JP2007325386A - DC-DC converter and DC-DC converter system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC-DC converter and DC-DC converter system, capable of independently regulating a plurality of output voltages and fetching output power as much as possible. <P>SOLUTION: A first main circuit 110 is disposed between a first voltage V1 and the primary side of a transformer TR. A second main circuit 120 is disposed the secondary side of the transformer TR and a second voltage V2. A third step-down circuit 130 is disposed between the secondary side of the transformer TR and a third voltage V3. Further, a first control circuit 140 regulates the second voltage V2 by on-off controlling a switching device provided at the first main circuit 110. A second control circuit 150 step-down regulates the third voltage V3 by on-off controlling a switching device provided at the third step-down circuit 130. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a DC-DC converter and a DC-DC converter system, and more particularly, a DC- that can generate a plurality of outputs from one voltage using a transformer and can independently adjust each output voltage (or current). The present invention relates to a DC converter and a DC-DC converter system.

  Due to social issues such as global warming and high oil prices, the use of automobiles aimed at low fuel consumption such as hybrid cars is remarkable. Generally, a hybrid vehicle is equipped with a high-voltage secondary battery (for example, 300V) used for driving an engine assist motor and a 14V secondary battery for supplying electric power to an in-vehicle electronic device. It is. In recent years, hybrid vehicles that require a 42V power source for use in electric power steering applications have been commercialized.

  In such a power supply system, the high-voltage secondary battery is charged by the engine rotating the motor to generate power (regeneration), and the generated power is converted to a voltage of 14V using a DC-DC converter. It is supplied to in-vehicle electronic devices. The voltage is also converted to 42V and supplied to an electric power steering unit or the like.

  Thus, a DC-DC converter that generates two power supplies for 14V and 42V from a high-voltage secondary battery is required.

  As a multi-output DC-DC converter, for example, the one of Patent Document 1 is known.

  However, in a power supply system mounted on a hybrid vehicle or the like, the voltage range of the high voltage secondary battery is determined by the mounted secondary battery, required system specifications, and the like, and the voltage fluctuates within the range. Moreover, the voltage of 14V power supply and 42V power supply which generate | occur | produce via a DC-DC converter from a high voltage secondary battery changes the voltage which generate | occur | produces with time according to the command from a high-order controller (for example, ECU). As described above, it is necessary to perform power conversion between the voltages that fluctuate depending on the state of the load by the DC-DC converter and to finely control the plurality of output voltages independently according to the voltage command value from the host controller.

  On the other hand, in the thing of patent document 1, a several output cannot be adjusted independently.

  On the other hand, for example, a device described in Patent Document 2 is known as a device capable of independently adjusting a plurality of outputs.

JP-A-7-135770 JP 11-215823 A

  However, the device described in Patent Document 2 has a problem that even if the output voltage can be adjusted, a large amount of output power cannot be extracted.

  An object of the present invention is to provide a DC-DC converter and a DC-DC converter system capable of independently adjusting a plurality of output voltages and extracting a large amount of output power.

(1) In order to achieve the above object, the present invention provides a DC-DC converter that connects a first voltage to a primary side of a transformer and outputs a plurality of voltages from the secondary side of the transformer. A first main circuit disposed between a first voltage and a primary side of the transformer; a second main circuit disposed between a secondary side of the transformer and a second voltage; and the transformer The second voltage is adjusted by controlling on / off of a third step-down circuit arranged between the secondary side of the first and the third voltage and the switching means provided in the first main circuit. And a second control circuit that performs step-down adjustment of the third voltage by controlling on / off of the switching means provided in the third step-down circuit.
With this configuration, a plurality of output voltages can be adjusted independently, and a large amount of output power can be extracted.

  (2) In the above (1), preferably, the switching frequency at which the second control circuit controls at least one switching means in the third step-down circuit is set so that the first control circuit has the first control circuit. This is twice the switching frequency for controlling the switching means of the main circuit.

  (3) In the above (1), preferably, the second control circuit controls the switching frequency for controlling at least one switching means in the third step-down circuit. This is the same as the switching frequency for controlling the switching means of the main circuit.

  (4) In the above (1), preferably, a third control circuit that generates the first voltage from the second voltage by controlling on / off of the switching means provided in the second main circuit. And is designed to convert power in both directions.

  (5) In the above (4), preferably, when the second control circuit converts power from the second voltage to the first voltage, at least one switching means in the third step-down circuit is provided. It is intended to be turned off.

  (6) In the above (4), preferably, when the second control circuit converts power from the second voltage to the first voltage, at least one switching means in the third step-down circuit is provided. The third voltage is adjusted by turning on and off.

  (7) In the above (1), preferably, when the voltage generation period for one cycle of the transformer voltage is T, the second control circuit performs switching in the third step-down circuit provided on the secondary side. The output voltage is adjusted by controlling the ON period of the means to T or less.

(8) In order to achieve the above object, the present invention provides a DC-DC converter that connects a first voltage to a primary side of a transformer and outputs a plurality of voltages from the secondary side of the transformer; A DC-DC converter system having a plurality of secondary batteries connected to a DC-DC converter and a host controller for instructing an output voltage of the DC-DC converter, wherein the DC-DC converter includes the first DC-DC converter. The first main circuit disposed between the voltage of the transformer and the primary side of the transformer, the second main circuit disposed between the secondary side of the transformer and the second voltage, and 2 of the transformer A first step of adjusting the second voltage by controlling on / off of a third voltage step-down circuit arranged between the secondary side and the third voltage and a switching means provided in the first main circuit; Control circuit and third step-down circuit In which the third voltage by controlling the on-off switching means and to a second control circuit for a step-down adjustment with.
With this configuration, a plurality of output voltages can be adjusted independently, and a large amount of output power can be extracted.

  According to the present invention, a plurality of output voltages can be adjusted independently, and a large amount of output power can be extracted.

Hereinafter, the configuration and operation of the DC-DC converter according to the first embodiment of the present invention will be described with reference to FIGS.
First, the basic configuration of the DC-DC converter according to the present embodiment will be described with reference to FIG.
FIG. 1 is a block diagram showing a basic configuration of a DC-DC converter according to a first embodiment of the present invention.

  The DC-DC converter 100 includes a V1-side main circuit 110 connected to the primary winding TR1 of the transformer TR, a V2-side main circuit 120 connected to the secondary winding TR2 of the transformer TR, and a secondary of the transformer TR. V3 side step-down circuit 130 connected to winding TR3, control circuits 140 and 150, and communication interface (I / F) 160 are provided.

  The V1-side main circuit 110 is connected to a DC power supply Bat1 via a first DC voltage terminal V1 +/−. The voltage V1 of the DC power supply Bat1 is, for example, 300V. The V2 side main circuit 120 is connected to the second DC voltage terminal V2 +/−. The voltage V2 is, for example, 12V. The V3 side step-down circuit 130 is connected to the third DC voltage terminal V3 +/−. The voltage V2 is 42V, for example.

