 20 among the functions of control device 30 shown in FIG. Referring to FIG. 2, control device 30 includes inverter control means 301 and converter control means 302. Based on torque command value TR, motor current MCRT, and voltage Vm (corresponding to “inverter input voltage” to inverter 20; the same applies hereinafter), inverter control means 301 generates signal PWMI or signal PWMC by a method described later. And output to the NPN transistors Q3 to Q8 of the inverter 20.
[0102]
Converter control means 302 generates signal PWMU or signal PWMD based on torque command value TR, motor rotational speed MRN, DC voltage Vb and voltage Vm, and outputs them to NPN transistors Q1 and Q2 of boost converter 11. To do. In addition, when converter control means 302 receives signal DEL from leakage detector 70, it generates signal PWML and outputs it to NPN transistors Q1 and Q2 of boost converter 11.
[0103]
FIG. 3 is a functional block diagram of the inverter control means 301 shown in FIG. Referring to FIG. 3, inverter control means 301 includes a motor control phase voltage calculation unit 31 and an inverter PWM signal conversion unit 32.
[0104]
The motor control phase voltage calculation unit 31 receives the inverter input voltage Vm to the inverter 20 from the voltage sensor 16, receives the motor current MCRT flowing in each phase of the AC motor M1 from the current sensor 24, and receives the torque command value TR from the external ECU. Receive from. The motor control phase voltage calculation unit 31 calculates the voltage to be applied to the coils of each phase of the AC motor M1 based on these input signals, and the calculated result is the inverter PWM signal conversion unit 32. Output to.
[0105]
Based on the calculation result received from motor control phase voltage calculation unit 31, inverter PWM signal conversion unit 32 generates signal PWMI or signal PWMC that actually turns on / off each NPN transistor Q3-Q8 of inverter 20. Then, the generated signal PWMI or signal PWMC is output to each of the NPN transistors Q3 to Q8.
[0106]
Thereby, each NPN transistor Q3-Q8 is switching-controlled, and controls the electric current sent through each phase of AC motor M1 so that AC motor M1 outputs the commanded torque. In this way, the motor drive current is controlled, and a motor torque corresponding to the torque command value TR is output.
[0107]
Whether the operation mode of AC motor M1 is the power running mode or the regeneration mode is determined by the relationship between torque command value TR and motor rotational speed MRN. In a Cartesian coordinate system, when the horizontal axis is the motor rotation speed MRN and the vertical axis is the torque command value TR, the AC motor has a relationship between the torque command value TR and the motor rotation speed MRN in the first and second quadrants. The operation mode of M1 is the power running mode, and when the relationship between the torque command value TR and the motor rotation speed MRN exists in the third and fourth quadrants, the operation mode of the AC motor M1 is the regeneration mode.
[0108]
Therefore, when receiving a positive torque command value TR, the inverter control means 301 generates a signal PWMI for driving the AC motor M1 as a drive motor and outputs the signal PWMI to the NPN transistors Q3 to Q8, and the negative torque command value TR. If it receives, the signal PWMC for driving the AC motor M1 in the regeneration mode is generated and output to the NPN transistors Q3 to Q8.
[0109]
FIG. 4 is a functional block diagram of converter control means 302 shown in FIG. Referring to FIG. 4, converter control means 302 includes a voltage command calculation unit 33, a converter duty ratio calculation unit 34, a converter PWM signal conversion unit 35, and a determination unit 36.
[0110]
Voltage command calculation unit 33 calculates the optimum value (target value) of the inverter input voltage, that is, voltage command Vdc_com of boost converter 11 based on torque command value TR and motor rotation speed MRN from the external ECU, and calculates Voltage command Vdc_com is output to converter duty-ratio calculation unit 34.
[0111]
Further, when receiving the signal CTL from the determination unit 36, the voltage command calculation unit 33 calculates a voltage command Vdc_com_lk for stepping down the voltage Vm received from the voltage sensor 16 to a predetermined voltage Vref1, and the calculated voltage command Vdc_com_lk. Is output to the converter duty-ratio calculation unit 34.
[0112]
The converter duty ratio calculation unit 34 determines the voltage Vm based on the voltage command Vdc_com or Vdc_com_lk from the voltage command calculation unit 33, the DC voltage Vb from the voltage sensor 10, and the voltage Vm from the voltage sensor 16. The duty ratio for setting to Vdc_com or Vdc_com_lk is calculated, and the calculated duty ratio is output to the converter PWM signal converter 35.
[0113]
When converter duty-ratio calculation unit 34 receives signal STP from determination unit 36, converter duty-ratio calculation unit 34 sets the duty cycle of NPN transistor Q1 to 0% regardless of voltage command Vdc_com or Vdc_com_lk from voltage command calculation unit 33. The ratio is calculated and output to the converter PWM signal converter 35.
[0114]
Converter PWM signal converter 35 receives signal PWMU (or signal PWMD or signal PWML) for turning on / off NPN transistors Q1 and Q2 of boost converter 11 based on the duty ratio from converter duty ratio calculator 34. The generated signal PWMU (or signal PWMD or signal PWML) is output to NPN transistors Q1 and Q2 of boost converter 11.
[0115]
When determining unit 36 receives signal DEL from leakage detector 70, based on torque command value TR and motor rotational speed MRN, determination unit 36 determines whether the operating motor of AC motor M1 is in the power running mode or the regenerative mode based on the method described above. When the operating motor of the AC motor M1 is in the power running mode, it is determined that the boost converter 11 is in the boosting operation. When the operating motor of the AC motor M1 is in the regenerative mode, the boost converter 11 is in the step-down operation. It is determined that When determining that boost converter 11 is performing a boost operation, determination unit 36 generates signal CTL and outputs the signal CTL to voltage command calculation unit 33. When determining that boost converter 11 is performing a step-down operation, AC motor A signal LKE indicating that a leakage has occurred in M1 is generated and output to a display device (not shown).
[0116]
In addition, the determination unit 36 generates the signal CTL and outputs the signal CTL to the voltage command calculation unit 33, and then determines whether or not the voltage Vm from the voltage sensor 16 is equal to the DC voltage Vb from the voltage sensor 10. Is equal to the DC voltage Vb, the signal STP is generated and output to the converter duty ratio calculation unit 34. When the voltage Vm is higher than the DC voltage Vb, the signal CTL is generated and output to the voltage command calculation unit 33. .
[0117]
Further, the determination unit 36 generates the signal CTL and outputs the signal CTL to the voltage command calculation unit 33, and then determines whether or not the voltage Vm from the voltage sensor 16 is equal to or lower than the predetermined voltage Vref1. When the voltage Vref1 or less, the signal STP is generated and output to the converter duty ratio calculation unit 34. When the voltage Vm is higher than the predetermined voltage Vref1, the signal CTL is generated and output to the voltage command calculation unit 33. .
[0118]
Note that increasing the on-duty of the NPN transistor Q2 on the lower side of the boost converter 11 increases the power storage in the reactor L1, so that a higher voltage output can be obtained. On the other hand, increasing the on-duty of the upper NPN transistor Q1 reduces the voltage of the power supply line. Therefore, by controlling the duty ratio of the NPN transistors Q1 and Q2, the voltage of the power supply line can be controlled to an arbitrary voltage higher than the output voltage of the DC power supply B1.
[0119]
Converter control means 302 generates signal PWMU for boosting DC voltage Vb when the operation mode of AC motor M1 is the powering mode, and reduces voltage Vm when the operation mode of AC motor M1 is the regeneration mode. The signal PWMD is generated.
[0120]
These signal PWMU and signal PWMD are generated based on torque command value TR and motor rotation speed MRN from the external ECU. That is, signal PWMU is generated when AC motor M1 is in the power running mode and boost converter 11 performs the boost operation, and signal PWMD is generated when AC motor M1 is in the regeneration mode and boost converter 11 performs the step-down operation. Is generated.
[0121]
Further, converter control means 302 receives signal DEL from leakage detector 70 and generates signal PWML for controlling boost converter 11 to perform the step-down operation when it is determined that step-up converter 11 is performing the step-up operation. To do. Therefore, signal PWML is generated regardless of torque command value TR from external ECU and motor rotational speed MRN, and is a signal for forcibly switching the operation of boost converter 11 from the boost operation to the step-down operation.
[0122]
When a leakage occurs in the AC unit of the load driving device 100 during the boost operation of the boost converter 11, the operation of the boost converter 11 is forcibly switched from the boost operation to the step-down operation by the signal PWML. Vm can be reduced and the leakage current can be suppressed.
[0123]
FIG. 5 is a functional block diagram of the impedance determination circuit 60 shown in FIG. Referring to FIG. 5, impedance determination circuit 60 includes noise filters 601 to 603, bandpass filters 604 to 606, peak hold circuits 607 to 609, peak value extraction circuits 610 to 612, and determination circuit 613. Including.
