JP5969240B2 - Short-circuit detection method for switching switching element of winding switching device provided for three-phase AC motor and opening of switching switching element of winding switching device provided for three-phase AC motor Failure detection method - Google Patents

Description

  The present invention relates to a winding switching device provided in a three-phase AC motor, a method of detecting a short circuit failure in a switching element of the winding switching device provided in the three-phase AC motor, and switching of the winding switching device provided in the three-phase AC motor. The present invention relates to a switching element open failure detection method.

  Conventionally, in vehicle-mounted accessory motors driven by AC variable frequency power supplies and motors used as machine tool spindles and vehicle drive devices, a sufficiently large torque can be obtained in the low-speed region and operation in the high-speed region can be performed. As a means for making it possible, a winding switching method is employed (for example, Patent Document 1).

  In Patent Document 1, each phase winding of a motor whose one end is connected to an inverter is divided, and its middle end or termination is switched by switching means composed of an IGBT and a number of diodes, and is sufficiently large at low speed rotation. It was driven with torque, or it was driven with small torque at high speed rotation.

JP 2003-111492 A

  By the way, since the switching means is composed of IGBT and a large number of diodes, the number of components is large, the circuit becomes complicated and there is a problem in miniaturizing the device, and the use of many diodes. There was a problem in securing reliability due to loss caused by voltage drop.

  Further, a failure of a switching element made of a semiconductor used for the switching means is a major obstacle in driving with a low-speed rotating large torque or driving with a high-speed rotating small torque. Therefore, there has been a demand for a failure detection method that can detect the presence or absence of a failure of the switching element used for the switching means with a simple configuration.

  The present invention has been made in order to solve the above-described problems, and the object thereof is to greatly reduce the number of constituent parts, and to reduce power loss and ensure reliability. An object of the present invention is to provide a winding switching device provided in a three-phase AC motor.

  Also provided are a short-circuit fault detection method and an open-fault detection method for a switching switching element of a winding switching device provided in a three-phase AC motor capable of detecting whether or not a switching element used for switching means has a simple configuration. There is.

The invention described in 請 Motomeko 1, each phase winding consists of first winding respectively to the second winding, the power receiving terminal to the extraction start end of the first winding, the lead end of the first winding A three-phase AC motor provided with a first neutral wire terminal at the connection portion between the first winding lead and the second winding lead end, and a second neutral wire terminal at the lead end of the second winding; A three-phase inverter circuit that inputs a DC voltage of a DC power source, converts the DC voltage into a three-phase AC power source, and applies the three-phase AC power source to a power receiving terminal of a corresponding phase of the three-phase AC motor; A first switching switching element is provided for each first neutral wire terminal of each phase, and each of the first switching switching elements operates based on a first drive signal from the first drive circuit. A first switching circuit for connecting / disconnecting the wire terminal and the first neutral wire, and a second neutral of each phase of the three-phase AC motor A second switching element is provided for each terminal, and each of the second switching elements is operated based on a second drive signal from the second drive circuit, so that the second neutral line terminal and the second neutral element are operated. A second switching circuit for connecting / disconnecting a line, and connecting a series circuit of a first diode and a first charging capacitor between the DC power source and the 1 neutral line, and A first operating power supply circuit that charges a DC voltage of a power supply to the first charging capacitor and applies the charging voltage as an operating voltage to the first drive circuit; and a series circuit of a second diode and a second charging capacitor. , Connected between the DC power supply and the second neutral line, charging the DC voltage of the DC power supply to the second charging capacitor, and applying the charging voltage to the second drive circuit as an operating voltage A second operating power supply circuit During driving of the three-phase AC motor, the first neutral wire terminal and the first neutral wire are in a disconnected state, and the second neutral wire terminal and the second neutral wire are When in the connected state, when the second neutral wire voltage of the second neutral wire is less than the DC voltage of the DC power source, the second neutral wire voltage is less than the DC voltage of the DC power source. A current path from the DC power source to the second neutral line through the series circuit of the second operating power supply circuit is formed, and the second charging capacitor is charged with a DC voltage of the DC power source; During the driving of the phase AC motor, the first neutral wire terminal and the first neutral wire are connected, and the second neutral wire terminal and the second neutral wire are not connected. When the first neutral wire voltage of the first neutral wire is less than the DC voltage of the DC power source In addition, when the first neutral line voltage is less than the DC voltage of the DC power supply, a current path from the DC power supply to the first neutral line via the series circuit of the first operating power supply circuit is formed. And a winding switching device provided in a three-phase AC motor in which the first charging capacitor is charged with a DC voltage of the DC power supply.
According to the first aspect of the present invention, it is possible to realize a three-phase AC motor having a low speed rotation large torque and a high speed rotation small torque with a simple circuit configuration.

The first operating power supply circuit includes a DC power supply → series circuit → current path composed of the first neutral line of the first diode and the first charging capacitor is formed, the first charging capacitor operating voltage of the first driving circuit The charging voltage is charged. Therefore, the first operation power supply circuit can realize the power supply circuit of the first drive circuit with a very simple circuit configuration of the first diode and the first charging capacitor.

  The second operating power supply circuit is formed with a current path composed of a DC power supply → a second diode and a second charging capacitor in series → a second neutral line, and the second charging capacitor has an operating voltage of the second drive circuit. The charging voltage is charged. Therefore, the second operation power supply circuit can realize the power supply circuit of the second drive circuit with a very simple circuit configuration of the second diode and the second charging capacitor.

The invention according to claim 2, in the winding switching device provided in the 3-phase AC motor according to claim 1, the first switching switching element provided in the first switching circuit, having a body diode Each of the second switching elements provided in the second switching circuit is a second MOS transistor having a body diode, which turns off all upper arm switching elements of the three-phase inverter circuit and A control circuit is provided that turns on at least one of the arm switching elements to charge the first and second charging capacitors of the first and second operation power supply circuits.

According to the second aspect of the present invention, the first operating power supply circuit includes a DC power supply → a series circuit of a first diode and a first charging capacitor → first neutral line → body diode of the first MOS transistor → first winding → A current path consisting of the lower arm switching element → ground is formed. The first charging capacitor is charged with a charging voltage that is the first operating voltage of the first drive circuit. Therefore, the first operation power supply circuit can realize the power supply circuit of the first drive circuit with a very simple circuit configuration of the first diode and the first charging capacitor.

  In addition, the second operating power supply circuit includes a DC power supply → a series circuit of a second diode and a second charging capacitor → second neutral line → body diode of the second MOS transistor → second winding → first winding → lower arm switching. A current path consisting of element → ground is formed. Therefore, the second operation power supply circuit can realize the power supply circuit of the second drive circuit with a very simple circuit configuration of the second diode and the second charging capacitor.

The invention according to claim 3, in the winding switching device provided in the 3-phase AC motor according to claim 2, wherein the control circuit, before driving the three-phase AC motor, said three-phase inverter circuit All upper arm switching elements are turned off and at least one of the lower arm switching elements is turned on.

According to the invention described in claim 3 , since the first and second charging capacitors are charged before driving the three-phase AC motor, the operating voltages of the first and second drive circuits are reliably driven. As a result, the three-phase AC motor can be driven more stably.

According to a fourth aspect of the present invention, in the winding switching device provided in the three-phase AC motor according to any one of the first to third aspects, the first and second operating power supply circuits have the first and second operating power supply circuits. A constant voltage circuit was provided for each charging capacitor.

According to the fourth aspect of the invention, a stable operating voltage can be supplied to the first and second drive circuits.
According to a fifth aspect of the present invention, in the winding switching device provided in the three-phase AC motor according to any one of the first to fourth aspects, a DC voltage booster circuit for boosting the DC voltage of the DC power supply is provided. The boosted voltage of the DC voltage booster circuit is applied to the first and second operation power supply circuits.