  The control circuit 140 outputs control signals CS1 and CS2, controls the switching means provided in the V1 side main circuit 110 and the V2 side main circuit 120, and converts power from the V1 side to the V2 side. Note that if the switching means is not included in the V2-side main circuit 120, the control signal CS2 is not necessary. The control circuit 150 outputs the control signal CS3 and controls the switching means provided in the V3 side step-down circuit 130 to control the V3 voltage. The communication I / F 160 receives a command from the host controller 200 and outputs the command to the control circuits 140 and 150 as a voltage command value VI2 for the V2 voltage and a voltage command value VI3 for the V3 voltage, respectively.

  The detailed configurations of the V1 side main circuit 110, the V2 side main circuit 120, the V3 side step-down circuit 130, and the control circuits 140 and 150 will be described later with reference to FIG.

  Next, the operation of the DC-DC converter 100 will be described.

  In the power conversion from the DC voltage V1 to the DC voltage V2, the DC voltage V1 is converted into an AC voltage by the V1 side main circuit 110, the AC voltage is transmitted to the V2 side by the transformer TR, and the transmitted AC voltage is transmitted to the V2 side main. Rectification is performed by the circuit 120. At this time, the switching means in the V1 side main circuit 110 and the V2 side main circuit 120 are controlled using the control signals CS1 and CS2 generated by the control circuit 140. The control circuit 140 feeds back the V2 voltage signal and controls the switching means in the V1 side main circuit 110 and the V2 side main circuit 120 based on the voltage command value VI2 to adjust the V2 output voltage. Specifically, to the V2 terminal by adjusting the turn ratio of the primary winding TR1 and the secondary winding TR2 of the transformer TR and the duty (duty ratio) when a voltage is applied to the primary winding TR1. The output voltage V2 is adjusted.

  Here, Duty is defined as the ratio of the time during which voltage is generated at both ends of the winding with respect to one cycle period of the voltage generated at the winding of the transformer. A positive / negative voltage may be generated in the winding at this time, and this is calculated by the sum of the time generated by the positive voltage and the time generated by the negative voltage. That is, Duty = (t1 + t2) / T1. Here, t1 = time when the positive voltage is generated in the winding, t2 = time when the negative voltage is generated in the winding, and T1 = time of one cycle of the voltage generated in the winding.

  The adjustment of the V3 voltage is performed by the turn ratio between the primary winding TR1 and the secondary winding TR3 of the transformer TR and the V3 side step-down circuit 130. Specifically, a voltage multiplied by the turns ratio is generated at both ends of the secondary winding TR3, and the switch in the step-down circuit is turned on / off in a direction to further shorten the time (t1 + t2). As a result, the V3 side output voltage is adjusted. A specific adjustment method will be described later with reference to FIG.

  The DC-DC converter 100 of the present embodiment is applied to a hybrid vehicle or the like, the V1 voltage terminal is connected to a high voltage secondary battery of about several hundred volts, the V2 voltage terminal is a low voltage output of about 14 V, and the V3 voltage terminal is Assuming an intermediate voltage output of about 42V, it is conceivable that the voltage V1 varies greatly depending on the state of charge and deterioration of the secondary battery. In addition, command values of the voltage V2 and the voltage V3 may change during operation in response to an instruction from the host controller 200. In such a system, the duty greatly changes with time in order to adjust the V2 output voltage, but it is necessary to generate the V3 voltage and supply a necessary load current even when the duty is minimum. For this reason, it is necessary to set the turn ratio between the transformer primary winding TR1 and the secondary winding TR3 so that the V3 voltage does not drop below the command value even when the duty is minimum. By doing so, it is possible to supply necessary power from the V1 side even when the load current is large for both the voltage V2 and the voltage V3.

  The feature of this embodiment is that the V2 voltage can be adjusted by being controlled by the V1 main circuit 110 on the primary side of the transformer, and the V3 voltage is stepped down by the V3 side step-down circuit 130. The point is that it can be controlled and adjusted. With this configuration, different voltages V2 and V3 can be independently adjusted with respect to the voltage V1, and a large current can be obtained with respect to the voltages V2 and V3. The reason will be described later with reference to FIGS.

  In the above description, the voltages V2 and V3 are set by an instruction from the host controller 200. However, the adjustment voltage values V2 and V3 can be set to fixed values at the time of product shipment. Alternatively, the DC-DC converter 100 can monitor the input / output voltage by itself to change the adjustment voltage value according to the operation programmed in the DC-DC converter 100 in advance.

  In the above example, control is performed so that the output voltage matches an arbitrary set value, but control can also be performed so that the output current matches the set value. In this case, a current sensor is newly provided at the V2 or V3 terminal, and either or both of the signal from the sensor and the command values VI2 and VI3 become the output current command value, and feedback is performed so that the output current matches the set value. Control is performed.

  In the above example, it is assumed that no battery is connected to the V2 and V3 voltage terminals, but it is also possible to connect a DC power source such as a secondary battery. Although not shown, a load is connected to the V1, V2, and V3 terminals.

  In the above example, an example in which two types of secondary windings TR2 and TR3 are provided for the transformer TR. However, it is also possible to increase the number of outputs by adding additional secondary windings.

  In the above example, various output voltages can be generated by variously adjusting the turns ratio of the windings TR1, TR2, and TR3. For example, a voltage relationship of V1 ≧ V3 ≧ V2 and six voltage relationships such as V1 ≧ V2 ≧ V3, V2 ≧ V3 ≧ V1, and V3 ≧ V2 ≧ V1 can be realized.

  According to this embodiment described above, a plurality of output voltages can be adjusted independently, and a large amount of output power can be extracted.

  In addition, a multi-output DC-DC converter can be configured with fewer circuit components than a single DC-DC converter connected in parallel, and a reduction in size and cost can be realized.

Next, a specific circuit configuration and operation of the DC-DC converter according to the present embodiment will be described with reference to FIGS.
FIG. 2 is a circuit diagram showing a configuration of the DC-DC converter according to the first embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts. 3 and 4 are timing charts for explaining the operation of the DC-DC converter according to the first embodiment of the present invention.

  Next, the configuration of the V1 side main circuit 110 will be described. In the V1 side main circuit 110, a smoothing capacitor C1, switching elements SW11 and SW12 connected in series, and other switching elements SW13 and SW14 connected in series are connected to the V1 side DC power supply Bat1. Freewheel diodes D11, D12, D13, and D14 are connected in parallel to the switching elements SW11,. When MOSFETs are used as the switching elements SW11,..., SW14, MOSFETs can be used as the free wheel diodes D11, D12, D13, D14.

  In the power conversion from the V1 terminal to the V2 terminal, the switching elements SW11,..., SW14 are switched to convert a DC voltage into an AC voltage, and the AC voltage is applied to the primary winding TR1 of the transformer TR via the auxiliary reactor AL1. appear. The auxiliary reactor AL1 serves to adjust the current gradient when the polarity of the current flowing through the primary winding TR1 of the transformer TR is reversed. Here, the auxiliary reactor AL1 can be replaced by the leakage inductance of the transformer TR. In this case, the auxiliary reactor AL1 can be deleted.