[0124]
The noise filters 601 to 603 receive the AC signal E via the node N1, cut the noise of the received AC signal E, and output it to the handpass filters 604 to 606, respectively.
[0125]
The band-pass filter 604 cuts the AC signal having the frequencies f2 and f3 from the AC signal E, and transmits only the AC signal having the frequency f1 to the peak hold circuit 607. Further, the band pass filter 605 cuts the AC signals of the frequencies f1 and f3 from the AC signal E and transmits only the AC signal of the frequency f2 to the peak hold circuit 608. Further, the band pass filter 606 cuts the AC signals of the frequencies f1 and f2 from the AC signal E and transmits only the AC signal of the frequency f3 to the peak hold circuit 609.
[0126]
The peak hold circuit 607 holds the peak value of the AC signal having the frequency f1, and outputs the hold signal HD1 to the peak value extraction circuit 610. The peak hold circuit 608 holds the peak value of the AC signal having the frequency f2, and outputs the hold signal HD2 to the peak value extraction circuit 611. Further, the peak hold circuit 609 holds the peak value of the AC signal having the frequency f3 and outputs the hold signal HD3 to the peak value extraction circuit 612.
[0127]
The peak value extraction circuit 610 extracts the peak value H1 of the AC signal having the frequency f1 based on the hold signal HD1 and outputs the extracted peak value H1 to the determination circuit 613. Further, the peak value extraction circuit 611 extracts the peak value H2 of the AC signal having the frequency f2 based on the hold signal HD2, and outputs the extracted peak value H2 to the determination circuit 613. Further, the peak value extraction circuit 612 extracts the peak value H3 of the AC signal having the frequency f3 based on the hold signal HD3, and outputs the extracted peak value H3 to the determination circuit 613.
[0128]
Judgment circuit 613 is based on the peak values H1 to H3 received from peak value extraction circuits 610 to 612, and whether or not there is a leakage in the AC unit such as AC motor M1 or whether there is a leakage in the DC unit from DC power supply B1 to inverter 20. Determine.
[0129]
First, the determination method of the presence or absence of the electric leakage in an alternating current part is demonstrated. In the present invention, when leakage occurs in the AC part of the inverter 20 and the AC motor M1, the leakage impedance corresponds to the impedance in which the resistance component 25 and the capacitance component 26 are connected in parallel. When a leakage occurs in the AC unit, the AC signal E output from the oscillation circuit 40 is displayed. ₀ Is transmitted through the resistor 50, the coupling capacitor 15, the impedance of the resistance component 25 and the capacitance component 26 connected in parallel (hereinafter referred to as “leakage impedance”, the same applies hereinafter), and the path of the ground line GND. Therefore, assuming that the leakage impedance is Z, the equivalent circuit when leakage occurs is the circuit shown in FIG. The power supply V outputs an AC voltage having one of the frequencies f1, f2, and f3. The resistance value of the resistor 50 is R1, the capacitance of the coupling capacitor 15 is C1, and the earth leakage impedance Z is that the capacitor C2 and the resistor R2 are connected in parallel.
[0130]
Then, the total impedance Z0 of the equivalent circuit shown in FIG. 6 is obtained by connecting the resistor R1, the capacitor C1, and the leakage impedance Z in series, but the voltage Vn at the node N1 indicates whether or not leakage occurs, that is, Since it is greatly affected by the leakage impedance Z, the resistor R1 and the capacitor C1 are taken into consideration by the resistor R2 and the capacitor C2 that constitute the leakage impedance Z.
[0131]
Therefore, the total impedance Z0 is
[0132]
[Expression 1]

[0133]
It becomes.
Then, the voltage Vn is
[0134]
[Expression 2]

[0135]
It becomes.
As a result, the voltage Vn decreases as the frequency f of the voltage V increases, and increases as the frequency f decreases. That is, the voltage Vn changes as the frequency f of the voltage V varies. This corresponds to the fact that the peak values H1 to H3 received by the determination circuit 613 from the peak value extraction circuits 610 to 612 change as the frequency changes. Therefore, the determination circuit 613 determines that a leakage has occurred in the AC unit if the peak values H1 to H3 received from the peak value extraction circuits 610 to 612 are fluctuating.
[0136]
Further, if no leakage occurs in the AC section, the voltage Vn depends only on the resistor R1. That is, when there is no leakage, the voltage Vn is constant even if the frequency f of the voltage V varies. This corresponds to the fact that the crest values H1 to H3 received by the determination circuit 613 from the crest value extraction circuits 610 to 612 do not change as the frequency changes. Therefore, the determination circuit 613 determines that no leakage has occurred in the AC unit unless the peak values H1 to H3 received from the peak value extraction circuits 610 to 612 have changed.
[0137]
Next, a method for determining the presence or absence of electric leakage in the DC unit will be described. When a leakage occurs in the DC part from the DC power supply B 1 to the inverter 20, the leakage impedance Z corresponds to the impedance composed of the resistance component 27. When a leakage occurs in the direct current section, the alternating current signal E output from the oscillation circuit 40 is displayed. ₀ Is transmitted through the resistor 50, the coupling capacitor 15, the earth leakage impedance Z composed of the resistor component 27, and the path of the ground line GND. Therefore, the equivalent circuit in the case where a leakage occurs in the direct current portion corresponds to a circuit in which the leakage impedance Z of the circuit shown in FIG.
[0138]
Assuming that the resistance value of the resistance component 27 is the resistance R2, the total impedance Z0 of the equivalent circuit shown in FIG. 6 is the resistance R1, the capacitance C1, and the resistance resistance R2 connected in series, but the voltage Vn at the node N1 is Since the value of the total impedance Z greatly depends on the resistance R2, since it is greatly influenced by whether or not the leakage occurs, that is, the fluctuation of the leakage impedance Z (that is, the resistance R2).
[0139]
Thus, when leakage occurs in the direct current section, it is the resistance component 27 that greatly affects the total impedance Z0. Therefore, when leakage occurs in the direct current section, the voltage Vn at the node N1 is It is constant even if the frequency fluctuates.
[0140]
This corresponds to the fact that the peak values H1 to H3 received by the determination circuit 613 from the peak value extraction circuits 610 to 612 do not change as the frequency changes. Therefore, if the peak values H1 to H3 received from the peak value extraction circuits 610 to 612 have not changed, the determination circuit 613 determines whether or not the received peak values H1 to H3 are smaller than the reference value. Then, the determination circuit 613 determines that a leakage has occurred in the direct current portion when the peak values H1 to H3 are larger than the reference value, and a leakage has occurred in the direct current portion when the peak values H1 to H3 are smaller than the reference value. Judge that it is not.
[0141]
The determination circuit 613 generates a signal DEL and outputs the signal DEL to the control device 30 when it is determined by the above-described method that a leakage has occurred in the AC unit.
[0142]
In the following, the control in the load driving device 100 when a leakage occurs in the AC unit will be described.
[0143]
FIG. 7 is a flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving apparatus 100 shown in FIG. Referring to FIG. 7, when a series of operations is started, leakage detector 70 generates signal DEL and outputs it to control device 30 when the occurrence of leakage in the AC unit is detected by the method described above. Determination unit 36 of converter control means 302 determines whether or not a leakage has occurred by determining whether or not signal DEL has been received from leakage detector 70 (step S1). When it is determined in step S1 that a leakage has occurred, the determination unit 36 determines whether or not the boost converter 11 is performing a boost operation by the method described above (step S2). Then, when determining that boost converter 11 is not performing a boost operation, determination unit 36 generates signal LKE and outputs the signal LKE to a display device (not shown). In response to the signal LKE, the display device turns on a warning lamp indicating that electric leakage has occurred in the AC unit (step S3). Thereafter, a series of operations ends.
[0144]
On the other hand, when it is determined in step S <b> 2 that boost converter 11 is performing a boost operation, determination unit 36 generates signal CTL and outputs the signal CTL to voltage command calculation unit 33. The voltage command calculation unit 33 calculates a voltage command Vdc_com_lk1 (a kind of voltage command Vdc_com_lk) composed of the DC voltage Vb from the voltage sensor 10 in accordance with the signal CTL from the determination unit 36 and supplies the voltage command Vdc_com_lk to the converter duty ratio calculation unit 34. Output.
[0145]
Based on the voltage command Vdc_com_lk1 (= Vb) from the voltage command calculation unit 33, the DC voltage Vb from the voltage sensor 10, and the voltage Vm from the voltage sensor 16, the converter duty ratio calculation unit 34 performs the above-described method. The duty ratio DR1 for stepping down the voltage Vm to the DC voltage Vb is calculated, and the calculated duty ratio DR1 is output to the converter PWM signal converter 35.