According to the fifth aspect of the present invention, a stable operating voltage can be supplied to the first and second drive circuits even when the DC voltage of the DC power supply is low.
According to a sixth aspect of the present invention, in the winding switching device provided in the three-phase AC motor according to any one of the first to third aspects, the first and second operating power supply circuits have the first and second operating power supply circuits. An operating voltage boosting circuit for boosting the charging voltage of the charging capacitor is provided.

According to the sixth aspect of the present invention, a stable operating voltage can be supplied to the first and second drive circuits even when the charging voltages of the first and second charging capacitors are low.
According to the seventh aspect of the present invention, the windings of the respective phases are composed of the first winding and the second winding, respectively, the power receiving terminal is provided at the drawing start end of the first winding, and the drawing termination end of the first winding. A three-phase AC motor provided with a first neutral wire connection terminal at the connection portion between the first winding and the lead-out end portion of the second winding, and a second neutral wire terminal at the lead-out end portion of the second winding; A three-phase inverter circuit that inputs a DC voltage of a DC power source, converts the DC voltage into a three-phase AC power source, and applies the three-phase AC power source to a power receiving terminal of a corresponding phase of the three-phase AC motor; A first switching switching element is provided for each first neutral wire terminal of each phase, and each of the first switching switching elements operates based on a first drive signal from the first drive circuit. A first switching circuit for connecting / disconnecting the wire terminal and the first neutral wire; and a second of each phase of the three-phase AC motor A second switching element is provided for each of the neutral line terminals, and each of the second switching elements operates based on a second drive signal from the second drive circuit, and the second neutral line terminal and the second neutral line terminal are connected to the second neutral line terminal. A short-circuit fault detecting method for a switching switching element of a winding switching device provided in a three-phase AC motor comprising a second switching circuit for connecting / disconnecting a neutral wire to a power receiving terminal of each phase. , Connecting a connection point between a pull-up resistor and a pull-down resistor each formed of a series circuit, connecting the other end of the pull-up resistor to the DC power supply, and grounding the other end of the pull-down resistor to the ground. The neutral wire is grounded via the first voltage detection resistor, and the second neutral wire is grounded via the second voltage detection resistor, and all upper arms of the three-phase inverter circuit Switchon When the element and all lower arm switching elements are turned off and all the first and second switching elements of the first and second switching circuits are turned off, the first neutral line or the second neutral line When one of the voltages is an intermediate voltage, it is determined that one of the switching elements of the switching circuit on the side that has become the intermediate voltage has a short circuit failure, and the voltage on the first and second neutral lines is the intermediate voltage. When the voltage is lower, it is determined that all the first and second switching elements are not short-circuited.

According to the seventh aspect of the present invention, the upper and lower arm switching elements of the three-phase inverter circuit are controlled to be turned off, and only the first and second switching elements of the first and second switching circuits are controlled to be turned off. Thus, it is possible to detect whether the switching switching element of either the first switching circuit or the second switching circuit is short-circuited.

According to an eighth aspect of the present invention, in the short-circuit fault detecting method for the switching element of the winding switching device provided in the three-phase AC motor according to the seventh aspect , the first or second switching circuit includes the first or second switching circuit. When it is determined that any of the second switching elements is short-circuited, only the upper arm switching elements of any one of the upper arm switching elements of the three-phase inverter circuit are sequentially turned on, When the voltages of the first and second neutral lines become higher than the intermediate voltage, the switching circuit is a switching circuit that is determined to have a short-circuit failure, and the phase switching corresponding to the upper arm switching element that is turned on at that time Judge that the element is short-circuited.

According to the eighth aspect of the present invention, in the switching circuit that is determined to be a short circuit fault, by sequentially turning on only the upper arm switching element of any one phase of all the upper arm switching elements of the three-phase inverter circuit. Therefore, it is possible to detect whether or not the switching element of the phase corresponding to the upper arm switching element that is turned on at the time has a short circuit failure.

According to a ninth aspect of the present invention, in the short-circuit fault detecting method for the switching switching element of the winding switching device provided in the three-phase AC motor according to the seventh or eighth aspect , the first and second switching circuits are provided. Each of the first and second switching elements is a MOS transistor.

According to the ninth aspect of the present invention, it is possible to detect whether each MOS transistor provided in the first and second switching circuits has a short circuit failure.
The invention according to claim 1 0, each phase winding consists of first winding respectively to the second winding, the power receiving terminal to the extraction start end of the first winding, the lead end of the first winding Three-phase AC motor provided with a first neutral wire connection terminal at the connection portion between the first winding portion and the lead-out start end portion of the second winding, and a second neutral wire terminal at the lead end portion of the second winding A three-phase inverter circuit that inputs a DC voltage of a DC power source, converts the DC voltage into a three-phase AC power source, and applies the three-phase AC power source to a power receiving terminal of a corresponding phase of the three-phase AC motor; and the three-phase AC motor A first switching switching element is provided for each first neutral wire terminal of each phase, and the first switching switching elements are operated on the basis of the first drive signal from the first drive circuit. A first switching circuit for connecting / disconnecting the neutral wire terminal and the first neutral wire; and a first switching circuit for each phase of the three-phase AC motor. A second switching switching element is provided for each of the two neutral wire terminals, and each of the second switching switching elements is operated based on a second drive signal from the second drive circuit; An open fault detection method for a switching switching element of a winding switching device provided in a three-phase AC motor comprising a second switching circuit for connecting / disconnecting a second neutral wire to the second neutral line, A terminal is connected to a connection point of a pull-up resistor and a pull-down resistor each consisting of a series circuit, the other end of the pull-up resistor is connected to the DC power supply, and the other end of the pull-down resistor is grounded to the ground. The first neutral line is grounded via a first voltage detection resistor, and the second neutral line is grounded via a second voltage detection resistor, and the first switching circuit One switching switching element When detecting a pun failure, all the first switching elements of the first switching circuit are turned on, all the second switching elements of the second switching circuit are turned off, and all the three-phase inverter circuits are When only the upper arm switching element of any one of the upper arm switching elements is sequentially turned on and the voltage of the first neutral line becomes equal to or lower than the intermediate voltage, the upper arm switching element that is turned on at that time When the voltage of the first neutral line becomes a higher voltage than the intermediate voltage, it is determined that the first switching switching element of the phase corresponding to It is determined that the first switching element of the phase corresponding to the element is not open failure, and the second switching element of the second switching circuit is opened. When detecting a failure, all the second switching elements of the second switching circuit are turned on, all the first switching elements of the first switching circuit are turned off, and all the three-phase inverter circuits When only the upper arm switching element of any one of the upper arm switching elements is sequentially turned on and the voltage of the second neutral line becomes lower than the intermediate voltage, the upper arm switching element that is turned on at that time When it is determined that the second switching element of the corresponding phase has an open failure, and the voltage of the second neutral line becomes higher than the intermediate voltage, the upper arm switching element that is turned on at that time It is determined that the second switching element of the phase corresponding to is not open failure.

According to the invention of claim 1 0, the other to one of the on state one of the first and second switching switching elements of the first and second switching circuits are turned off, on all of the 3-phase inverter circuit By sequentially turning on only the upper arm switching element of any one phase of the arm switching element, the phase corresponding to the upper arm switching element that is turned on at that time, the first or second switching in the on state It can be detected whether the switching element has an open failure.