  Next, the configuration of the V2 side main circuit 120 will be described. As the V2 side main circuit 120, an example using a current doubler synchronous rectifier circuit is shown. A current doubler synchronous rectifier circuit is known, for example, from Japanese Patent Laid-Open No. 2003-199339. A smoothing capacitor C2, a reactor L21 and a switching element SW22 connected in series, and a reactor L22 and a switching element SW21 connected in series are connected in parallel to the DC power source Bat2 on the V2 side. Free wheel diodes D21 and D22 are respectively connected in parallel to the switching elements SW21 and SW22. When the switching elements SW21 and SW22 are MOSFETs, a body diode can be used.

  During the power conversion operation from the V1 terminal to the V2 terminal, the V2 side main circuit 120 configured by this current doubler circuit rectifies the AC voltage generated in the secondary winding TR2 of the transformer TR by the diodes D21 and D22, Then, it is smoothed by the reactors L21 and L22 and the capacitor C2 to obtain a DC voltage V2. At this time, the switching elements SW21 and SW22 may be subjected to so-called synchronous rectification in which the diodes D21 and D22 are turned on during a period in which forward current flows from the anode to the cathode.

  Next, the configuration of the V3 side step-down circuit 130 will be described. The V3 side step-down circuit 130 rectifies the AC voltage generated in the secondary winding TR3 of the transformer TR by rectifying diodes D31 and D32. The rectified voltage is stepped down by a step-down circuit (step-down chopper) composed of switching means SW31, freewheel diode D34, and reactor L3, smoothed by capacitor C3, and output to the V3 terminal. When the switching means SW31 is a MOSFET, the body diode D33 is connected in parallel, but this circuit configuration is not a problem even if it is not present.

  In the above example, a MOSFET is used as a switching element, but a switching element such as an IGBT can also be used.

  The control circuit 140 controls the V1 side main circuit 110 and the V2 side main circuit 120 when converting power from the V1 terminal to the V2 terminal. The control circuit 140 includes an error amplifier 141, a pulse generation circuit 142, drivers 143 and 145, and an insulation circuit 144. The error amplifier 141 calculates a difference between the V2 voltage obtained from the V2 +/− terminal and the V2 voltage command value VI2 from the host controller, and sends a difference signal to the pulse generation circuit 142. The pulse generation circuit 142 receives a signal from the error amplifier 141 and generates a pulse for controlling the switching means in the main circuits 110 and 120 so as to reduce the error. The generated pulses control the V1 side main circuit 110 and the V2 side main circuit 120 as control signals CS1 and CS2 via the driver circuits 143 and 144. The insulating circuit 144 electrically insulates the driver circuit 143 for controlling the V1 side main circuit 110 and the driver circuit 144 for controlling the V2 side main circuit 120. Here, it is assumed that the error amplifier 141, the pulse generation circuit 142, etc. share the ground potential with the V2-side main circuit 120, and the insulating circuit 144 is disposed.

  The control circuit 150 controls the V3 side step-down circuit 130. The control circuit 150 includes an error amplifier 151, a pulse generation circuit 152, and a driver 153. The error amplifier 151 obtains the difference between the V3 voltage obtained from the V3 +/− terminal and the V3 voltage command value VI3 from the host controller, and sends a signal to the pulse generation circuit 152. The pulse generation circuit 152 receives a signal from the error amplifier 151 and generates a pulse for controlling the switching means in the V3 side step-down circuit 130 so as to reduce the error. The generated pulse controls the V3 side step-down circuit 130 as the control signal VI3 through the driver circuit 153.

  Although FIG. 1 shows an example in which a DC power supply is not connected to the V2 and V3 terminals, a DC power supply may be connected as in the example of FIG.

  Next, the control operation of the DC-DC converter 100 will be described with reference to FIG. In FIG. 3, A, B, C, and D correspond to the control signal CS1 of the switching elements SW11, SW12, SW13, and SW14. E and F correspond to the control signal CS2 of the switching elements SW21 and SW22. G corresponds to the control signal CS3 of the switching element SW31.

  First, the operation of the V1 side main circuit 110 will be described. As shown in FIGS. 3A and 3B, the gate signals of the switching elements SW11 and SW12 have a period of “L” at the same time so that the switching elements SW11 and SW12 are not turned on at the same time when the waveforms are switched. As shown in C and D, the gate signals of the switching elements SW13 and SW14 are provided with a period of "L" at the same time so that the switching elements SW13 and SW14 are not turned on at the same time when the waveforms are switched. However, A and C are controlled by shifting the phase.

Here, the switching element SW11 gate signal shown in A and the switching element SW14 gate signal shown in D are both on periods, and the switching element SW12 gate signal shown in B and switching element SW13 gate signals shown in C are both on periods. In addition, a voltage is generated in the primary winding TR1 of the transformer TR, and power is transmitted from the V1 terminal side to the V2 terminal side via the transformer TR. The V2 terminal voltage is adjusted by adjusting the pulse widths t1 and t2 at which the voltage is generated in the primary winding, that is, the phase difference between the control signals indicated by A and C. Further, the phase difference between the control signals indicated by A and C changes accordingly when the V1 terminal voltage or the V2 voltage command value changes.
Next, the operation of the V2 side main circuit 120 will be described. The switching elements SW21 and SW22 on the V2 terminal side perform synchronous rectification by the control signals indicated by E and F in FIG. 3 to rectify the AC voltage generated in the secondary winding TR2 of the transformer TR.

  Next, the operation of the V3 side step-down circuit 130 will be described. The V3 side step-down circuit 130 controls the switching means SW31 with the control signal G in FIG. 3 so that the transformer voltage generation periods t1 and t2 generated in the secondary winding TR3 of the transformer TR are further generated as pulse generation periods. The step-down operation is performed by controlling to be narrow like t3 and t4. Thereby, the V3 terminal voltage is adjusted.

  Here, the relationship between the periods t1, t2, t3, and t4 is t1 ≧ t3, t2 ≧ t4. By operating the V3 terminal side voltage step-down circuit 130 under such conditions, it is possible to output a large current from the V3 terminal. In other words, a large current can be obtained by using a step-down circuit to generate the V3 voltage. If the pulse widths t3 and t4 of the control signal G are wider than the voltage pulse widths t1 and t2 generated in the transformer TR, the period for effectively converting the power is eventually limited to the pulse widths t1 and t2 of the transformer voltage. For this reason, the current output during the period other than t1 and t2 is also limited, and a large current cannot be output.

  Next, the relationship between the transformer voltage and the control signal G will be described with reference to FIG. FIG. 4A shows a case where the V2 voltage command value is set to the maximum voltage in the adjustment range. Although the V1 input voltage and the V2 set voltage change during operation, in this case, the generation period of the voltage generated in the transformer to maximize the V2 output voltage is also maximum (t1max + t2max).