[0146]
Then, converter PWM signal converter 35 generates signal PWML1 (a type of signal PWML) by the above-described method based on duty ratio DR1 from converter duty ratio calculator 34, and boosts the generated signal PWML1. Output to NPN transistors Q1 and Q2 of converter 11.
[0147]
This signal PWML1 is a signal for keeping the NPN transistor Q1 on and turning off the NPN transistor Q2. Therefore, converter PWM signal converter 35 outputs signal PWML1 to NPN transistors Q1 and Q2, whereby NPN transistor Q2 is turned off and NPN transistor Q1 is turned on (steps S4 and S5).
[0148]
Then, NPN transistor Q2 is turned off in response to signal PWML1, and NPN transistor Q1 is turned on in response to signal PWML1. Boost converter 11 then supplies the DC current on capacitor 12 side to DC power supply B1 side to step down voltage Vm to DC voltage Vb (also referred to as “power supply voltage”).
[0149]
Then, determination unit 36 of converter control means 302 determines whether or not voltage Vm from voltage sensor 16 matches DC voltage Vb from voltage sensor 10 (step S6), and voltage Vm matches DC voltage Vb. When not, a signal CTL is generated and output to the voltage command calculation unit 33. Then, steps S4 to S6 are repeatedly executed.
[0150]
On the other hand, when it is determined in step S6 that the voltage Vm matches the DC voltage Vb, the determination unit 36 generates a signal STP and outputs the signal STP to the converter duty ratio calculation unit 34. When converter duty-ratio calculation unit 34 receives signal STP from determination unit 36, converter duty-ratio calculation unit 34 calculates a duty ratio in which the on-duty of NPN transistor Q1 is set to 0%, and outputs the result to converter PWM signal conversion unit 35. Then, converter PWM signal converter 35 generates a signal for turning off NPN transistor Q1, and outputs the signal to NPN transistor Q1. That is, converter control means 302 controls off NPN transistor Q1 (step S7). Thereafter, the series of operations ends.
[0151]
The flowchart shown in FIG. 7 is a flowchart in which the DC voltage Vm on the inverter 20 side is stepped down to the power supply voltage Vb and supplied to the DC power supply B1 when a leakage occurs in the AC section. Therefore, the converter control means 302 turns on the NPN transistor Q1 so as to step down the DC voltage Vm on the inverter 20 side to the power supply voltage Vb and supply it to the DC power supply B1 when a leakage occurs in the AC section of the load driving device 100. Control. As a result, the DC voltage Vm on the inverter 20 side decreases to the power supply voltage Vb, so that the leakage current can be suppressed to the maximum.
[0152]
The operation of suppressing the leakage current when leakage occurs in the load driving device 100 may be performed according to the flowchart shown in FIG. FIG. 8 is another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device 100 shown in FIG.
[0153]
The flowchart shown in FIG. 8 is the same as the flowchart shown in FIG. 7 except that steps S5 and S6 in the flowchart shown in FIG. 7 are replaced with steps S5A and S6A, respectively. Referring to FIG. 8, when it is determined in step S2 that boost converter 11 is performing a boosting operation, voltage command calculation unit 33 calculates voltage command Vdc_com_lk2 (a kind of voltage command Vdc_com_lk) composed of predetermined voltage Vref1. And output to the converter duty-ratio calculation unit 34. The predetermined voltage Vref1 is higher than the power supply voltage Vb and lower than the DC voltage Vm.
[0154]
The converter duty-ratio calculation unit 34 is based on the voltage command Vdc_com_lk2 (= Vref1) from the voltage command calculation unit 33, the DC voltage Vb from the voltage sensor 10, and the voltage Vm from the voltage sensor 16 according to the method described above. The duty ratio DR2 for stepping down the voltage Vm to the predetermined voltage Vref1 is calculated, and the calculated duty ratio DR2 is output to the converter PWM signal converter 35.
[0155]
Then, converter PWM signal conversion unit 35 generates signal PWML2 (a kind of signal PWML) by the above-described method based on duty ratio DR2 from converter duty ratio calculation unit 34, and boosts the generated signal PWML2 Output to NPN transistors Q1 and Q2 of converter 11.
[0156]
This signal PWML2 is a signal for switching the NPN transistor Q1 and continuing to turn off the NPN transistor Q2. Therefore, converter PWM signal conversion unit 35 outputs signal PWML2 to NPN transistors Q1 and Q2, whereby OFF control of NPN transistor Q2 and switching control of NPN transistor Q1 are performed (steps S4 and S5A).
[0157]
Then, NPN transistor Q2 is turned off according to signal PWML2, and NPN transistor Q1 is switched according to signal PWML2. Boost converter 11 supplies the DC current on the capacitor 12 side to DC power supply B1 side during the on period of NPN transistor Q1 to step down voltage Vm to a predetermined voltage Vref1.
[0158]
Then, determination unit 36 of converter control means 302 determines whether or not voltage Vm from voltage sensor 16 is equal to or lower than predetermined voltage Vref1 (step S6A), and generates signal CTL when voltage Vm is not equal to or lower than predetermined voltage Vref1. And output to the voltage command calculation unit 33. Steps S4, S5A, and S6A are repeatedly executed.
[0159]
On the other hand, when it is determined in step S6A that the voltage Vm is equal to or lower than the predetermined voltage Vref1, the determination unit 36 generates a signal STP and outputs the signal STP to the converter duty ratio calculation unit 34. Thereafter, the above-described operation is performed.
[0160]
The predetermined voltage Vref1 is a voltage when the voltage difference between the DC voltage Vm and the power supply voltage Vb becomes a predetermined value. For example, the predetermined voltage Vref1 is set to 250V when the power supply voltage Vb is 210V. At this time, the predetermined value is 40V. Therefore, the boost converter 11 is stopped when the DC voltage Vm is stepped down to 250V.
[0161]
The flowchart shown in FIG. 8 is a flowchart in which the DC voltage Vm on the inverter 20 side is stepped down to a predetermined voltage Vref1 by the switching operation of the NPN transistor Q1 and supplied to the DC power supply B1 when a leakage occurs in the AC section. Therefore, when leakage occurs in the AC section during the boosting operation of boost converter 11, converter control means 302 reduces the DC voltage Vm on the inverter 20 side to a predetermined voltage Vref1 and supplies it to DC power supply B1. The transistor Q1 is subjected to switching control.
[0162]
As a result, the DC voltage Vm on the inverter 20 side decreases to the predetermined voltage Vref1, and the leakage current in the AC section can be suppressed.
[0163]
In the flowchart shown in FIG. 8, when the DC voltage Vm on the inverter 20 side is stepped down to a predetermined voltage Vref1 higher than the power supply voltage Vb, the step-down operation of the step-up converter 11 is stopped (see steps S6A and S7). ), The period during which the leakage current is suppressed can be shortened.
[0164]
The operation of suppressing the leakage current when leakage occurs in the load driving device 100 may be performed according to the flowchart shown in FIG. When the operation of suppressing the leakage current when leakage occurs in load drive device 100 is performed according to the flowchart shown in FIG. 9, control device 30 includes converter control means 302 </ b> A shown in FIG. 10 instead of converter control means 302.
[0165]
FIG. 10 is another functional block diagram of the converter control means. Referring to FIG. 10, converter control means 302A replaces voltage command calculation section 33 of converter control means 302 with voltage command calculation section 33A, converts converter duty ratio calculation section 34 with converter duty ratio calculation section 34A, The determination unit 36 is replaced with the determination unit 36A, and the other parts are the same as those of the converter control unit 302.
[0166]
When voltage signal calculation unit 33A receives signal CTL1 from determination unit 36A, voltage command calculation unit 33A calculates voltage command Vdc_com_lk31 (a kind of voltage command Vdc_com_lk) for stepping down DC voltage Vm to predetermined voltage Vref2, and converter duty ratio calculation unit To 34A.
[0167]
The predetermined voltage Vref2 is a voltage when a DC current smaller than an overcurrent flows through the NPN transistor Q1 even if the on-duty of the NPN transistor Q1 is set to 100%, that is, even if the NPN transistor Q1 is kept on. It is.
[0168]
Further, upon receiving the signal CTL2 from the determination unit 36A, the voltage command calculation unit 33A calculates a voltage command Vdc_com_lk32 (a kind of voltage command Vdc_com_lk) for stepping down the DC voltage Vm to the power supply voltage Vb to calculate the converter duty ratio. To the unit 34A.
[0169]
The voltage command calculation unit 33 </ b> A performs the same functions as the voltage command calculation unit 33.