The invention of claim 1 1, in the open failure detection method of the switching the switching element of the winding switching device provided in the 3-phase AC motor according to claim 1 0, provided in the first and second switching circuits Each of the first and second switching elements is a MOS transistor.

  According to the eleventh aspect of the present invention, it is possible to detect whether or not each MOS transistor provided in the first and second switching circuits has an open failure.

  According to the present invention, it is possible to greatly reduce the number of components to be configured, thereby reducing power loss and ensuring reliability. Further, it is possible to detect the presence or absence of a failure of the switching element used for the switching means with a simple configuration.

The partial electric circuit diagram of the coil | winding switching apparatus of the three-phase alternating current motor of 1st Embodiment. Similarly, a partial electric circuit diagram of a winding switching device of a three-phase AC motor. Similarly, a partial electric circuit diagram of a winding switching device of a three-phase AC motor. Electrical circuit diagram of star connection of winding for high-speed rotation. The electrical circuit diagram of the star connection of the coil | winding for low speed rotation. The partial electric block circuit diagram of the coil | winding switching apparatus of a three-phase alternating current motor similarly. (A) is a waveform diagram of the first neutral wire voltage of the first neutral wire during high-speed rotation, and (b) is a waveform diagram of the second neutral wire voltage of the second neutral wire during high-speed rotation. (A) is a waveform diagram of the first neutral wire voltage of the first neutral wire during low-speed rotation, and (b) is a waveform diagram of the second neutral wire voltage of the second neutral wire during low-speed rotation. The electric circuit diagram of the 1st and 2nd operation | movement power supply circuit which shows another example of 1st Embodiment. The electric circuit diagram of the 1st and 2nd operation | movement power supply circuit which shows another example of 1st Embodiment. The electric circuit diagram of the 1st and 2nd operation | movement power supply circuit which shows another example of 1st Embodiment. The partial electric circuit diagram of the coil | winding switching apparatus of the three-phase alternating current motor of 2nd Embodiment. The partial electric block circuit diagram of the coil | winding switching apparatus of the three-phase alternating current motor of 2nd Embodiment.

(First embodiment)
A first embodiment embodying a winding switching device for a three-phase AC motor according to the present invention will be described below with reference to FIGS.

  1 to 3 show an electric circuit of the winding switching device 1 of the three-phase AC motor M. FIG. The winding switching device 1 converts the DC power source G into a three-phase AC power source for the three-phase AC motor M and supplies it to the windings of each phase of the three-phase AC motor M. There are provided first and second switching circuits 11 and 12 for switching the windings of each phase to make high speed small torque and low speed large torque.

  As shown in FIG. 2, the winding switching device 1 includes a first drive circuit 21 that drives the first switch circuit 11 and a first operation power supply circuit 31 that supplies operation power to the first drive circuit 21. I have. Further, as shown in FIG. 3, the winding switching device 1 includes a second drive circuit 22 that drives the second switch circuit 12 and a second operation power supply circuit 32 that supplies the operation power of the second drive circuit 22. I have.

(Three-phase AC motor M)
The U-phase winding of the three-phase AC motor M is wound so that the two windings of the first U-phase winding U1 and the second U-phase winding U2 are connected in series for each U-phase tooth. Configured.

  More specifically, the first U-phase winding U1 is wound around a U-phase tooth by a predetermined number, and its drawing start end U1a and drawing end U1b are drawn out to the rear side. Similarly, a predetermined number of second U-phase windings U2 are wound around U-phase teeth, and the drawing start end U2a and the drawing end U2b are drawn out to the rear side.

  In each of the teeth, the drawing end portion U1b of the first U-phase winding U1 drawn to the rear side and the drawing start end portion U2a of the second U-phase winding U2 are electrically connected to each other.

  The first U-phase winding U1 wound around each U-phase tooth is electrically connected to each other in parallel, and the second U-phase winding U2 wound around each U-phase tooth is mutually connected. They are electrically connected in parallel.

  For convenience of explanation, only the first U-phase winding U1 and the second U-phase winding U2 wound around one U-phase tooth are illustrated in the electric circuits of FIGS. Hereinafter, for convenience of explanation, the U-phase windings are collectively referred to as a first U-phase winding U1 and a second U-phase winding U2.

  And the power receiving terminal Tu provided at the front-end | tip of the extraction | drawer start end part U1a of the 1st U-phase coil | winding U1 is connected to the inverter circuit 10, and the U-phase alternating current power supply Vu is input. Further, the connection terminal Tu1 that connects the leading end portion U1b of the first U-phase winding U1 and the leading end portion U2a of the second U-phase winding U2 is connected to the first switching circuit 11. Furthermore, an external terminal Tu2 provided at the tip of the leading end portion U2b of the second U-phase winding U2 is connected to the second switching circuit 12.

  Further, the V-phase winding of the three-phase AC motor M is wound so that the two windings of the first V-phase winding V1 and the second V-phase winding V2 are connected in series for each V-phase tooth. It is configured to be turned.

  More specifically, the first V-phase winding V1 is wound around a V-phase tooth by a predetermined number, and its drawing start end V1a and drawing end V1b are drawn out to the rear side. Similarly, the second V-phase winding V2 is wound around a V-phase tooth by a predetermined number, and its drawing start end V2a and drawing end V2b are drawn out to the rear side.

  In each of the teeth, the leading end portion V1b of the first V-phase winding V1 drawn to the rear side and the leading start end portion V2a of the second V-phase winding V2 are electrically connected to each other.

  Similarly, the first V-phase winding V1 wound around each V-phase tooth is electrically connected in parallel to each other, and the second V-phase winding V2 wound around each V-phase tooth. Are electrically connected to each other in parallel.

For convenience of explanation, in the electric circuits of FIGS. 1 to 3, only the first V-phase winding V1 and the second V-phase winding V2 wound around one V-phase tooth are illustrated.
Hereinafter, for convenience of explanation, the V-phase windings are collectively referred to as a first V-phase winding V1 and a second V-phase winding V2.

  And the power receiving terminal Tv provided at the front-end | tip of the extraction | drawer start end part V1a of the 1st V-phase coil | winding V1 is connected to the inverter circuit 10, and V-phase alternating current power supply Vv is input. In addition, a connection terminal Tv1 that connects the leading end portion V1b of the first V-phase winding V1 and the leading end portion V2a of the second V-phase winding V2 is connected to the first switching circuit 11. Furthermore, the external terminal Tv2 provided at the tip of the lead terminal portion V2b of the second V-phase winding V2 is connected to the second switching circuit 12.

  Further, the W-phase winding of the three-phase AC motor M is wound so that the two windings of the first W-phase winding W1 and the second W-phase winding W2 are connected in series for each W-phase tooth. It is configured to be turned.

  Specifically, the first W-phase winding W1 is wound around a W-phase tooth by a predetermined number, and its drawing start end portion W1a and drawing end portion W1b are drawn out to the rear side. Similarly, the second W-phase winding W2 is wound around the W-phase teeth by a predetermined number, and its drawing start end W2a and drawing end W2b are drawn out to the rear side.

  In each of the teeth, the drawing end portion W1b of the first W-phase winding W1 drawn to the rear side and the drawing start end portion W2a of the second W-phase winding W2 are electrically connected to each other.

  Similarly, the first W-phase winding W1 wound around each W-phase tooth is electrically connected in parallel to each other, and the second W-phase winding W2 wound around each W-phase tooth. Are electrically connected to each other in parallel.

For convenience of explanation, in the electric circuits of FIGS. 1 to 3, only the first W-phase winding W1 and the second W-phase winding W2 wound around one W-phase tooth are illustrated.
Hereinafter, for convenience of explanation, the W-phase windings are collectively referred to as a first W-phase winding W1 and a second W-phase winding W2.