  At this time, the control signal G is controlled so as to always operate in the range of t1max ≧ t3max although the pulse width may change from t3min to t3max according to the command value of the V3 voltage. This is because even if the control signal G is generated under the condition of t1max <t3max, a large output current cannot be obtained from the V3 terminal, as described with reference to FIG. Similarly, the operation is performed in the range of t2max ≧ t4max.

  FIG. 4B shows a case where the V2 voltage command value is set to the minimum voltage in the adjustment range. The V1 input voltage and the V2 set voltage change during operation. In this case, the generation period of the voltage generated in the transformer to minimize the V2 output voltage is also the minimum (t1min + t2min).

  At this time, the control signal G is controlled so that it always operates in the range of t1min ≧ t3max, although the pulse width may change from t3min to t3max according to the command value of the V3 voltage. This is for the same reason as in the case of FIG. Similarly, the operation is performed in the range of t2min ≧ t4max.

  Thus, in the case of FIG. 4A, the operation is performed under the conditions of t1max ≧ t3max and t2max ≧ t4max, and in the case of FIG. 4B, the operation is performed under the conditions of t1min ≧ t3max and t2min ≧ t4max. Thus, it is necessary to set in advance the turns ratio of the windings TR1, TR2, TR3 of the transformer TR in consideration of the V1 input voltage range, the V2, V3 set voltage range. For example, when V1 = 300V, V2 = 14V, and V3 = 42V, if the maximum duty of the gate signal of the switching element of the V1 side main circuit 110 is 20% (t1max = 0.2T), the V1 side main circuit 110 The output is 60V. That is, a voltage of 60 V is applied to the primary winding of the transformer TR. When the turns ratio of the windings TR1, TR2 and TR3 of the transformer TR is 5: 1: 4, 12V is output to the secondary winding TR2 and rectified by the V2 side main circuit 120 to obtain a V2 voltage of 12V. Obtainable. Further, 48V is output to the secondary winding TR3, and this is stepped down to 42V by the V3 side step-down circuit 130, whereby a V3 voltage of 42V can be obtained.

  As described above, according to the present embodiment, among the plurality of output voltages, the V2 voltage can be adjusted by the control circuit 140 by the V1 side main circuit 110, and the V3 voltage is reduced by the control circuit 150 by the V3 side step-down. Adjustment is possible with the circuit 130. Furthermore, since the V3 voltage is obtained by the step-down circuit 130, the output power can be increased.

Next, the configuration and operation of the DC-DC converter according to the second embodiment of the present invention will be described with reference to FIGS.
First, the basic configuration of the DC-DC converter according to the present embodiment will be described with reference to FIG.
FIG. 5 is a block diagram showing a basic configuration of a DC-DC converter according to the second embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts.

  The embodiment shown in FIGS. 1 to 4 obtains the low V2 and V3 voltages from the high V1 voltage, whereas in the present embodiment, the low V1 voltage is obtained from the high V1 voltage. This is a bidirectional DC-DC converter that obtains the V2 and V3 voltages and obtains the high V1 voltage from the low V2 voltage.

  Whether or not to supply power to the V3 terminal at the time of power conversion from the V2 voltage to the V1 voltage can be selected depending on whether or not the V3 side step-down circuit 130 is operated. The V1 side main circuit 110 and the V2 side main circuit 120 have a circuit configuration capable of bidirectional operation.

  In the present embodiment, the DC-DC converter 100A includes a control circuit 170 and selectors SL1 and SL2 in addition to the configuration shown in FIG.

  The control circuit 170 controls the V2 side main circuit 120 and the V1 side main circuit 110, and converts power from the V2 voltage at the V2 terminal to the V1 voltage at the V1 terminal. The selector SL1 selects one of the signals CS1 and CS4 from the control circuit 170 and the control circuit 140 and supplies the selected signal to the V1 side main circuit 110 as the control signal CS-B. The selector SL2 selects one of the signals CS2 and CS5 from the control circuit 170 and the control circuit 140, and supplies the selected signal to the V2-side main circuit 120 as the control signal CS-A.

  The communication I / F 160 outputs a selector switching signal C-SL for switching the inputs of the selectors SL1 and SL2 and a voltage command value VI1 for the V1 voltage from the host controller 200 in response to an instruction from the host controller 200.

  Next, the operation of the DC-DC converter 100A of this embodiment will be described. In the power conversion from the V1 terminal to the V2 terminal, the control signals CS1 and CS2 from the control circuit 140 are selected by the selectors SL1 and SL2, and the signals CS-A and CS-B are used as the V1 side main circuit 110 and the V2 side main circuit. 120 is performed. At this time, the V1 side main circuit 110 converts the DC voltage Bat1 into an AC voltage by switching the built-in switching means, and generates an AC voltage at both ends of the winding TR1. The alternating voltage generated in the winding TR1 is multiplied by the transformer turns ratio (TR2 / TR1) and is also generated at both ends of the winding TR2. The AC voltage generated in the winding TR2 is rectified by the V2 side main circuit 120 and output to the V2 terminal. At this time, the control circuit 140 detects the V2 voltage from the V2 +/− terminal and generates control signals CS1 and CS2 so as to coincide with the command value VI2.

  On the other hand, in the power conversion from the V2 terminal to the V1 terminal, the control signals CS4 and CS5 from the control circuit 170 are selected by the selectors SL1 and SL2, and the signals CS-A and CS-B are used as the V1 side main circuit 110 and the V2 side. It is supplied to the main circuit 120 and performed. At this time, the V2-side main circuit 120 switches the built-in switching means to convert the DC voltage Bat2 into an AC voltage, and generates an AC voltage at both ends of the winding TR2. The AC voltage generated in the winding TR2 is multiplied by the transformer turns ratio (TR1 / TR2) and is also generated at both ends of the winding TR1. The AC voltage generated in the winding TR1 is rectified by the V1 side main circuit 110 and output to the V1 terminal. At this time, the control circuit 170 detects the V1 voltage from the V1 +/− terminal and generates control signals CS4 and CS5 so as to coincide with the command value VI1.

  Here, at the time of power conversion from the V1 terminal to the V2 terminal or at the time of power conversion from the V2 terminal to the V1 terminal, the control circuit 150 and the V3 side step-down circuit 130 are operated in the same manner as in the embodiment of FIG. Thus, power can be output from the V3 terminal. Further, if power supply from the V3 terminal is unnecessary, the V3 side step-down circuit 130 is not operated.

  In the above example, power can be converted from the V1 terminal to the V2 terminal, and the V2 voltage can be adjusted to a command value from the host controller. Also, power conversion from the V2 terminal to the V1 terminal is possible, and in that case, the V1 voltage can be adjusted to a command value from the host controller. In these cases, by operating the V3 side step-down circuit 130, power can be supplied to the V3 terminal to adjust the voltage. When power supply to the V3 terminal is unnecessary, it can be realized by not operating the V3 side step-down circuit 130. That is, when power is supplied from the V2 terminal, power can be output not only from the V1 terminal but also from the V3 terminal if necessary.