The converter duty-ratio calculation unit 34A is referred to as a duty ratio DR3 (referred to as “protection duty ratio”) for flowing a direct current smaller than the overcurrent to the NPN transistor Q1 in response to the voltage command Vdc_com_lk31 from the voltage command calculation unit 33A. ) And output to the converter PWM signal converter 35.
[0170]
Further, converter duty-ratio calculation unit 34A calculates duty ratio DR1 for stepping down DC voltage Vm to power supply voltage Vb in accordance with voltage command Vdc_com_lk32 from voltage command calculation unit 33A, and converter PWM signal conversion unit To 35.
[0171]
Converter duty-ratio calculation unit 34A performs the same functions as converter duty-ratio calculation unit 34.
[0172]
The determination unit 36A determines whether the boost converter 11 is performing a step-up operation or a step-down operation by the same method as the determination unit 36. When it is determined that the step-up operation is being performed, the determination unit 36A generates a signal CTL1 and outputs the signal CTL1 To do.
[0173]
The determination unit 36A determines whether or not the voltage Vm from the voltage sensor 16 is equal to or lower than a predetermined voltage Vref2 after outputting the signal CTL1 to the voltage command calculation unit 33A. Then, the determination unit 36A generates a signal CTL1 when the voltage Vm is higher than the predetermined voltage Vref2 and outputs the signal CTL1 to the voltage command calculation unit 33A, and generates a signal CTL2 when the voltage Vm is equal to or lower than the predetermined voltage Vref2. It outputs to the voltage command calculating part 33A.
[0174]
The determination unit 36A performs the same function as the determination unit 36 in addition.
FIG. 9 is still another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device 100 shown in FIG. The flowchart shown in FIG. 9 is the same as the flowchart shown in FIG. 7 except that steps S4 to S6 in the flowchart shown in FIG. 7 are replaced with steps S10 to S15.
[0175]
Referring to FIG. 9, when it is determined in step S2 that boost converter 11 is performing a boost operation, determination unit 36A generates signal CTL1 and outputs it to voltage command calculation unit 33A. Voltage command calculation unit 33A calculates voltage command Vdc_com_lk31 including predetermined voltage Vref2 in accordance with signal CTL1 from determination unit 36A, and outputs the voltage command to converter duty ratio calculation unit 34A.
[0176]
Based on the voltage command Vdc_com_lk31 (= Vref2) from the voltage command calculation unit 33A, the DC voltage Vb from the voltage sensor 10, and the voltage Vm from the voltage sensor 16, the converter duty ratio calculation unit 34A A duty ratio DR3 (protection duty ratio) for reducing the voltage Vm to a predetermined voltage Vref2 is calculated, and the calculated duty ratio DR3 is output to the converter PWM signal converter 35. That is, converter control means 302A determines the protection duty ratio (step S10).
[0177]
Then, converter PWM signal converter 35 generates signal PWML3 (a type of signal PWML) by the above-described method based on duty ratio DR3 from converter duty ratio calculator 34A, and boosts the generated signal PWML3. Output to NPN transistors Q1 and Q2 of converter 11.
[0178]
This signal PWML3 is a signal for switching the NPN transistor Q1 at the duty ratio DR3 (protection duty ratio) and keeping the NPN transistor Q2 off. Therefore, converter PWM signal conversion unit 35 outputs signal PWML3 to NPN transistors Q1 and Q2, so that NPN transistor Q2 is turned off and switching control is performed based on the protection duty ratio of NPN transistor Q1 (steps S11 and S12). .
[0179]
Then, NPN transistor Q2 is turned off according to signal PWML3, and NPN transistor Q1 is switched at a protection duty ratio according to signal PWML3. Then, during the ON period of NPN transistor Q1, boost converter 11 supplies a DC current on capacitor 12 side to DC power supply B1 side while passing a DC current smaller than the overcurrent to NPN transistor Q1, and supplies voltage Vm to a predetermined voltage. Step down to Vref2.
[0180]
Then, determination unit 36A of converter control means 302A determines whether or not voltage Vm from voltage sensor 16 is equal to or lower than predetermined voltage Vref2 (step S13), and generates signal CTL1 when voltage Vm is not equal to or lower than predetermined voltage Vref2. And output to the voltage command calculation unit 33A. Then, steps S10 to S13 are repeatedly executed.
[0181]
On the other hand, when it is determined in step S13 that the voltage Vm is equal to or lower than the predetermined voltage Vref2, the determination unit 36A generates a signal CTL2 and outputs the signal CTL2 to the voltage command calculation unit 33A. Voltage command calculation unit 33A calculates voltage command Vdc_com_lk32 in accordance with signal CTL2 and outputs it to converter duty ratio calculation unit 34A.
[0182]
Then, converter duty-ratio calculation unit 34A generates duty ratio DR1 described above in accordance with voltage command Vdc_com_lk32 and outputs the duty ratio DR1 to converter PWM signal conversion unit 35. Then, converter PWM signal converter 35 generates signal PWML1 based on duty ratio DR1 and outputs it to NPN transistors Q1 and Q2 of boost converter 11.
[0183]
As described above, the signal PWML1 is a signal for continuously turning on the NPN transistor Q1 and keeping the NPN transistor Q2 off. Therefore, converter PWM signal converter 35 outputs signal PWML1 to NPN transistors Q1 and Q2, so that NPN transistor Q2 is continuously turned off after being turned off in step S11, and ON control of NPN transistor Q1 is performed. (Step S14).
[0184]
Then, NPN transistor Q2 is continuously turned off according to signal PWML1, and NPN transistor Q1 is always turned on according to signal PWML1. Boost converter 11 then supplies the DC current on capacitor 12 side to DC power supply B1 side to step down voltage Vm to power supply voltage Vb.
[0185]
Then, determination unit 36A of converter control means 302A determines whether or not voltage Vm from voltage sensor 16 matches DC voltage Vb from voltage sensor 10 (step S15), and voltage Vm matches DC voltage Vb. When not, a signal CTL2 is generated and output to the voltage command calculation unit 33A. Steps S14 and S15 are repeatedly executed.
[0186]
On the other hand, when it is determined in step S15 that voltage Vm matches DC voltage Vb, determination unit 36A generates signal STP and outputs it to converter duty ratio calculation unit 34A. Thereafter, the above-described operation is performed.
[0187]
In the flowchart shown in FIG. 9, when a leakage occurs in the AC section, the DC voltage Vm on the inverter 20 side is switched to the predetermined voltage Vref2 by the switching operation of the NPN transistor Q1 while flowing a DC current smaller than the overcurrent to the NPN transistor Q1. When the DC voltage Vm is stepped down to a predetermined voltage Vref2, the NPN transistor Q1 is kept on and the DC voltage Vm is stepped down to the power supply voltage Vb. The predetermined voltage Vref2 is a voltage at which a direct current smaller than the overcurrent flows through the NPN transistor Q1 even if the NPN transistor Q1 is kept on.
[0188]
Therefore, when leakage occurs in the AC unit during the boosting operation of the boost converter 11, the converter control unit 302A applies the DC voltage Vm on the inverter 20 side to a predetermined voltage while flowing a DC current smaller than the overcurrent to the NPN transistor Q1. The NPN transistor Q1 is controlled so as to sequentially step down to the voltage Vref2 and the power supply voltage Vb.
[0189]
As a result, the DC voltage Vm on the inverter 20 side decreases to the power supply voltage Vb, and the leakage current in the AC section can be suppressed to the maximum while protecting the NPN transistor Q1.
[0190]
In this way, the converter control means 302A controls the NPN transistor Q1 so that a direct current smaller than the overcurrent flows to the NPN transistor Q1 and protects the NPN transistor Q1, while converting the DC voltage Vm on the inverter 20 side to the power supply voltage. Boost converter 11 is controlled so as to suppress the leakage current to the maximum by reducing the voltage to Vb.
[0191]
The converter duty ratio calculation unit 34A of the converter control means 302A calculates a duty ratio DR3 (protection duty ratio) for flowing a direct current smaller than the overcurrent to the NPN transistor Q1 according to the voltage command Vdc_com_lk31. The protection duty ratio changes depending on the voltage level of the DC voltage Vm when a leakage occurs. That is, when the voltage level of the DC voltage Vm when the leakage occurs is relatively high, the on-duty of the protection duty ratio becomes relatively small, and the voltage level of the DC voltage Vm when the leakage occurs is relatively On the other hand, the on-duty of the protection duty ratio becomes relatively large.
[0192]
More specifically, the overcurrent of the NPN transistor Q1 is Ilim, and the on-resistance of the NPN transistor Q1 is R _ON And the on-duty of the protection duty ratio is DR _ON Then, the following equation is established.
[0193]
[Equation 3]

[0194]
From equation (3), the on-duty DR of the protection duty ratio _ON Is inversely proportional to the DC voltage Vm on the inverter 20 side.