  And the power receiving terminal Tw provided at the front-end | tip of the drawer | drawing-out start part W1a of the 1st W-phase coil | winding W1 is connected to the inverter circuit 10, and the W-phase alternating current power supply Vw is input. In addition, a connection terminal Tw1 that connects the leading end portion W1b of the first W-phase winding W1 and the leading end portion W2a of the second W-phase winding W2 is connected to the first switching circuit 11. Furthermore, an external terminal Tw2 provided at the tip of the leading end portion W2b of the second W-phase winding W2 is connected to the second switching circuit 12.

(Inverter circuit 10)
The inverter circuit 10 is a three-phase inverter circuit. The inverter circuit 10 includes a series circuit of U-phase upper arm and lower arm U-phase switching elements Qa and Qb, a series circuit of V-phase upper arm and lower arm V-phase switching elements Qc and Qd, and a W-phase circuit. The upper arm and the lower arm W-phase switching elements Qe and Qf are connected in parallel to each other, and a DC voltage Vdd from the DC power supply G is applied thereto.

  U-phase upper arm and lower arm U-phase switching elements Qa and Qb are formed of N-channel MOS transistors. The source terminal of the upper arm U-phase switching element Qa and the drain terminal of the lower arm U-phase switching element Qb are connected, and the connection point Na is connected to the power receiving terminal Tu of the U-phase winding. The upper arm U-phase switching element Qa has a drain terminal connected to the positive terminal of the DC power supply G, and the lower arm U-phase switching element Qb has a source terminal connected to the negative terminal of the DC power supply G and grounded. Yes.

  Similarly, V-phase upper arm and lower arm V-phase switching elements Qc and Qd are formed of N-channel MOS transistors. The source terminal of the upper arm V-phase switching element Qc and the drain terminal of the lower arm V-phase switching element Qd are connected, and the connection point Nb is connected to the power receiving terminal Tv of the V-phase winding. The upper arm V-phase switching element Qc has a drain terminal connected to the positive terminal of the DC power supply G, and the lower arm V-phase switching element Qd has a source terminal connected to the negative terminal of the DC power supply G and grounded. Yes.

  The W-phase upper arm and lower arm W-phase switching elements Qe and Qf are similarly formed of N-channel MOS transistors. The source terminal of the upper arm W-phase switching element Qe and the drain terminal of the lower arm W-phase switching element Qf are connected, and the connection point Nc is connected to the power receiving terminal Tw of the W-phase winding. The upper arm W-phase switching element Qe has a drain terminal connected to the positive terminal of the DC power supply G, and the lower arm W-phase switching element Qf has a source terminal connected to the negative terminal of the DC power supply G and grounded. Yes.

  Drive signals S1 to S6 from the inverter control circuit 2 are input to the gate terminals of the switching elements Qa to Qf, respectively. Based on the drive signals S1 to S6 from the inverter control circuit 2, the switching elements Qa to Qf are turned on / off at a predetermined timing, and the inverter circuit 10 is connected to the DC voltage Vdd (in this embodiment) of the DC power supply G. 12V) is converted into a three-phase AC power source Vu, Vv, Vw and supplied to each phase of the three-phase AC motor M.

(First switching circuit 11)
As shown in FIGS. 1 and 2, the first switching circuit 11 includes a first U-phase switching element Q1, a first V-phase switching element Q2, and a first W-phase switching element Q3.

  The first U-phase switching element Q1 is an MOS transistor made of an N-channel MOS transistor and provided with a body diode D between the source and drain. The drain terminal of the first U-phase switching element Q1 is connected to the connection terminal Tu1 of the U-phase winding. The source terminal of the first U-phase switching element Q1 is connected to the first neutral line NL1.

  The gate terminal of the first U-phase switching element Q1 is connected to the first drive circuit 21 via a resistor R1 and a resistor R2, as shown in FIG. A series circuit for overvoltage protection composed of a diode D1 and a Zener diode TD1 is connected between the connection point N1 of the resistors R1 and R2 and the drain terminal of the first U-phase switching element Q1. A resistor R3 is connected between the connection point N1 and the source terminal of the first U-phase switching element Q1.

  As shown in FIG. 2, the first drive signal SD1 from the first drive circuit 21 is input to the gate terminal of the first U-phase switching element Q1 via the resistor R1 and the resistor R2.

  Similarly, the first V-phase switching element Q2 is an MOS transistor made of an N-channel MOS transistor and provided with a body diode D between the source and drain. The drain terminal of the first V-phase switching element Q2 is connected to the connection terminal Tv1 of the V-phase winding. The source terminal of the first V-phase switching element Q2 is connected to the first neutral line NL1.

  The gate terminal of the first V-phase switching element Q2 is connected to the first drive circuit 21 via a resistor R4 and a resistor R5, as shown in FIG. Between the connection point N2 of the resistor R4 and the resistor R5 and the drain terminal of the first V-phase switching element Q2, a series circuit for overvoltage protection including a diode D2 and a Zener diode TD2 is connected. A resistor R6 is connected between the connection point N2 and the source terminal of the first V-phase switching element Q2.

  As shown in FIG. 2, the gate terminal of the first V-phase switching element Q2 is input to the gate terminal of the first U-phase switching element Q1 from the first drive circuit 21 via the resistor R4 and the resistor R5. A drive signal SD1 is input.

  Similarly, the first W-phase switching element Q3 is an MOS transistor made of an N-channel MOS transistor and provided with a body diode D between the source and the drain. The drain terminal of the first W-phase switching element Q3 is connected to the connection terminal Tw1 of the W-phase winding. The source terminal of the first W-phase switching element Q3 is connected to the first neutral line NL1.

  The gate terminal of the first W-phase switching element Q3 is connected to the first drive circuit 21 via a resistor R7 and a resistor R8, as shown in FIG. Between the connection point N3 of the resistors R7 and R8 and the drain terminal of the first W-phase switching element Q3, a series circuit for overvoltage protection composed of a diode D3 and a Zener diode TD3 is connected. A resistor R9 is connected between the connection point N3 and the source terminal of the first W-phase switching element Q3.

  As shown in FIG. 2, the gate terminal of the first W-phase switching element Q3 is input to the gate terminal of the first U-phase switching element Q1 from the first drive circuit 21 via the resistor R7 and the resistor R8. One drive signal SD1 is input.

  Therefore, when the first drive signal SD1 of high level is output from the first drive circuit 21, the first U-phase switching element Q1, the first V-phase switching element Q2, and the first W-phase switching element Q3 are turned on and connected to the connection terminal. Tu1, Tv1, Tw1 and the first neutral line NL1 are connected.

  Conversely, when the first drive signal SD1 at the low level is output from the first drive circuit 21, the first U-phase switching element Q1, the first V-phase switching element Q2, and the first W-phase switching element Q3 are turned off and connected. The connection between the terminals Tu1, Tv1, Tw1 and the first neutral line NL1 is cut off.

(Second switching circuit 12)
As shown in FIGS. 1 and 3, the second switching circuit 12 includes a second U-phase switching element Q4, a second V-phase switching element Q5, and a second W-phase switching element Q6.

  The second U-phase switching element Q4 is an MOS transistor made of an N-channel MOS transistor and provided with a body diode D between the source and drain. The drain terminal of the second U-phase switching element Q4 is connected to the external terminal Tu2 of the U-phase winding. The source terminal of the second U-phase switching element Q4 is connected to the second neutral line NL2.