  In the above example, the output voltage is controlled to match a certain reference voltage value. However, the output current can also be controlled to match a certain reference current value. In this case, a current sensor that detects current flowing in the V1, V2, and V3 voltage terminals is newly provided, and any one or more of the signals from the sensors and the command values VI1, VI2, and VI3 become output current command values. Feedback control is performed so that the output current matches the command value. In this embodiment, the V1, V2, and V3 voltages are adjusted according to the command value from the host controller. However, feedback control can be performed to a fixed voltage value set in advance in the DC-DC converter 100A. It is.

Next, a specific circuit configuration and operation of the DC-DC converter according to the present embodiment will be described with reference to FIGS. 6 and 7.
FIG. 6 is a circuit diagram showing a configuration of a DC-DC converter according to the second embodiment of the present invention. 2 and 5 indicate the same parts. FIG. 7 is a timing chart for explaining the operation of the DC-DC converter according to the second embodiment of the present invention.

  6 mainly illustrates the case of converting the V2 voltage to the V1 voltage, the illustration of the control circuit 140 and the selectors SL1 and SL2 illustrated in FIG. 5 is omitted. The conversion from the V1 voltage to the V2 and V3 voltages is the same as that described with reference to FIG.

  The configurations of the V1-side main circuit 110, the V2-side main circuit 120, and the V3-side step-down circuit 130 are the same as those in FIG. The difference from FIG. 2 is that the control circuit 170 controls the V1 side main circuit 110 and the V2 side main circuit 120. The control circuit 170 detects the V1 terminal voltage from the V1 +/− terminal, and operates the main circuits 120 and 110 so as to coincide with the target voltage.

  In the power conversion from the V2 terminal to the V1 terminal, the switching elements SW21 and SW22 in the V2 side main circuit 120 are alternately turned on to convert the DC voltage at the V2 terminal into an AC voltage, and to the winding TR2 of the transformer TR. Generate AC voltage. The generated AC voltage is multiplied by the turns ratio (TR1 / TR2) of the transformer TR, and a voltage is generated at both ends of the winding TR1. The generated voltage is rectified to a DC voltage by the V1 side main circuit 110 to generate a V1 terminal voltage. The V1 terminal voltage can be adjusted by controlling the on / off periods of the switching elements SW21 and SW22 in the V2 side main circuit 120.

  The V1 side main circuit 110 rectifies the AC voltage generated in the winding TR1 of the transformer TR by the diodes D11, D12, D13, and D14 and converts it into a DC voltage. At this time, the switching elements SW11, SW12, SW13, and SW14 can be so-called synchronous rectification in which the diodes D11, D12, D13, and D14 are turned on during a period in which forward current flows from the anode to the cathode.

  During power conversion from the V2 terminal to the V1 terminal, a voltage is also generated in the winding TR3 sharing the transformer. Here, if the switching means SW31 incorporated in the V3 side step-down circuit 130 is switched, power can also be output from the V3 terminal. When the switching means SW31 is kept off, power cannot be output from the V3 terminal. In this manner, whether or not power is output from the V3 terminal can be controlled by operating the V3 side step-down circuit 130 or not. Whether or not to output power to the V3 terminal is determined by the system and application in which the present DC-DC converter is mounted.

  The control circuit 170 controls the V1 side main circuit 110 and the V2 side main circuit 120 when converting power from the V2 terminal to the V1 terminal. The control circuit 170 includes an insulation circuit 171, an error amplifier 172, a pulse generation circuit 173, and drivers 174 and 175. The insulating circuit 171 transmits the V1 +/− terminal voltage to the error amplifier 172 while electrically insulating. The error amplifier 172 calculates the difference between the V1 terminal voltage obtained via the insulation circuit 171 and the V1 voltage command value VI1 from the host controller, and sends a signal to the pulse generation circuit 173. The pulse generation circuit 173 receives a signal from the error amplifier 172 and generates a pulse for controlling the switching means in the V1 side main circuit 110 and the V2 side main circuit 120 so as to reduce the error. The generated pulses control the V1 side main circuit 110 and the V2 side main circuit 120 as control signals CS4 and CS5 via the driver circuits 174 and 175. At this time, the error amplifier 172, the pulse generation circuit 173, etc. are provided with the insulating circuit 171 on the assumption that they share the ground potential with the V2-side main circuit 120.

  Next, the control operation of the DC-DC converter 100A will be described with reference to FIG. In FIG. 7, A, B, C, and D correspond to the control signal CS4 of the switching elements SW11, SW12, SW13, and SW14. E and F correspond to the control signal CS5 of the switching elements SW21 and SW22. G corresponds to the control signal CS3 of the switching element SW31.

  In this example, the control signals A to D are turned off, and the AC voltage generated in the winding TR1 of the transformer TR is rectified by the diodes D11, D12, D13, and D14. On the other hand, the control signals E and F for controlling the V2-side switching elements SW21 and SW22 are alternately switched to generate an alternating voltage on the winding TR2 of the transformer TR. Specifically, a voltage is generated in the transformer winding TR2 during the period when the control signal E or F is “L”, and power is sent to the V1 side. At this time, in order to extract power from the V3 terminal, the control signal G is operated as shown in FIG.

  The relationship between the transformer voltage and the control signal G is controlled so that t11 ≧ t13 and t12 ≧ t14 for the same reason as shown in FIG.

  In the above description, the power conversion operation from the V2 terminal to the V1 terminal has been described. However, as shown in FIG. 2, the power conversion operation from the V1 terminal to the V2 terminal can be combined with the V1 and V2 terminals. Can be converted in both directions. At this time, it is also possible to select whether or not power conversion to the V3 terminal is possible. The V1 side main circuit 110 and the V2 side main circuit 120 shown in FIG. 2 and FIG. 5 have a circuit configuration capable of bidirectional power conversion, so that bidirectional operation is possible.

  In this example, an example in which a MOSFET is used as a switching element has been described, but a switching element such as an IGBT can also be used.

  As described above, according to the present embodiment, among the plurality of output voltages, the V2 voltage can be adjusted by the control circuit 140 by the V1 side main circuit 110, and the V3 voltage is reduced by the control circuit 150 by the V3 side step-down. Adjustment is possible with the circuit 130. Furthermore, since the V3 voltage is obtained by the step-down circuit 130, the output power can be increased. In addition, since the low-voltage V2 voltage can be converted into the high-voltage V1 voltage, a bidirectional DC-DC converter can be obtained.

Next, the configuration and operation of the DC-DC converter according to the third embodiment of the present invention will be described with reference to FIG.
FIG. 8 is a block diagram showing a configuration of a DC-DC converter according to the third embodiment of the present invention. The same reference numerals as those in FIG. 2 indicate the same parts.