[0195]
FIG. 11 shows the on-duty DR of the protective duty ratio. _ON It is a figure which shows the relationship between DC voltage Vm in the inverter 20 side. A curve k1 indicates an on-duty DR for causing a DC current smaller than an overcurrent to flow through the NPN transistor Q1 when the DC voltage Vm is applied to the boost converter 11 from the capacitor 12 side. _ON And the DC voltage Vm. And on-duty DR _ON Is inversely proportional to the DC voltage Vm.
[0196]
The converter duty-ratio calculation unit 34A holds the map shown in FIG. 11 and receives the voltage command Vdc_com_lk31 from the voltage command calculation unit 33A, and the on-duty DR corresponding to the DC voltage Vm from the voltage sensor 16. _ON Are extracted from the map shown in FIG. Then, converter duty-ratio calculation unit 34A extracts the extracted on-duty DR. _ON Is used to calculate the protection duty ratio DR3, and the calculated protection duty ratio DR3 is output to the converter PWM signal converter 35.
[0197]
Therefore, in step S10 shown in FIG. 9, the on-duty DR corresponding to the DC voltage Vm detected by the voltage sensor 16 is referred to with reference to the map shown in FIG. _ON May be extracted to determine the protection duty ratio. On-duty DR _ON Is equivalent to the protection duty ratio DR3, the converter duty ratio calculation unit 34A holds a map indicating the relationship between the protection duty ratio DR3 and the DC voltage Vm, and the DC voltage detected by the voltage sensor 16 is The protection duty ratio corresponding to Vm may be extracted with reference to a map. In this case, the map showing the relationship between the protection duty ratio DR3 and the DC voltage Vm is the same curve as the curve k1 shown in FIG.
[0198]
Thus, when determining the protection duty ratio DR3 according to the map shown in FIG. 11, the on-duty of the NPN transistor Q1 is relatively short when the DC voltage Vm is relatively high, and the DC voltage Vm is relatively low. When it is low, it becomes relatively long.
[0199]
Therefore, since the on-duty of NPN transistor Q1 is determined according to the voltage level of DC voltage Vm so that the DC current flowing through NPN transistor Q1 is smaller than the overcurrent of NPN transistor Q1, the voltage level of DC voltage Vm is Even if it fluctuates, the leakage current can be suppressed while protecting the NPN transistor Q1.
[0200]
The operation of suppressing the leakage current when leakage occurs in the load driving device 100 may be performed according to the flowchart shown in FIG. When the operation of suppressing the leakage current when leakage occurs in load driving device 100 is performed according to the flowchart shown in FIG. 12, control device 30 includes converter control means 302 </ b> B shown in FIG. 13 instead of converter control means 302.
[0201]
FIG. 13 is still another functional block diagram of the converter control means. Referring to FIG. 13, converter control unit 302B is the same as converter control unit 302 except that determination unit 36 of converter control unit 302 is replaced with determination unit 36B and calculation unit 37 is added.
[0202]
Based on DC current BCRT from current sensor 17, operation unit 37 integrates the capacity SOC (Scale Of Charge) of DC power supply B1, and outputs the accumulated capacity SOC to determination unit 36B.
[0203]
Determination unit 36B determines whether or not the capacity SOC from calculation unit 37 has reached the full charge amount of DC power supply B1. Then, the determination unit 36B generates the signal CTL and the L-level signal SE when the capacity SOC reaches the full charge amount of the DC power supply B1, and outputs the generated signal CTL to the voltage command calculation unit 33. L level signal SE is output to system relays SR1 and SR2. Further, the determination unit 36B generates a signal CTL and outputs the signal CTL to the voltage command calculation unit 33 when the capacity SOC has not reached the full charge amount of the DC power supply B1.
[0204]
In addition, the determination unit 36B performs the same function as the determination unit 36.
FIG. 12 is still another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device 100 shown in FIG. The flowchart shown in FIG. 12 is the same as the flowchart shown in FIG. 7 except that steps S21 and S22 are inserted between steps S2 and S4 of the flowchart shown in FIG.
[0205]
Referring to FIG. 12, when it is determined in step S2 that boost converter 11 is performing a boost operation, determination unit 36B determines whether capacity SOC from calculation unit 37 has reached the full charge amount of DC power supply B1. If the capacity SOC has not reached the full charge amount of the DC power supply B1, a signal CTL is generated and output to the voltage command calculation unit 33. Then, steps S4 to S7 described above are executed.
[0206]
On the other hand, when it is determined in step S21 that the capacity SOC has reached the full charge amount of DC power supply B1, determination unit 36B generates L-level signal SE and outputs it to system relays SR1 and SR2. Then, system relays SR1 and SR2 are turned off by L level signal SE (step S22). Thereafter, steps S4 to S7 described above are executed, and step-up converter 11 steps down DC voltage Vm to power supply voltage Vb and supplies it to DC / DC converter 13 and air conditioner 14. DC / DC converter 13 converts the voltage level of the DC voltage from boost converter 11 to charge DC power supply B2. Air conditioner 14 is driven by a DC voltage from boost converter 11. Others are as described above.
[0207]
The flowchart shown in FIG. 12 determines whether or not the capacity SOC of the DC power supply B1 has reached the full charge amount when a leakage occurs in the AC unit of the load driving device 100 during the boost operation of the boost converter 11. When the capacity SOC of the power supply B1 reaches the full charge amount, the DC voltage Vm is stepped down to the power supply voltage Vb and supplied to the DC / DC converter 13 and the air conditioner 14, and the capacity SOC of the DC power supply B1 reaches the full charge amount. If not, the DC voltage Vm is stepped down to the power supply voltage Vb and supplied to the DC power supply B1.
[0208]
Thereby, the leakage current can be suppressed to the maximum while protecting the DC power supply B1.
The operation of suppressing the leakage current when leakage occurs in the load driving device 100 may be performed according to the flowchart shown in FIG. When the operation of suppressing the leakage current when leakage occurs in load driving device 100 is performed according to the flowchart shown in FIG. 14, control device 30 includes converter control means 302 </ b> B shown in FIG. 13 instead of converter control means 302.
[0209]
FIG. 14 is still another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device 100 shown in FIG. The flowchart shown in FIG. 14 is the same as the flowchart shown in FIG. 8 except that steps S21 and S22 are inserted between steps S2 and S4 of the flowchart shown in FIG.
[0210]
Steps S21 and S22 are as described in FIG.
The flowchart shown in FIG. 14 determines whether or not the capacity SOC of the DC power source B1 has reached the full charge amount when a leakage occurs in the AC unit of the load driving device 100 during the boosting operation of the boost converter 11. When the capacity SOC of the power supply B1 reaches the full charge amount, the DC voltage Vm is stepped down to a predetermined voltage Vref1 and supplied to the DC / DC converter 13 and the air conditioner 14, and the capacity SOC of the DC power supply B1 is full charge amount. If not, the direct current voltage Vm is stepped down to a predetermined voltage Vref1 and supplied to the direct current power supply B1.
[0211]
Thereby, the leakage current can be suppressed while protecting the DC power supply B1. In addition, the operation period for suppressing the leakage current can be shortened.
[0212]
The operation of suppressing the leakage current when leakage occurs in the load driving device 100 may be performed according to the flowchart shown in FIG. When the operation of suppressing the leakage current when leakage occurs in load drive device 100 is performed according to the flowchart shown in FIG. 15, control device 30 includes converter control means 302 </ b> C shown in FIG. 16 instead of converter control means 302.
[0213]
FIG. 16 is still another functional block diagram of the converter control means. Referring to FIG. 16, converter control means 302C is the same as converter control means 302A except that calculation unit 37 is added instead of determination unit 36A of converter control unit 302A.
[0214]
The calculation unit 37 is as described above. The determination unit 36C determines whether or not the capacity SOC from the calculation unit 37 has reached the full charge amount of the DC power supply B1, and generates the signal CTL1 when the capacity SOC has not reached the full charge amount of the DC power supply B1. And output to the voltage command calculation unit 33A. Further, the determination unit 36C generates the signal CTL1 and the L level signal SE when the capacity SOC reaches the full charge amount of the DC power supply B1, and outputs the generated signal CTL1 to the voltage command calculation unit 33A. The generated L level signal SE is output to system relays SR1 and SR2.
[0215]
The determination unit 36C performs the same functions as the determination units 36 and 36A.
FIG. 15 is still another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device 100 shown in FIG. The flowchart shown in FIG. 15 is the same as the flowchart shown in FIG. 9 except that steps S21 and S22 are inserted between step S2 and step S10 of the flowchart shown in FIG.
[0216]
Steps S21 and S22 are as described in FIG.