  The gate terminal of the second U-phase switching element Q4 is connected to the second drive circuit 22 via a resistor R11 and a resistor R12, as shown in FIG. Between the connection point N4 of the resistors R11 and R12 and the drain terminal of the second U-phase switching element Q4, a series circuit for overvoltage protection composed of a diode D4 and a Zener diode TD4 is connected. A resistor R13 is connected between the connection point N4 and the source terminal of the second U-phase switching element Q4.

  As shown in FIG. 3, the second drive signal SD2 from the second drive circuit 22 is input to the gate terminal of the second U-phase switching element Q4 via the resistor R11 and the resistor R12.

  Similarly, second V-phase switching element Q5 is an N-channel MOS transistor, and is a MOS transistor provided with a body diode D between the source and drain. The drain terminal of the second V-phase switching element Q5 is connected to the external terminal Tv2 of the V-phase winding. The source terminal of the second V-phase switching element Q5 is connected to the second neutral line NL2.

  The gate terminal of the second V-phase switching element Q5 is connected to the second drive circuit 22 via a resistor R14 and a resistor R15 as shown in FIG. Between the connection point N5 of the resistors R14 and R15 and the drain terminal of the second V-phase switching element Q5, a series circuit for overvoltage protection composed of a diode D5 and a Zener diode TD5 is connected. A resistor R16 is connected between the connection point N5 and the source terminal of the second V-phase switching element Q5.

  As shown in FIG. 3, the gate terminal of the second V-phase switching element Q5 is input to the gate terminal of the second U-phase switching element Q4 from the second drive circuit 22 via the resistor R14 and the resistor R15. Two drive signals SD2 are input.

  Similarly, the second W-phase switching element Q6 is an MOS transistor made of an N-channel MOS transistor and provided with a body diode D between the source and drain. The drain terminal of the second W-phase switching element Q6 is connected to the external terminal Tw2 of the W-phase winding. The source terminal of the second W-phase switching element Q6 is connected to the second neutral line NL2.

  Further, the gate terminal of the second W-phase switching element Q6 is connected to the second drive circuit 22 via a resistor R17 and a resistor R18 as shown in FIG. Between the connection point N6 of the resistor R17 and the resistor R18 and the drain terminal of the second W-phase switching element Q6, a series circuit for overvoltage protection composed of a diode D6 and a Zener diode TD6 is connected. A resistor R19 is connected between the connection point N6 and the source terminal of the second W-phase switching element Q6.

  As shown in FIG. 3, the gate terminal of the second W-phase switching element Q6 is input to the gate terminal of the second U-phase switching element Q4 from the second drive circuit 22 via the resistor R17 and the resistor R18. Two drive signals SD2 are input.

  Accordingly, when the second drive signal SD2 at the high level is output from the second drive circuit 22, the second U-phase switching element Q4, the second V-phase switching element Q5, and the second W-phase switching element Q6 are turned on and the external terminal Tu2, Tv2, Tw2 and the second neutral line NL2 are connected.

  On the other hand, when the second drive signal SD2 at the low level is output from the second drive circuit 22, the second U-phase switching element Q4, the second V-phase switching element Q5, and the second W-phase switching element Q6 are turned off and externally supplied. The connection between the terminals Tu2, Tv2, Tw2 and the second neutral line NL2 is cut off.

  Incidentally, when the three-phase AC motor M is driven, the first drive signal SD1 of the first drive circuit 21 and the second drive signal SD2 of the second drive circuit 22 are complementary signals. That is, when the first drive signal SD1 is at a high level, the second drive signal SD2 is at a low level, and when the first drive signal SD1 is at a low level, the second drive signal SD2 is at a high level.

  Therefore, when the first drive signal SD1 is at a high level, the switching elements Q1 to Q3 of the first switching circuit 11 are turned on, and the switching elements Q4 to Q6 of the second switching circuit 12 are turned off. As a result, the winding structure of the three-phase AC motor M is such that the U phase is a first U phase winding U1, the V phase is a first V phase winding V1, and the W phase is a first W phase winding W1. HS star connection. FIG. 4 shows an equivalent circuit thereof.

  Conversely, when the second drive signal SD2 is at a high level, the switching elements Q4 to Q6 of the second switching circuit 12 are turned on, and the switching elements Q1 to Q3 of the first switching circuit 11 are turned off. Thus, the wiring structure of the three-phase AC motor M is such that the U phase is a series circuit of the first and second U phase windings U1 and U2, the V phase is a series circuit of the first and second V phase windings V1 and V2, and W The phase is a star connection of a low-speed rotation winding LS composed of a series circuit of first and second W-phase windings W1 and W2. FIG. 5 shows an equivalent circuit thereof.

  Therefore, the three-phase AC motor M of the present embodiment can switch the winding structure between the high-speed rotation winding HS and the low-speed rotation winding LS. Various types of motor characteristics can be obtained.

  In the above embodiment, the MOS transistors Q1 to Q6 having the body diode D are used as the switching elements of the first and second switching circuits 11 and 12, but the MOS transistors Q1 to Q6 having the body diode D are used. Also good.

(First drive circuit 21)
Next, the first drive circuit 21 that drives the first switching circuit 11 will be described.
As shown in FIG. 2, the first drive circuit 21 includes an output circuit including first and second MOS transistors Q11 and Q12, a photocoupler including a first infrared light emitting element D1a and a first infrared light receiving element D1b, and a first amplifier 21a. The first logic circuit 21b.

  The first and second MOS transistors Q11 and Q12 constituting the output circuit are N-channel MOS transistors, the source terminal of the first MOS transistor Q11 and the drain terminal of the second MOS transistor Q12 are connected, and the first drive is performed from the connection point T1. A signal SD1 is output. The drain terminal of the first MOS transistor Q11 is connected to the plus terminal Tp1 of the first operating power supply circuit 31 of the first drive circuit 21. The source terminal of the second MOS transistor Q12 is connected to the negative terminal Tn1 of the first operating power supply circuit 31 of the first drive circuit 21 and to the first neutral line NL1 of the first switching circuit 11.

  The gate terminals of the first and second MOS transistors Q11 and Q12 are respectively connected to the first logic circuit 21b, and the first and second determination signals SJ1 and SJ2 are input to the respective gate terminals. The first and second determination signals SJ1 and SJ2 are complementary signals that are turned off when one of the first and second MOS transistors Q11 and Q12 is turned on.

  Accordingly, when the first MOS transistor Q11 is on, the second MOS transistor Q12 is off, and the high-level first drive signal SD1 is output from the connection point T1. On the other hand, when the first MOS transistor Q11 is off, the second MOS transistor Q12 is on, and the low-level first drive signal SD1 is output from the connection point T1.

  The first infrared light emitting element D1a constituting the photocoupler is connected to the first neutral line switching control circuit 3, and is controlled by the first neutral line switching control circuit 3 to emit infrared rays.

  More specifically, the first neutral wire switching control circuit 3 is connected to the first infrared light emitting element D1a when the winding structure of the three-phase AC motor M is changed to the star connection of the high-speed rotation winding HS shown in FIG. Current is to flow. Accordingly, the first infrared light emitting element D1a emits infrared light. On the contrary, when the first neutral wire switching control circuit 3 uses the winding structure of the three-phase AC motor M as the star connection of the low-speed rotation winding LS shown in FIG. It is supposed not to flow. Accordingly, the first infrared light emitting element D1a does not emit infrared light.

  The first infrared light receiving element D1b constituting the photocoupler receives the infrared light emitted from the first infrared light emitting element D1a, conducts, and outputs the current as a detection current to the first amplifier 21a in the next stage. That is, when the first infrared light emitting element D1a emits infrared light, the first infrared light receiving element D1b receives the infrared light and outputs a detection current to the first amplifier 21a. On the other hand, when the first infrared light emitting element D1a is not emitting infrared light, the first infrared light receiving element D1b does not receive infrared light and therefore does not output a detection current to the first amplifier 21a.