  The basic configuration of the DC-DC converter 100B is the same as that shown in FIG. 2, but the transformer TR 'is a type that does not have the secondary winding TR3 shown in FIG. When the V1 voltage is 300 V, the V2 voltage is 42 V and the V3 voltage is 14 V, so the turns ratio of the windings TR1 and TR2 'of the transformer TR is 5: 4. When 60V is input to the primary winding TR1 of the transformer, 48V is obtained in the secondary winding TR2 'of the transformer. Further, the V3 side step-down circuit 130B rectifies and steps down 42V to obtain a V3 voltage of 14V. Therefore, the configuration of the V3 side step-down circuit 130B is partially different from the configuration of the V3 side step-down circuit 130 in FIG. Yes. Other configurations are the same as those in FIG.

  2, the rectifier diodes D31 and D32 are connected to the secondary winding TR2 ′ of the transformer TR, and both ends of the secondary winding TR2 of the transformer TR are connected by the diodes D31 and D32. Is rectified and supplied to the switching means SW31. By controlling the duty of the gate signal of the switching means SW31, the voltage can be lowered from 42V to 14V.

  Similar to FIG. 6, a bidirectional DC-DC converter can be configured by including the control circuit 170 and the selectors SL <b> 1 and SL <b> 2.

  As described above, according to the present embodiment, among the plurality of output voltages, the V2 voltage can be adjusted by the control circuit 140 by the V1 side main circuit 110, and the V3 voltage is reduced by the control circuit 150 by the V3 side step-down. Adjustment is possible with the circuit 130. Furthermore, since the V3 voltage is obtained by the step-down circuit 130, the output power can be increased. In addition, since the low-voltage V2 voltage can be converted into the high-voltage V1 voltage, a bidirectional DC-DC converter can be obtained.

  Furthermore, one secondary winding can be shared and a plurality of output voltages can be obtained. With such a configuration, the secondary winding can be reduced and the size of the transformer can be reduced.

Next, the configuration and operation of the DC-DC converter according to the fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 9 is a block diagram showing a configuration of a DC-DC converter according to the fourth embodiment of the present invention. The same reference numerals as those in FIG. 2 indicate the same parts. FIG. 10 is a timing chart for explaining the operation of the DC-DC converter according to the fourth embodiment of the present invention.

  The basic configuration of the DC-DC converter 100C is the same as that shown in FIG. 2, but the V3 side step-down circuit 130C is further connected to the switching means SW31 in parallel with the V3 side step-down circuit 130 shown in FIG. SW32 is provided, and freewheel diode D35 is provided in parallel with switching means SW32.

  In this example, the AC voltage generated in the secondary winding TR3 of the transformer TR is rectified by the rectifying diodes D31 and D32. The rectified voltage is stepped down by a step-down circuit (step-down chopper) composed of switching means SW31, SW32, a free wheel diode D34, and a reactor L3 connected in parallel, smoothed by a smoothing capacitor C3, and output to the V3 terminal. The switching means SW31 and SW32 are controlled by gate signals G1 and G2 from the control circuit 150C. When the switching means SW31 and SW32 are MOSFETs, the body diodes D33 and D35 are connected in parallel. However, in this circuit configuration, the diodes D33 and D35 may be omitted.

  Next, as shown in FIG. 10, the V3 side step-down circuit 130C controls the pulse width (t1, t2) of the voltage generated in the transformer TR to be further narrowed. For this reason, the switching means SW31 and SW32 are controlled by the control signals G1 and G2 to perform the step-down operation, thereby outputting the V3 voltage. At this time, the relationship between the pulse widths t1, t2, t3, and t4 is controlled so that t1 ≧ t3 and t2 ≧ t4. By operating the V3 side step-down circuit 130C under such conditions, it is possible to perform a step-down operation and to output a large current from the V3 terminal.

  Here, the frequencies of the gate signals G1 and G2 for controlling the switching means SW31 and SW32 are the same as the transformer voltage. This is because the switching means SW31 and SW32 are connected in parallel. As shown in FIG. 2, when controlling by one switching means SW31, as shown in FIG. 3, it is necessary to switch at twice the frequency of the transformer voltage. Therefore, it is easy to cope with the higher frequency of the DC-DC converter.

  Furthermore, the switching frequency of the switching means can be set to ½ of the transformer voltage by using four parallel switching means instead of two parallel means.

  Similar to FIG. 6, a bidirectional DC-DC converter can be configured by including the control circuit 170 and the selectors SL <b> 1 and SL <b> 2.

  As described above, according to the present embodiment, among the plurality of output voltages, the V2 voltage can be adjusted by the control circuit 140 by the V1 side main circuit 110, and the V3 voltage is reduced by the control circuit 150 by the V3 side step-down. Adjustment is possible with the circuit 130. Furthermore, since the V3 voltage is obtained by the step-down circuit 130, the output power can be increased. In addition, since the low-voltage V2 voltage can be converted into the high-voltage V1 voltage, a bidirectional DC-DC converter can be obtained.

  Further, the control signal for controlling the V3 side step-down circuit can be lowered in frequency, and can easily cope with the higher frequency of the DC-DC converter.

Next, the configuration and operation of the DC-DC converter according to the fifth embodiment of the present invention will be described with reference to FIG.
FIG. 11 is a block diagram showing a configuration of a DC-DC converter according to the fifth embodiment of the present invention. The same reference numerals as those in FIG. 2 indicate the same parts.

  The basic configuration of the DC-DC converter 100D is the same as that of FIG. 2, but the V3 side step-down circuit 130D is configured to be capable of bidirectional operation. That is, except when the V3 terminal is an output terminal, the V3 terminal can be used as an input and output from the V1 terminal or V2 terminal.

  Therefore, the V3 side step-down circuit 130D includes switching means SW33, SW34, and SW35 in addition to the switching means SW31. In addition, diodes D34, D35, D36 are provided in parallel with the switching means SW33, SW34, SW35, respectively. By controlling the switching means SW33, SW34, SW35, a step-down operation from the secondary winding TR3 to the V3 terminal and a step-up operation from the V3 terminal to the secondary winding TR3 are performed.

  In the present circuit, when the step-down operation is performed from the secondary winding TR3 to the V3 terminal, the control circuit 150D turns off the control signals G3, G4, G5, and turns off the switching means SW33, SW34, SW35, and the diode Only D34, D35, and D36 are operated. In this way, by controlling the control signals G3, G4, G5, the step-down operation becomes the same operation as the V3-side main circuit 130 shown in FIG. The control signal G1 at this time also has the same signal waveform as the control signal G in FIG.