The flow chart shown in FIG. 15 determines whether or not the capacity SOC of the DC power supply B1 has reached the full charge amount when a leakage occurs in the AC unit of the load driving device 100 during the boost operation of the boost converter 11. When the capacity SOC of the power supply B1 reaches the full charge amount, the DC voltage Vm is stepped down to the predetermined voltage Vref2 and the power supply voltage Vb sequentially while protecting the NPN transistor Q1, and supplied to the DC / DC converter 13 and the air conditioner 14. When the capacity SOC of the DC power supply B1 does not reach the full charge level, the DC voltage Vm is stepped down to the predetermined voltage Vref2 and the power supply voltage Vb and supplied to the DC power supply B1 while protecting the NPN transistor Q1. It is.
[0217]
Thereby, the leakage current can be suppressed to the maximum while protecting the DC power supply B1 and the NPN transistor Q1.
[0218]
As described above, the present invention is characterized in that the boost converter 11 is controlled to perform the step-down operation when a leakage occurs in the AC section of the load driving device 100 during the step-up operation of the step-up converter 11 ( (See steps S4 to S6 in FIGS. 7 and 12, steps S4, S5A, and S6A in FIGS. 8 and 14, and steps S10 to S15 in FIGS. 9 and 15).
[0219]
With this feature, the DC voltage Vm on the inverter 20 side is stepped down, and the leakage current can be suppressed.
[0220]
The operation of suppressing the leakage current in converter control means 302 is actually executed by a CPU (Central Processing Unit), and the CPU is in any one of FIGS. 7 to 9, 12, 14, and 15. A load driving device is read out from a ROM (Read Only Memory), and the read program is executed in accordance with the flowchart shown in any of FIGS. 7 to 9, 12, 14, and 15. Control to suppress the leakage current at 100 is performed.
[0221]
Therefore, the ROM corresponds to a computer (CPU) readable recording medium in which a program for performing control for suppressing the leakage current in the load driving device 100 is recorded.
[0222]
AC motor M1 constitutes a “load”.
Furthermore, DC power supply B2, DC / DC converter 13 and air conditioner 14 constitute an “auxiliary machine”.
[0223]
With reference to FIG. 1 again, the overall operation of the load driving device 100 will be described. When a series of operations is started, control device 30 receives torque command value TR and motor rotation speed MRN from the external ECU. Then, control device 30 generates H level signal SE and outputs it to system relays SR1 and SR2. Further, the control device 30 performs the above-described method based on the DC voltage Vb from the voltage sensor 10, the voltage Vm from the voltage sensor 16, the motor current MCRT from the current sensor 24, the torque command value TR, and the motor rotational speed MRN. Signals PWMU and PWMI for controlling boost converter 11 and inverter 20 are generated and output to boost converter 11 and inverter 20, respectively, such that AC motor M1 generates torque specified by torque command value TR.
[0224]
DC power supply B1 outputs a DC voltage, and system relays SR1 and SR2 supply the DC voltage to boost converter 11.
[0225]
Then, NPN transistors Q1 and Q2 of boost converter 11 are turned on / off in accordance with signal PWMU from control device 30 to convert the DC voltage into output voltage Vm and supply it to capacitor 12.
[0226]
Capacitor 12 smoothes the DC voltage supplied from boost converter 11 and supplies it to inverter 20. NPN transistors Q3 to Q8 of inverter 20 are turned on / off in accordance with signal PWMI from control device 30, inverter 20 converts a DC voltage into an AC voltage, and AC motor M1 converts the torque specified by torque command value TR. A predetermined alternating current is passed through each of the U-phase, V-phase, and W-phase of AC motor M1 so as to be generated. Thereby, AC motor M1 generates torque specified by torque command value TR.
[0227]
When the hybrid vehicle or electric vehicle on which the load driving device 100 is mounted enters the regenerative braking mode, the control device 30 is based on the DC voltage Vb, the voltage Vm, the motor current MCRT, the torque command value TR, and the motor rotational speed MRN. , Signals PWMC and PWMD are generated and output to inverter 20 and boost converter 11, respectively.
[0228]
AC motor M <b> 1 generates an AC voltage and supplies the generated AC voltage to inverter 20. Then, inverter 20 converts an AC voltage into a DC voltage in accordance with signal PWMC from control device 30, and supplies the converted DC voltage to boost converter 11 via capacitor 12.
[0229]
Boost converter 11 steps down the DC voltage according to signal PWMD from control device 30 and supplies the voltage to DC power supply B1 to charge DC power supply B1.
[0230]
Then, when the load driving device 100 is driving the AC motor M1, the leakage detector 70 generates a signal DEL indicating that leakage has occurred in the AC unit when detecting leakage in the AC unit by the above-described method. And output to the control device 30.
[0231]
Then, control device 30 determines whether or not the leakage is detected during the boost operation of boost converter 11, and when it is determined that the leakage is detected during the boost operation of boost converter 11, as described above. In addition, the boost converter 11 is controlled to perform the step-down operation.
[0232]
Control device 30 generates signal LKE and outputs it to a display device (not shown) when it is determined that leakage has been detected during step-down operation of step-up converter 11. Then, the display device turns on the warning lamp in response to the signal LKE.
[0233]
Thereby, when a leakage is detected during the boosting operation of boost converter 11, DC voltage Vm on inverter 20 side is stepped down, so that the leakage current can be suppressed.
[0234]
[Embodiment 2]
FIG. 17 is a schematic block diagram of the load driving device according to the second embodiment. Referring to FIG. 17, load drive device 100 </ b> A is obtained by replacing control device 30 of load drive device 100 with control device 30 </ b> A and replacing leakage detector 70 with leakage detector 80. The same as 100.
[0235]
Leakage detector 80 includes a switch 81, a capacitor 82, and a current sensor 83. Switch 81 and capacitor 82 are connected in series between one end of the W-phase coil of AC motor M1 and ground line GND. In this case, the switch 81 is connected to the AC motor M1 side, and the capacitor 82 is connected to the ground line GND side. The current sensor 83 is installed on the wiring between the capacitor 82 and the ground line GND.
[0236]
The switch 81 is periodically turned on / off by a signal SW from the control device 30A. Capacitor 82 has a capacity capable of detecting a leakage current smaller than the leakage current detectable by leakage detector 70 in the first embodiment. When the switch 81 is turned on by the signal SW, the current sensor 83 detects the current ILE and outputs the detected current ILE to the control device 30A.
[0237]
The control device 30A generates a signal SW for periodically turning on / off the switch 81 and outputs the signal SW to the switch 81. Control device 30A receives current ILE from current sensor 83, and based on the received current ILE, whether or not a leakage has occurred in the AC section of load drive device 100A during boost operation of boost converter 11 is determined. When the leakage occurs in the AC unit, the boost converter 11 is controlled so as to suppress the leakage current as described above.
[0238]
The control device 30 </ b> A performs the same functions as the control device 30.
Control device 30A includes converter control means 302D shown in FIG. 18 instead of converter control means 302. FIG. 18 is still another functional block diagram of the converter control means.
[0239]
Referring to FIG. 18, converter control means 302D is the same as converter control means 302 except that determination unit 36 of converter control unit 302 is replaced with determination unit 36D.
[0240]
The determination unit 36D receives the current ILE from the current sensor 83 and determines whether or not the received current ILE is larger than a threshold value. Then, when the current ILE is larger than the threshold value, the determination unit 36D determines that a leakage has occurred in the AC unit, generates a signal CTL, and outputs the signal CTL to the voltage command calculation unit 33. Further, the determination unit 36D determines that no leakage has occurred in the AC unit when the current ILE is equal to or less than the threshold value.
[0241]
Other than that, the determination unit 36D performs the same function as the determination unit 36.
When the switch 81 is turned on by the signal SW from the control device 30A, the leakage detector 80 detects the current ILE by the current sensor 83. Then, determination unit 36D of converter control means 302D determines that a leakage has occurred in the AC unit of load driving device 100A when current ILE from current sensor 83 is greater than the threshold value.
[0242]
Since the current ILE flowing through the capacitor 82 is smaller than the leakage current that can be detected by the leakage detector 70, the leakage detector 80 detects the leakage current that is smaller than the leakage current that can be detected by the leakage detector 70. It is an earth leakage detector.
[0243]
The reason why the switch 81 of the leakage detector 80 is periodically turned on / off is that the capacitance of the capacitor 82 is small, and therefore, if the switch 81 is always turned on, a large leakage current flows through the capacitor 82. The capacitor 82 may be damaged.
[0244]
Therefore, the switch 81 is periodically turned on / off to prevent the capacitor 82 from being damaged.
[0245]
The operation of suppressing the leakage current when leakage occurs in the load driving device 100A is performed according to the flowchart shown in any of FIGS. 7 to 9, 12, 14, and 15.