  The first amplifier 21a amplifies the detection current and outputs the detection current to the first logic circuit 21b. The first logic circuit 21b outputs first and second determination signals SJ1 and SJ2 indicating whether or not the first infrared light emitting element D1a emits infrared light based on the detection current input by the first amplifier 21a.

  The first logic circuit 21b outputs a high-level first determination signal SJ1 and a low-level second determination signal SJ2 when the first infrared light-emitting element D1a emits infrared light. As a result, the first MOS transistor Q11 is turned on, the second MOS transistor Q12 is turned off, and the high-level first drive signal SD1 is output from the connection point N1.

  That is, the first infrared light emitting element D1a emits light, and the high-level first drive signal SD1 is output from the connection point T1, whereby the winding structure of the three-phase AC motor M is shown in FIG. It can be a star connection of the line HS.

  On the other hand, when the first infrared light emitting element D1a does not emit infrared light, the first logic circuit 21b outputs a low-level first determination signal SJ1 and a high-level second determination signal SJ2. As a result, the first MOS transistor Q11 is turned off, the second MOS transistor Q12 is turned on, and the low-level first drive signal SD1 is output from the connection point T1.

  In other words, the first infrared light emitting element D1a is not caused to emit light, and the low-level first drive signal SD1 is output from the connection point N1, so that the winding structure of the three-phase AC motor M is for low-speed rotation shown in FIG. It can be a star connection of the winding LS.

(Second drive circuit 22)
Next, the second drive circuit 22 that drives the second switching circuit 12 will be described.
As shown in FIG. 3, the second drive circuit 22 includes an output circuit including third and fourth MOS transistors Q13 and Q14, a photocoupler including a second infrared light emitting element D2a and a second infrared light receiving element D2b, and a second amplifier 22a. The second logic circuit 22b.

  The third and fourth MOS transistors Q13 and Q14 constituting the output circuit are N-channel MOS transistors. The source terminal of the third MOS transistor Q13 and the drain terminal of the fourth MOS transistor Q14 are connected, and the second drive is performed from the connection point T2. A signal SD2 is output. The drain terminal of the third MOS transistor Q13 is connected to the plus terminal Tp2 of the second operation power supply circuit 32 of the second drive circuit 22. The source terminal of the fourth MOS transistor Q14 is connected to the minus terminal Tn2 of the second operation power supply circuit 32 of the second drive circuit 22, and is also connected to the second neutral line NL2 of the second switching circuit 12.

  The gate terminals of the third and fourth MOS transistors Q13 and Q14 are respectively connected to the second logic circuit 22b, and the third and fourth determination signals SJ3 and SJ4 are input to the respective gate terminals. The third and fourth determination signals SJ3 and SJ4 are complementary signals, and are signals that turn off when one of the third and fourth MOS transistors Q13 and Q14 is on.

  Therefore, when the third MOS transistor Q13 is on, the fourth MOS transistor Q14 is off, and the high-level second drive signal SD2 is output from the connection point T2. On the other hand, when the third MOS transistor Q13 is off, the fourth MOS transistor Q14 is on, and the low-level second drive signal SD2 is output from the connection point T2.

  The second infrared light emitting element D2a constituting the photocoupler is connected to the second neutral line switching control circuit 4, and is controlled by the second neutral line switching control circuit 4 to emit infrared light.

  More specifically, the second neutral wire switching control circuit 4 uses the second infrared light emitting element D2a when the winding structure of the three-phase AC motor M is changed to the star connection of the low-speed rotation winding LS shown in FIG. Current is to flow. Accordingly, the second infrared light emitting element D2a emits infrared light. On the contrary, when the second neutral wire switching control circuit 4 uses the winding structure of the three-phase AC motor M as the star connection of the high-speed rotation winding HS shown in FIG. It is supposed not to flow. Accordingly, the second infrared light emitting element D2a does not emit infrared light.

  The second infrared light receiving element D2b constituting the photocoupler receives the infrared light emitted from the second infrared light emitting element D2a, conducts, and outputs the current as a detection current to the second amplifier 22a in the next stage. That is, when the second infrared light emitting element D2a emits infrared light, the second infrared light receiving element D2b receives the infrared light and outputs a detection current to the second amplifier 22a. On the other hand, when the second infrared light emitting element D2a is not emitting infrared light, the second infrared light receiving element D2b does not receive infrared light, and therefore does not output a detection current to the second amplifier 22a.

  The second amplifier 22a amplifies the detection current and outputs the detection current to the second logic circuit 22b. The second logic circuit 22b outputs third and fourth determination signals SJ3 and SJ4 indicating whether the second infrared light emitting element D2a emits infrared light based on the detection current input by the second amplifier 22a.

  When the second infrared light emitting element D2a emits infrared light, the second logic circuit 22b outputs a high level third determination signal SJ3 and also outputs a low level fourth determination signal SJ4. As a result, the third MOS transistor Q13 is turned on, the fourth MOS transistor Q14 is turned off, and the high-level second drive signal SD2 is output from the connection point T2.

  That is, by causing the second infrared light emitting element D2a to emit light and outputting the high-level second drive signal SD2 from the connection point T2, the winding structure of the three-phase AC motor M is reduced to the low-speed rotation winding shown in FIG. It can be a star connection of the line LS.

  On the other hand, the second logic circuit 22b outputs a low-level third determination signal SJ3 and a high-level fourth determination signal SJ4 when the second infrared light emitting element D2a does not emit infrared light. As a result, the third MOS transistor Q13 is turned off, the fourth MOS transistor Q14 is turned on, and the low-level second drive signal SD2 is output from the connection point T2.

  In other words, the second infrared light emitting element D2a is not caused to emit light, and the low-level second drive signal SD2 is output from the connection point N2, so that the winding structure of the three-phase AC motor M is for high-speed rotation shown in FIG. The winding HS can be a star connection.

  The first infrared light emitting element D1a and the second infrared light emitting element D2a do not emit light at the same time when the three-phase AC motor M is driven. When either one emits light, the other does not emit light. In addition, the first neutral line switching control circuit 3 and the second neutral line switching control circuit 4 are controlled.

(First operation power supply circuit 31)
Next, the first operation power supply circuit 31 of the first drive circuit 21 will be described.
As shown in FIG. 2, the first operating power supply circuit 31 includes a first charging capacitor Ca. The first charging capacitor Ca has a plus terminal at the plus terminal Tp1 of the first operating power supply circuit 31, and a minus terminal at the minus terminal Tn1 of the first operating power supply circuit 31. The terminal Tn1 is connected to the first drive circuit 21. Then, the charging voltage charged in the first charging capacitor Ca becomes a first operating voltage Vd1 (12V in the present embodiment) for operating the first driving circuit 21, and is applied to the first driving circuit 21. .

  The plus terminal Tp1 of the first charging capacitor Ca is connected to the plus terminal of the DC power supply G via the first diode Da and the first resistor Ra. On the other hand, the negative terminal Tn1 of the first charging capacitor Ca is connected to the first neutral line NL1 of the first switching circuit 11.

  In the present embodiment, the switching elements Q1 to Q6 of the first and second switching circuits 11 and 12 are turned off, and only the lower arm U-phase switching element Qb of the inverter circuit 10 is turned on. 1 Charging capacitor Ca is charged before being driven.