  When the step-up operation of the V3 side step-down circuit 130D is performed, the high voltage generated by operating the step-up chopper constituted by the reactor L3 and the switching unit SW35 (that is, the control circuit 150D performs the switching operation of the control signal G5) is the switching unit. SW33 and SW34 are alternately turned on / off to generate an AC voltage in the secondary winding TR3 of the transformer TR. At this time, the switching means SW31 is always turned on. By operating in this way, an AC voltage can be generated in the secondary winding TR3 of the transformer TR using the V3 terminal as an input voltage. The generated AC voltage can be rectified by the V1 side main circuit 110 and the V2 side main circuit 120 to output power from the V1 terminal and the V2 terminal.

  Similar to FIG. 6, a bidirectional DC-DC converter can be configured by including the control circuit 170 and the selectors SL <b> 1 and SL <b> 2.

  As described above, according to the present embodiment, among the plurality of output voltages, the V2 voltage can be adjusted by the control circuit 140 by the V1 side main circuit 110, and the V3 voltage is reduced by the control circuit 150D by the V3 side step-down. Adjustment is possible with the circuit 130D. Furthermore, since the V3 voltage is obtained by the step-down circuit 130D, the output power can be increased. In addition, since the low-voltage V2 voltage can be converted into the high-voltage V1 voltage, a bidirectional DC-DC converter can be obtained.

  Further, power can be output from the V1 terminal or the V2 terminal with the V3 terminal as an input.

Next, the configuration and operation of the DC-DC converter according to the sixth embodiment of the present invention will be described with reference to FIG.
FIG. 12 is a block diagram showing a configuration of a DC-DC converter according to the sixth embodiment of the present invention. The same reference numerals as those in FIG. 2 indicate the same parts.

  The basic configuration of the DC-DC converter 100E is the same as in FIG. 2, but the V3-side step-down circuit 130E is configured to be capable of bidirectional operation, as in FIG. That is, except when the V3 terminal is an output terminal, the V3 terminal can be used as an input and output from the V1 terminal or V2 terminal.

  Therefore, the V3 side step-down circuit 130E includes a reactor L31 and switching means SW36, SW37, SW38, SW39. Further, diodes D37, D38, D39, D39A are provided in parallel with the switching means SW36, SW37, SW38, SW39, respectively. By controlling the switching means SW36, SW37, SW38, SW39, a step-down operation from the secondary winding TR3 to the V3 terminal and a step-up operation from the V3 terminal to the secondary winding TR3 are performed.

  In this circuit, when the step-down operation is performed from the secondary winding TR3 to the V3 terminal, the control circuit 150D turns off the control signals G6, G7, G8, and G9 and turns off the switching means SW36, SW37, SW38, and SW39. Only the diodes D37, D38, D39, and D39A are operated. In this way, by controlling the control signals G6, G7, G8, and G9, the step-down operation becomes the same operation as that of the V3-side main circuit 130 shown in FIG.

  When the V3 side step-down circuit 130E is boosted, it is generated by operating the step-up chopper constituted by the reactors L3 and L31 and the switching means SW37 and SW36 (that is, the control circuit 150E switches the control signals G8 and G9). The switching means SW36 and SW37 are alternately turned on / off to control the high voltage, and an alternating voltage is generated in the secondary winding TR3 of the transformer TR. At this time, the switching means SW38 and SW39 are always turned on. By operating in this way, an AC voltage can be generated in the secondary winding TR3 of the transformer TR using the V3 terminal as an input voltage. The generated AC voltage can be rectified by the V1 side main circuit 110 and the V2 side main circuit 120 to output power from the V1 terminal and the V2 terminal.

  Similar to FIG. 6, a bidirectional DC-DC converter can be configured by including the control circuit 170 and the selectors SL <b> 1 and SL <b> 2.

  As described above, according to this embodiment, among the plurality of output voltages, the V2 voltage can be adjusted by the V1 side main circuit 110 by the control circuit 140, and the V3 voltage is stepped down by the control circuit 150E. Adjustment is possible with the circuit 130. Further, since the voltage V3 is obtained by the step-down circuit 130E, the output power can be increased. In addition, since the low-voltage V2 voltage can be converted into the high-voltage V1 voltage, a bidirectional DC-DC converter can be obtained.

  Further, power can be output from the V1 terminal or the V2 terminal with the V3 terminal as an input.

Next, the configuration and operation of the DC-DC converter according to the seventh embodiment of the present invention will be described with reference to FIG.
FIG. 13 is a block diagram showing a configuration of a DC-DC converter according to a seventh embodiment of the present invention. The same reference numerals as those in FIG. 2 indicate the same parts.

  The basic configuration of the DC-DC converter 100F is the same as that shown in FIG.

  In this example, the V2-side main circuit 120F is a center tap type diode rectification, and includes diodes D24 and D25, a freewheel diode D23, and a reactor L23. The AC voltage generated in the secondary winding TR2 is rectified by the diodes D24 and D25.

  As described above, according to the present embodiment, the V3 voltage among the plurality of output voltages can be adjusted by the V3 side step-down circuit 130 by the control circuit 150. Furthermore, since the V3 voltage is obtained by the step-down circuit 130, the output power can be increased.

  Further, although the V2 terminal is exclusively used for output, since the switching means is not used, control is unnecessary and the number of parts is reduced, so that the V2 side main circuit 120 can be reduced in size.

Next, the configuration and operation of the DC-DC converter according to the eighth embodiment of the present invention will be described with reference to FIG.
FIG. 14 is a block diagram showing a configuration of a DC-DC converter according to the eighth embodiment of the present invention. The same reference numerals as those in FIG. 2 indicate the same parts.

  The basic configuration of the DC-DC converter 100G is the same as that in FIG. 2, but the V2-side main circuit 120G is a center tap system capable of bidirectional operation. The V2-side main circuit 120G includes switching means SW23 and SW24, diodes D26 and D27, and a reactor L23. The AC voltage generated in the secondary winding TR2 is rectified by the diodes D26 and D27, smoothed by the reactor L23 and the capacitor C2, and a V2 output voltage is obtained. It is also possible to perform so-called synchronous rectification in which the switching means SW23 and SW24 are turned on during the period in which the diodes D26 and D27 pass current in the forward direction. When the V2 terminal is used as an input, by alternately turning on the switching means SW23 and SW24, an alternating voltage is generated in the secondary winding TR2, and an output voltage can be obtained from the V1 terminal or the V3 terminal. Although not shown, a bidirectional DC-DC converter is configured by including the control circuit 170 and the selectors SL1 and SL2 as in FIG.

  As described above, according to the present embodiment, among the plurality of output voltages, the V2 voltage can be adjusted by the control circuit 140 by the V1 side main circuit 110, and the V3 voltage is reduced by the control circuit 150 by the V3 side step-down. Adjustment is possible with the circuit 130. Furthermore, since the V3 voltage is obtained by the step-down circuit 130, the output power can be increased. In addition, since the low-voltage V2 voltage can be converted into the high-voltage V1 voltage, a bidirectional DC-DC converter can be obtained.

Next, the configuration of the in-vehicle hybrid system equipped with the DC-DC converter according to each embodiment of the present invention will be described with reference to FIG.
FIG. 15 is a system block diagram showing a configuration of an in-vehicle hybrid system equipped with a DC-DC converter according to each embodiment of the present invention. 1 and 2 indicate the same parts.