[0246]
When the operation of suppressing the leakage current when leakage occurs in load driving device 100A is performed according to the flowchart shown in any of FIGS. 8, 9, 12, 14, and 15, determination unit 36A of converter control means 302A, converter Determination unit 36B of control unit 302B and determination unit 36C of converter control unit 302C have a function of comparing current ILE with a threshold value and determining whether or not a leakage has occurred in the AC unit.
[0247]
In the overall operation of the load driving device 100A, of the overall operation of the load driving device 100, the operation of detecting the leakage in the AC unit by the leakage detector 70 is replaced with the operation of detecting the leakage by the leakage detector 80 and the determination unit 36D. The rest is the same as the overall operation of the load driving apparatus 100.
[0248]
The leak detector 80 and the determination unit 36D constitute a “leak detector”.
Others are the same as in the first embodiment.
[0249]
[Embodiment 3]
FIG. 19 is a schematic block diagram of a load driving device according to the third embodiment. Referring to FIG. 19, load drive device 100B is the same as load drive device 100 except that control device 30 of load drive device 100 is replaced with control device 30B and leakage detector 80 is added. .
[0250]
The leakage detector 80 is as described above.
In addition to the function of the control device 30, the control device 30B compares the current ILE from the current sensor 83 with a threshold value, and determines whether or not a leakage has occurred in the AC unit of the load driving device 100B. Have.
[0251]
Control device 30B includes converter control means 302E shown in FIG. 20 instead of converter control means 302. FIG. 20 is still another functional block diagram of the converter control means.
[0252]
Referring to FIG. 20, converter control means 302E is the same as converter control means 302 except that determination unit 36 of converter control unit 302 is replaced with determination unit 36E.
[0253]
The determination unit 36E receives the current ILE from the current sensor 83, determines whether or not the received current ILE is larger than a threshold value, and when the current ILE is larger than the threshold value, leakage occurs in the AC unit. It is determined that Then, the determination unit 36E generates a signal CTL and outputs it to the voltage command calculation unit 33 when it is determined that a leakage has occurred in the AC unit based on the current ILE, or when the signal DEL is received from the leakage detector 70. To do.
[0254]
Other than that, the determination unit 36E performs the same function as the determination unit 36.
The load driving device 100B includes two leakage detectors 70 and 80. Then, the leakage detector 80 detects a leakage current smaller than the leakage current that can be detected by the leakage detector 70 as described above. That is, the leakage detector 80 is more sensitive than the leakage detector 70 to detect a leakage current. Therefore, the load driving device 100B includes two leakage detectors 70 and 80 having different sensitivities.
[0255]
Thereby, in the load drive device 100B, a wide range of leakage currents can be detected.
[0256]
The operation of suppressing the leakage current when leakage occurs in the load driving device 100B is performed according to the flowchart shown in any of FIGS. 7 to 9, 12, 14, and 15.
[0257]
When the operation of suppressing the leakage current when leakage occurs in load driving device 100B is performed according to the flowchart shown in any of FIGS. 8, 9, 12, 14, and 15, determination unit 36A of converter control means 302A, converter Determination unit 36B of control unit 302B and determination unit 36C of converter control unit 302C have a function of comparing current ILE with a threshold value and determining whether or not a leakage has occurred in the AC unit.
[0258]
The overall operation of the load driving device 100B is the operation of detecting the electric leakage by the electric leakage detector 80 and the determination unit 36D and the step-down operation according to the electric leakage detection among the entire operation of the load driving device 100. The operation to be controlled is added, and the other operations are the same as the overall operation of the load driving device 100.
[0259]
The rest is the same as in the first and second embodiments.
In Embodiments 1 to 3 described above, the description has been made assuming that there is one AC motor. However, the present invention is not limited to this, and a plurality of AC motors may be provided. In this case, a plurality of inverters are connected in parallel to both ends of the capacitor 12 corresponding to the plurality of motors. In the case where leakage occurs in at least one of the plurality of motors, the voltage level of the DC voltage Vm on the inverter 20 side may be lowered by the step-down operation of the boost converter 11, and no leakage occurs. The voltage level of the DC voltage Vm on the inverter 20 side may be lowered by driving the motor in the power running mode.
[0260]
In Embodiments 1 to 3 described above, when leakage detectors 70 and 80 detect leakage, it has been described that step-up converter 11 is controlled to perform step-down operation. However, the present invention is not limited to this. What is necessary is just to control the boost converter 11 so as to stop the boosting operation when the leakage detectors 70 and 80 detect the leakage. This is because by stopping the boosting operation of the boost converter 11, it is possible to prevent the DC current Vm from increasing on the inverter 20 side and suppress the leakage current.
[0261]
The stop of the step-up operation is a concept including both maintaining the voltage level of the DC voltage Vm at the time of detecting leakage and reducing the DC voltage Vm. Control for maintaining the voltage level of DC voltage Vm is realized by setting voltage command Vdc_com of boost converter 11 to DC voltage Vm at the time of detecting leakage, switching control of NPN transistor Q1, and OFF control of NPN transistor Q2. The
[0262]
Furthermore, the inverter 20 constitutes a “DC / AC converter”.
Load driving devices 100, 100A, and 100B described in the first to third embodiments are mounted on a hybrid vehicle or an electric vehicle, and drive driving wheels of the hybrid vehicle or the electric vehicle.
[0263]
For example, when load driving devices 100, 100A, and 100B are mounted on a hybrid vehicle, AC motor M1 includes two motor generators MG1 and MG2. Motor generator MG1 is connected to the engine via a power split mechanism, starts the engine, and generates power by the rotational force of the engine. Motor generator MG2 is connected to the front wheels (drive wheels) via a power split mechanism, drives the front wheels, and generates power by the rotational force of the front wheels.
[0264]
When load driving devices 100, 100A, and 100B are mounted on an electric vehicle, AC motor M1 is connected to the front wheels (drive wheels), drives the front wheels, and generates electric power by the rotational force of the front wheels.
[0265]
Then, the load driving device 100, 100A, 100B detects the electric leakage in the AC unit while the hybrid vehicle or the electric vehicle is running and stopped, and detects the electric leakage during the boosting operation of the boost converter 11, the method described above. As a result, the DC voltage Vm on the inverter 20 side is lowered.
[0266]
Therefore, in a hybrid vehicle or an electric vehicle equipped with the load driving devices 100, 100A, 100B, the leakage current can be suppressed even if a leakage occurs.
[0267]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a load driving device according to a first embodiment.
FIG. 2 is a functional block diagram showing functions related to control of a boost converter and an inverter among the functions of the control device shown in FIG. 1;
FIG. 3 is a functional block diagram of inverter control means shown in FIG. 2;
4 is a functional block diagram of converter control means shown in FIG.
FIG. 5 is a functional block diagram of the impedance determination circuit shown in FIG. 1;
FIG. 6 is a circuit diagram showing an equivalent circuit when leakage occurs.
7 is a flowchart for explaining an operation of suppressing a leakage current when leakage occurs in the load driving device shown in FIG. 1; FIG.
FIG. 8 is another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device shown in FIG. 1;
9 is still another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device shown in FIG. 1. FIG.
FIG. 10 is another functional block diagram of the converter control means.
FIG. 11 is a diagram showing the relationship between the on-duty of the protection duty ratio and the DC voltage on the inverter side.
12 is still another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device shown in FIG. 1; FIG.
FIG. 13 is still another functional block diagram of the converter control means.
14 is still another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device shown in FIG. 1. FIG.
15 is still another flowchart for explaining the operation of suppressing the leakage current when leakage occurs in the load driving device shown in FIG. 1. FIG.
FIG. 16 is still another functional block diagram of the converter control means.
FIG. 17 is a schematic block diagram of a load driving device according to a second embodiment.
FIG. 18 is still another functional block diagram of the converter control means.
FIG. 19 is a schematic block diagram of a load driving device according to a third embodiment.
FIG. 20 is still another functional block diagram of the converter control means.
[Explanation of symbols]
10, 16 voltage sensor, 11 step-up converter, 12, 82 capacitor, 13 DC / DC converter, 14 air conditioner, 15 coupling capacitor, 17, 24, 83 current sensor, 20 inverter, 21 U-phase arm, 22 V-phase arm, 23 W-phase arm, 25, 27 Resistance component, 26 Capacitance component, 30, 30A, 30B Controller, 31 Motor control phase voltage calculation unit, 32 Inverter PWM signal conversion unit, 33, 33A Voltage command calculation unit, 34, 34A converter duty ratio calculation unit, 35 converter PWM signal conversion unit, 36, 36A, 36B, 36C, 36D, 36E determination unit, 37 calculation unit, 40 oscillation circuit, 60 impedance determination circuit, 70, 80 leakage detector, 81 switch, 100, 100A, 100B load drive Device, 301 Inverter control means, 302, 302A, 302B, 302C, 302D, 302E Converter control means, 601 to 603, 620 Noise filter, 604 to 606, 621 Band pass filter, 607 to 609, 622 Peak hold circuit, 610 612, 623 peak value extraction circuit, 613 determination circuit, N1, N2, N3 nodes, B1, B2 DC power supply, L1 reactor, Q1-Q8 NPN transistor, D1-D8 diode, SR1, SR2 system relay.