  Accordingly, the DC power source G → the first resistor Ra → the first diode Da → the first charging capacitor Ca → the first neutral line NL1 → the body diode D of the first U-phase switching element Q1 → the first U-phase winding U1 → the lower arm. A current path including the U-phase switching element Qb → ground is formed. By forming the formed current path, the first charging capacitor Ca is charged to the first operating voltage Vd1 with the DC voltage Vdd (= 12V) of the DC power supply G.

  When the first neutral line NL1 becomes less than the DC voltage Vdd (= 12V) of the DC power supply G while the three-phase AC motor M is being driven, the DC power supply G → the first resistor Ra → the first diode Da → A current path including the first charging capacitor Ca → the first neutral line NL1 is formed. By forming the formed current path, the first charging capacitor Ca is charged to the first operating voltage Vd1 with the DC voltage Vdd (= 12V) of the DC power supply G.

  The first charging capacitor Ca is connected to the first Zener diode TDa in parallel. The first Zener diode TDa protects the first charging capacitor Ca from damage due to overcharging.

(Second operation power supply circuit 32)
Next, the second operation power supply circuit 32 of the second drive circuit 22 will be described.
As shown in FIG. 3, the second operating power supply circuit 32 has a second charging capacitor Cb. The second charging capacitor Cb has a plus terminal serving as the plus terminal Tp2 of the second operating power supply circuit 32, and a minus terminal serving as the minus terminal Tn2 of the second operating power supply circuit 32, and is minus with the plus terminal Tp2. The terminal Tn2 is connected to the second drive circuit 22. The charging voltage charged in the second charging capacitor Cb is applied to the second drive circuit 22 as a second operating voltage Vd2 for operating the second drive circuit 22.

  The plus terminal Tp2 of the second charging capacitor Cb is connected to the plus terminal of the DC power supply G via the second diode Db and the second resistor Rb. On the other hand, the minus terminal Tn2 of the second charging capacitor Cb is connected to the second neutral line NL2 of the second switching circuit 12.

  In the present embodiment, the switching elements Q1 to Q6 of the first and second switching circuits 11 and 12 are turned off, and only the lower arm U-phase switching element Qb of the inverter circuit 10 is turned on. 1 Charging capacitor Ca is charged before being driven.

  As a result, DC power supply G → second resistance Rb → second diode Db → second charging capacitor Cb → second neutral line NL2 → body diode D of second U-phase switching element Q4 → second U-phase winding U2 → first U A current path including the phase winding U1 → the lower arm U-phase switching element Qb → the ground is formed. By forming this current path, the second charging capacitor Cb is charged to the second operating voltage Vd2 with the DC voltage Vdd (= 12V) of the DC power supply G.

  When the second neutral line NL2 becomes less than the DC voltage Vdd (= 12V) of the DC power supply G while the three-phase AC motor M is being driven, the DC power supply G → second resistor Rb → second diode Db → A current path including the second charging capacitor Cb → the second neutral line NL2 is formed. By forming this current path, the second charging capacitor Cb is charged to the second operating voltage Vd2 with the DC voltage Vdd (= 12V) of the DC power supply G.

  The second charging capacitor Cb is connected in parallel with a second Zener diode TDb. The second Zener diode TDb protects the second charging capacitor Cb from damage due to overcharging.

(System control circuit 5)
As shown in FIG. 6, the inverter control circuit 2 that drives the inverter circuit 10, the first neutral line switching control circuit 3 that drives the first driving circuit 21, and the second neutral line switching that drives the second driving circuit 22. The control circuit 4 is connected to the system control circuit 5. The system control circuit 5 is composed of a microcomputer, and controls the inverter control circuit 2, the first neutral line switching control circuit 3, and the second neutral line switching control circuit 4 in an integrated manner.

  The system control circuit 5 drives the three-phase AC motor M with the winding structure as either the high-speed rotation winding HS or the low-speed rotation winding LS based on a command signal from an external device (not shown).

  That is, the system control circuit 5 causes the first infrared light emitting element D1a to emit light and does not cause the second infrared light emitting element D2a to emit light when the winding structure is the high-speed rotation winding HS and the three-phase AC motor M is driven. The first and second control signals CT1 and CT2 are output to the first and second neutral line switching control circuits 3 and 4, respectively.

  As a result, the first drive circuit 21 outputs a high-level first drive signal SD1, and the second drive circuit 22 outputs a low-level second drive signal SD2. Then, the switching elements Q1 to Q3 of the first switching circuit 11 are turned on, the switching elements Q4 to Q6 of the second switching circuit 12 are turned off, and the winding structure becomes the high-speed rotation winding HS.

  In this state, the system control circuit 5 also outputs a third control signal CT3 for supplying the three-phase AC power sources Vu, Vv, and Vw to each phase of the three-phase AC motor M to the inverter control circuit 2. To do.

  Thereby, the inverter control circuit 2 outputs the drive signals S1 to S6 to the gate terminals of the switching elements Qa to Qf. Based on the drive signals S1 to S6 from the inverter control circuit 2, the switching elements Qa to Qf are turned on / off at a predetermined timing, and the inverter circuit 10 applies the DC voltage Vdd of the DC power supply G to the three-phase AC power supply. It converts into Vu, Vv, Vw, and supplies it to each phase of the three-phase AC motor M.

  On the other hand, the system control circuit 5 causes the second infrared light emitting element D2a to emit light and does not cause the first infrared light emitting element D1a to emit light when the winding structure is the low speed rotating winding LS and the three-phase AC motor M is driven. The first and second control signals CT1 and CT2 are output to the first and second neutral line switching control circuits 3 and 4, respectively.

  As a result, the second drive circuit 22 outputs the high-level second drive signal SD2, and the first drive circuit 21 outputs the low-level first drive signal SD1. Then, the switching elements Q4 to Q6 of the second switching circuit 12 are turned on, the switching elements Q1 to Q3 of the first switching circuit 11 are turned off, and the winding structure becomes the low-speed rotation winding LS.

  In this state, the system control circuit 5 also outputs a third control signal CT3 for supplying the three-phase AC power sources Vu, Vv, and Vw to each phase of the three-phase AC motor M to the inverter control circuit 2. To do.

  Thereby, the inverter control circuit 2 outputs the drive signals S1 to S6 to the gate terminals of the switching elements Qa to Qf. Based on the drive signals S1 to S6 from the inverter control circuit 2, the switching elements Qa to Qf are turned on / off at a predetermined timing, and the inverter circuit 10 applies the DC voltage Vdd of the DC power supply G to the three-phase AC power supply. It converts into Vu, Vv, Vw, and supplies it to each phase of the three-phase AC motor M.

  The system control circuit 5 is connected to a rotation speed detector 6 that detects the rotation speed of the three-phase AC motor M, and receives a detection signal. The system control circuit 5 calculates the rotational speed of the three-phase AC motor M at that time based on the detection signal from the rotational speed detector 6. Then, when the rotational speed of the three-phase AC motor M is less than a predetermined rotational speed, the system control circuit 5 is configured so that the winding structure has a low rotational speed and a large torque with a low speed rotational winding LS. The phase AC motor M is driven and controlled. Further, the system control circuit 5 sets the winding structure to the high-speed rotation winding HS so that the high-speed rotation small torque is obtained when the rotation speed of the three-phase AC motor M is equal to or higher than a predetermined rotation speed. The phase AC motor M is driven and controlled.

(Charge mode)
In addition, the system control circuit 5 uses the first and second operation power supply circuits 31 and 3 before driving the three-phase AC motor M using the three-phase AC motor M as the high-speed rotation winding HS or the low-speed rotation winding LS. A pre-drive charging mode for charging the 32 first and second charging capacitors Ca and Cb is executed.