  Engine 210 and motor / generator 215 are mechanically coupled. The motor / generator 215 is driven by the engine 210 during regeneration and operates as a generator, and operates as a motor during power running.

  The inverter / converter 220 rotates the motor by the power of the high-voltage DC power supply Bat1 as an inverter during power running, and converts the AC voltage generated by the generator as a converter to DC during regeneration to charge the high-voltage DC power supply Bat1. To do.

  The DC-DC converter 100 is disposed between the power sources Bat1, Bat2, and Bat3, and performs power conversion. The first electronic device 230 is an in-vehicle electronic device that operates with a DC power source Bat1, and the second electronic device 235 is an in-vehicle electronic device that operates with a DC power source Bat3. The battery controllers 240, 245, and 250 perform power management of the DC power supplies Bat1, Bat2, and Bat3, respectively. The engine control unit (ECU) 200 controls the engine 210 and the motor / generator 215, and functions as a host system for controlling the DC-DC converter 100. The engine control unit (ECU) 200 controls the direction of power conversion between the DC power supplies Bat1, Bat2, Bat3. Switching and setting information such as a target command voltage is sent to the DC-DC converter 100, and information such as an operating state is received from the DC-DC converter 100. The battery controllers 240, 245 and 250 and the ECU 200 communicate via the network NW and exchange information with each other.

  In this example, it is assumed that the DC-DC converter 100 communicates with the ECU 200 individually. For example, the DC-DC converter 100 is also directly connected to the network 110 to communicate with the ECU 200 and the battery controllers 240, 245, 250. It may be made to perform.

  The DC-DC converter 100 has a function of supplying electric power from the DC power supply Bat1 to the in-vehicle electronic devices connected to the DC power supply Bat2 and the DC power supply Bat3, and is used as an emergency for starting the engine when the DC power supply Bat1 deteriorates. It has a function of supplying power from the power source Bat2 to the DC power source Bat1.

  The present invention is suitable for supplying a 14V output for driving on-vehicle electrical components or a 42V output used for electric power steering from a high voltage secondary battery mounted on a hybrid vehicle or the like. In addition, the present invention is not limited to in-vehicle use, and can be widely applied to a system that requires three or more types of voltages and performs power conversion between those voltages. Furthermore, it is applicable not only to these uses but also to power conversion between different DC voltages.

  Note that the various DC power sources can be configured with capacitors in addition to the secondary battery.

As described above, according to the present embodiment, a multi-output DC-DC converter can be realized with a small circuit scale in an in-vehicle system.

It is a block diagram which shows the basic composition of the DC-DC converter by the 1st Embodiment of this invention. 1 is a circuit diagram showing a configuration of a DC-DC converter according to a first embodiment of the present invention. It is a timing chart explaining operation | movement of the DC-DC converter by the 1st Embodiment of this invention. It is a timing chart explaining operation | movement of the DC-DC converter by the 1st Embodiment of this invention. It is a block diagram which shows the basic composition of the DC-DC converter by the 2nd Embodiment of this invention. It is a circuit diagram which shows the structure of the DC-DC converter by the 2nd Embodiment of this invention. It is a timing chart explaining operation | movement of the DC-DC converter by the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the DC-DC converter by the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the DC-DC converter by the 4th Embodiment of this invention. It is a timing chart explaining operation | movement of the DC-DC converter by the 4th Embodiment of this invention. It is a block diagram which shows the structure of the DC-DC converter by the 5th Embodiment of this invention. It is a block diagram which shows the structure of the DC-DC converter by the 6th Embodiment of this invention. It is a block diagram which shows the structure of the DC-DC converter by the 7th Embodiment of this invention. It is a block diagram which shows the structure of the DC-DC converter by the 8th Embodiment of this invention. It is a system block diagram which shows the structure of the vehicle-mounted hybrid system carrying the DC-DC converter by each embodiment of this invention.

Explanation of symbols

100 ... DC-DC converter 110 ... V1 side main circuit 120 ... V3 side step-down circuit 130 ... V2 side main circuit 140,150 ... control circuit 160 ... communication interface 200 ... high-order controller TR ... transformer

Claims (8)

A DC-DC converter that connects a first voltage to a primary side of a transformer and outputs a plurality of voltages from a secondary side of the transformer,
A first main circuit disposed between the first voltage and a primary side of the transformer;
A second main circuit disposed between the secondary side of the transformer and a second voltage;
A third step-down circuit disposed between the secondary side of the transformer and a third voltage;
A first control circuit for adjusting the second voltage by controlling on / off of the switching means provided in the first main circuit;
A DC-DC converter comprising a second control circuit for stepping down the third voltage by controlling on / off of switching means provided in the third step-down circuit. The DC-DC converter according to claim 1, wherein
The switching frequency at which the second control circuit controls at least one switching means in the third step-down circuit is 2 of the switching frequency at which the first control circuit controls the switching means of the first main circuit. A DC-DC converter characterized by being doubled. The DC-DC converter according to claim 1, wherein
The switching frequency at which the second control circuit controls at least one switching means in the third step-down circuit is the same as the switching frequency at which the first control circuit controls the switching means of the first main circuit. A DC-DC converter characterized by the above. The DC-DC converter according to claim 1, wherein
A third control circuit that generates the first voltage from the second voltage by controlling on / off of the switching means included in the second main circuit, and bi-directionally converts the power. DC-DC converter. The DC-DC converter according to claim 4, wherein
The DC-DC converter characterized in that the second control circuit turns off at least one switching means in the third step-down circuit when converting power from the second voltage to the first voltage. The DC-DC converter according to claim 4, wherein
When the second control circuit performs power conversion from the second voltage to the first voltage, the second control circuit turns on / off at least one switching means in the third step-down circuit to change the third voltage. A DC-DC converter characterized by adjusting. The DC-DC converter according to claim 1, wherein
When the voltage generation period for one cycle of the transformer voltage is T, the second control circuit controls the ON period of the switching means in the third step-down circuit provided on the secondary side to be T or less and outputs it. A DC-DC converter characterized by adjusting a voltage. A DC-DC converter that connects a first voltage to the primary side of the transformer and outputs a plurality of voltages from the secondary side of the transformer, a plurality of secondary batteries connected to the DC-DC converter, and the DC A DC-DC converter system having a host controller for indicating the output voltage of the DC converter,
The DC-DC converter
A first main circuit disposed between the first voltage and a primary side of the transformer;
A second main circuit disposed between the secondary side of the transformer and a second voltage;
A third step-down circuit disposed between the secondary side of the transformer and a third voltage;
A first control circuit for adjusting the second voltage by controlling on / off of the switching means provided in the first main circuit;
A DC-DC converter system comprising a second control circuit for stepping down the third voltage by controlling on / off of a switching means provided in the third step-down circuit.

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