Claims (24)

A step-up operation in which the first DC voltage supplied from the power source is boosted to a second DC voltage and supplied to the load side, and the second DC voltage is stepped down to the first DC voltage and the power source side is supplied. A voltage converter that performs a step-down operation to be supplied; and
A leakage detection device for detecting leakage of the load;
A load driving device comprising: a control device that controls the voltage converter to stop the boosting operation when the leakage detection device detects a leakage of the load during the boosting operation of the voltage converter. A step-up operation in which the first DC voltage supplied from the power source is boosted to a second DC voltage and supplied to the load side, and the second DC voltage is stepped down to the first DC voltage and the power source side is supplied. A voltage converter that performs a step-down operation to be supplied; and
A leakage detection device for detecting leakage of the load;
A load driving device comprising: a control device that controls the voltage converter to perform the step-down operation when the leakage detection device detects leakage of the load during the step-up operation of the voltage converter. A DC / AC converter disposed between the voltage converter and the load;
The power source is direct current,
The load driving device according to claim 1, wherein the load is an alternating current. The voltage converter includes an upper arm and a lower arm connected in series,
4. The load according to claim 1, wherein when the leakage detection device detects a leakage of the load, the control device performs switching control on the upper arm and turns off the lower arm. 5. Drive device. The load driving device according to claim 4, wherein the control device performs switching control of the upper arm with a protection duty ratio in which a direct current flowing through the upper arm is smaller than an overcurrent of the upper arm. The control device performs switching control of the upper arm at a protection duty ratio until the second DC voltage drops to a predetermined voltage, and turns on the upper arm when the second DC voltage drops to the predetermined voltage. Control
The load driving device according to claim 5, wherein the predetermined voltage is a voltage at which a direct current flowing through the upper arm is smaller than the overcurrent. A voltage sensor for detecting the second DC voltage;
The control device holds a map indicating the relationship between the second DC voltage and the protection duty ratio, and the protection duty ratio corresponding to the second DC voltage detected by the voltage sensor is determined from the map. The load driving device according to claim 5 or 6, wherein the switching control is performed on the upper arm based on the extracted protection duty ratio. The load driving device according to claim 7, wherein the protection duty ratio includes an on-duty that is inversely proportional to the second DC voltage. The voltage converter includes an upper arm and a lower arm connected in series,
The load according to any one of claims 1 to 3, wherein when the leakage detection device detects a leakage of the load, the control device controls the upper arm to be turned on and the lower arm to be turned off. Drive device. The voltage converter includes an upper arm and a lower arm connected in series,
When the leakage detection device detects leakage of the load, the control device performs switching control on the upper arm until the second DC voltage drops to a predetermined voltage, and controls off the lower arm, When the second DC voltage drops to the predetermined voltage, the upper arm is turned off,
4. The load according to claim 1, wherein the predetermined voltage is a voltage when a voltage difference between the second DC voltage and the first DC voltage becomes a predetermined value. 5. Drive device. The leakage detection device includes:
A node connected to the ground line of the power supply via a coupling capacitor;
An oscillation circuit for oscillating an AC signal on which a plurality of frequencies are superimposed;
A determination circuit that detects the AC signal from the oscillation circuit through the node and determines whether or not a leakage has occurred in the load based on a peak value in each frequency component of the detected AC signal; The load driving device according to any one of claims 1 to 10, further comprising: The leakage detection device includes:
A capacitor connected between the load and a ground line;
A switch connected between the load and the capacitor;
A current sensor that detects a current flowing through the capacitor through the earth line;
A determination circuit that determines whether or not a leakage has occurred in the load based on a current value from the current sensor,
11. The load driving device according to claim 1, wherein the control device further periodically turns on / off the switch. 11. The leakage detection device includes:
A first leakage detector;
A second leakage detector that detects a smaller leakage than the first leakage detector;
The first leakage detector is
A node connected to the ground line of the power supply via a coupling capacitor;
An oscillation circuit for oscillating an AC signal on which a plurality of frequencies are superimposed;
A first determination for detecting the AC signal from the oscillation circuit via the node and determining whether or not a leakage has occurred in the load based on a peak value in each frequency component of the detected AC signal. A circuit,
The second leakage detector is:
A capacitor connected between the load and a ground line;
A switch connected between the load and the capacitor;
A current sensor that detects a current flowing through the capacitor through the earth line;
A second determination circuit that determines whether or not a leakage has occurred in the load based on a current value from the current sensor;
The control device further turns on and off the switch periodically, and when the first leakage detector or the second leakage detector detects the leakage of the load, the control device performs the step-down operation. The load driving device according to any one of claims 1 to 10, which controls the converter. The load drive according to any one of claims 1 to 13, wherein the voltage converter supplies the stepped-down first DC voltage to an auxiliary machine when the capacity of the power supply is a full charge amount. apparatus. The motor vehicle carrying the load drive device of any one of Claims 1-14. A computer-readable recording medium storing a program for causing a computer to execute control when leakage occurs in a load driving device,
The load driving device includes:
A step-up operation in which the first DC voltage supplied from the power source is boosted to a second DC voltage and supplied to the load side, and the second DC voltage is stepped down to the first DC voltage and the power source side is supplied. A voltage converter that performs a step-down operation to be supplied; and
Including a leakage detection device for detecting leakage of the load,
The program is
A first step of determining whether or not a leakage of the load is detected by the leakage detection device during the boosting operation of the voltage converter;
A computer-readable recording recording a program for causing the computer to execute a second step of controlling the voltage converter so as to perform the step-down operation when leakage of the load is detected; Medium. The voltage converter includes an upper arm and a lower arm connected in series,
The second step of the program is:
A first sub-step for turning off the lower arm;
The computer-readable recording medium which recorded the program for making the computer perform of Claim 16 containing the 2nd substep which carries out switching control of the said upper arm. The second sub-step includes
Determining a protection duty ratio at which a direct current flowing through the upper arm is smaller than an overcurrent of the upper arm; and
The computer-readable recording medium which recorded the program for making the computer perform of Claim 17 including step B which carries out switching control of the said upper arm by the said protection duty ratio. The second sub-step includes
19. The computer-readable recording medium recording a program for causing a computer to execute according to claim 18, further comprising a step C of turning on the upper arm when the second DC voltage drops to a predetermined voltage. Step A includes
Detecting the second DC voltage;
19. A step of extracting a protection duty ratio corresponding to the detected second DC voltage with reference to a map showing a relationship between the second DC voltage and the protection duty ratio. A computer-readable recording medium having recorded thereon a program for causing the computer to execute according to 19. The computer-readable recording medium recording a program for causing a computer to execute according to claim 20, wherein the protection duty ratio includes an on-duty that is inversely proportional to the second DC voltage. The voltage converter includes an upper arm and a lower arm connected in series,
The second step of the program is:
A first sub-step for turning off the lower arm;
The computer-readable recording medium which recorded the program for making the computer perform of Claim 16 containing the 2nd substep which carries out on control of the said upper arm. The voltage converter includes an upper arm and a lower arm connected in series,
The second step of the program is:
A first sub-step for turning off the lower arm;
17. The computer according to claim 16, further comprising: a second sub-step of performing switching control of the upper arm so that the second DC voltage drops to a predetermined voltage higher than the first DC voltage. A computer-readable recording medium on which a program for recording is recorded. The leakage detection device includes:
A first leakage detector;
A second leakage detector that detects a smaller leakage than the first leakage detector;
The first leakage detector is
A node connected to the ground line of the power supply via a coupling capacitor;
An oscillation circuit for oscillating an AC signal on which a plurality of frequencies are superimposed;
A first determination for detecting the AC signal from the oscillation circuit via the node and determining whether or not a leakage has occurred in the load based on a peak value in each frequency component of the detected AC signal. A circuit,
The second leakage detector is:
A capacitor connected between the load and a ground line;
A switch connected between the load and the capacitor;
A current sensor that detects a current flowing through the capacitor through the earth line;
A second determination circuit that determines whether or not a leakage has occurred in the load based on a current value from the current sensor;
The first step of the program is:
Periodically turning on and off the switch;
Determining whether the first leakage detector has detected a leakage of the load;
24. A program for causing a computer to execute the program according to any one of claims 16 to 23, including a step of determining whether or not the second leakage detector has detected a leakage of the load. Computer-readable recording medium.

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