  That is, before driving the three-phase AC motor M, it is necessary to secure the operating power sources Vd1 and Vd2 of the first and second drive circuits 21 and 22 that drive the first and second switching circuits 11 and 12. Therefore, the charging operation for the first and second charging capacitors Ca and Cb of the first and second operation power supply circuits 31 and 32 is performed.

  When the system control circuit 5 enters the pre-drive charging mode, the first and second infrared light emission provided in the first and second drive circuits 21 and 22 with respect to the first and second neutral line switching control circuits 3 and 4. First and second control signals CT1 and CT2 that do not cause the elements D1a and D2a to emit light are output, respectively. As a result, a low-level first drive signal SD1 is output from the first drive circuit 21 to the first switching circuit 11, and the switching elements Q1 to Q3 of each phase of the first switching circuit 11 are turned off. Further, a low-level second drive signal SD2 is output from the second drive circuit 22 to the second switching circuit 12, and the switching elements Q4 to Q6 of each phase of the second switching circuit 12 are turned off.

Subsequently, the system control circuit 5 outputs to the inverter control circuit 2 a third control signal CT3 for turning on only the lower arm U-phase switching element Qb of the inverter circuit 10.
In response to the third control signal CT3, the inverter control circuit 2 outputs a high level drive signal S2 to the gate of the lower arm U-phase switching element Qb to turn on the switching element Qb.

  Accordingly, the DC power source G → the first resistor Ra → the first diode Da → the first charging capacitor Ca → the first neutral line NL1 → the body diode D of the first U-phase switching element Q1 → the first U-phase winding U1 → the lower arm. A current path from the U-phase switching element Qb to the ground is formed.

  At the same time, DC power supply G → second resistance Rb → second diode Db → second charging capacitor Cb → second neutral line NL2 → body diode D of second U-phase switching element Q4 → second U-phase winding U2 → second A current path of 1U phase winding U1 → lower arm U phase switching element Qb → ground is formed.

  Then, the charging of the first and second charging capacitors Ca and Cb of the first and second operation power supply circuits 31 and 32 is started. When the charging voltage (first and second operating voltages Vd1, Vd2) of the first and second charging capacitors Ca, Cb reaches a predetermined voltage value, the system control circuit 5 ends the charging mode, and the three-phase AC The driving mode for driving the electric motor M is started.

  The determination when the charging voltages of the first and second charging capacitors Ca and Cb reach a predetermined voltage value is, for example, a detection sensor that detects the charging voltages of the first and second charging capacitors Ca and Cb ( (Not shown). The system control circuit 5 receives a detection signal from the detection sensor, detects the charging voltage of the first and second charging capacitors Ca and Cb at that time based on the detection signal, and sets the predetermined voltage value. It may be possible to determine whether it has been reached.

Next, the operation of the winding switching device 1 of the three-phase AC motor M configured as described above will be described.
Now, a command signal is output from an external device to the system control circuit 5 in order to drive the three-phase AC motor M to a high-speed rotation small torque through a low-speed rotation large torque. The system control circuit 5 enters the pre-drive charge mode in which the first and second charging capacitors Ca and Cb of the first and second operation power supply circuits 31 and 32 are charged before entering the drive mode in response to the command signal. .

  The system control circuit 5 does not cause the first and second infrared light emitting elements D1a and D2a provided in the first and second drive circuits 21 and 22 to emit light to the first and second neutral line switching control circuits 3 and 4. First and second control signals CT1 and CT2 are output, respectively. As a result, a low-level first drive signal SD1 is output from the first drive circuit 21 to the first switching circuit 11, and the switching elements Q1 to Q3 of each phase of the first switching circuit 11 are turned off. Further, a low-level second drive signal SD2 is output from the second drive circuit 22 to the second switching circuit 12, and the switching elements Q4 to Q6 of each phase of the second switching circuit 12 are turned off.

  Subsequently, the system control circuit 5 turns on only the lower arm U-phase switching element Qb of the inverter circuit 10 and turns off the other switching elements Qa and Qc to Qf with respect to the inverter control circuit 2. Is output. In response to the third control signal CT3, the inverter control circuit 2 outputs a high level drive signal S2 to the gate of the lower arm U-phase switching element Qb to turn on the switching element Qb.

  DC power source G → first resistor Ra → first diode Da → first charging capacitor Ca → first neutral line NL1 → body diode D of the first U-phase switching element Q1 → first U-phase winding U1 → lower arm U A current path including the phase switching element Qb → ground is formed.

  At the same time, DC power supply G → second resistance Rb → second diode Db → second charging capacitor Cb → second neutral line NL2 → body diode D of second U-phase switching element Q4 → second U-phase winding U2 → second A current path composed of 1U-phase winding U1 → lower arm U-phase switching element Qb → ground is formed.

  As a result, charging of the first and second charging capacitors Ca and Cb of the first and second operation power supply circuits 31 and 32 is started. When the charging voltage (first and second operating voltages Vd1, Vd2) of the first and second charging capacitors Ca, Cb reaches a predetermined voltage value, the system control circuit 5 ends the charging mode, and the three-phase AC The driving mode for driving the electric motor M is started.

  Therefore, the first and second drive circuits 21 and 22 are applied with the charged voltages of the first and second charging capacitors Ca and Cb (first and second operating voltages Vd1 and Vd2) as operating voltages. The

  When the system control circuit 5 enters the drive mode, the first drive circuit 21 is provided with the first neutral circuit switching control circuit 3 in the first drive circuit 21 so as to drive the three-phase AC motor M with the low-speed rotation and large torque. The first control signal CT1 that does not cause the infrared light emitting element D1a to emit light is output. Then, the first drive circuit 21 outputs the low-level first drive signal SD1 to the first switching circuit 11 because the first infrared light emitting element D1a does not emit light, and the switching elements of the respective phases of the first switching circuit 11 Q1 to Q3 are turned off.

  Further, the system control circuit 5 outputs a second control signal CT2 that causes the second infrared light emitting element D2a provided in the second drive circuit 22 to emit light to the second neutral line switching control circuit 4. Then, the second drive circuit 22 outputs the high-level second drive signal SD2 to the second switching circuit 12 from the second infrared light emitting element D2a, and the switching element Q4 for each phase of the second switching circuit 12 is output. Turn on Q6.

As a result, the winding structure of the three-phase AC motor M becomes the low-speed rotation winding LS shown in FIG. 5, and the low-speed rotation large torque winding structure.
When the winding structure of the three-phase AC motor M is the low-speed rotation winding LS, the system control circuit 5 determines the 3 of each phase of the three-phase AC motor M from the DC voltage Vdd of the DC power supply G to the inverter control circuit 2. A third control signal CT3 for generating the phase AC power supplies Vu, Vv, Vw is output. In response to the third control signal CT3, the inverter control circuit 2 outputs drive signals S1 to S6 to the switching elements Qa to Qf of the inverter circuit 10, and controls the switching elements Qa to Qf on and off. Then, the inverter circuit 10 converts the DC voltage Vdd of the DC power supply G into a three-phase AC power supply Vu, Vv, Vw and supplies it to each phase of the three-phase AC motor M.

As a result, the three-phase AC motor M is driven by a low-speed rotation large torque winding structure (structure of the low-speed rotation winding LS).
When the three-phase AC motor M is driven by the winding structure of low-speed rotation and large torque, as shown in FIGS. 8A and 8B, the first neutral line voltage Va of the first neutral line NL1 is obtained. Is shown by the waveform c, and the second neutral line voltage Vb of the second neutral line NL2 is shown by the waveform d.

As is clear from FIGS. 8A and 8B, there is a region where the first neutral line voltage Va and the second neutral line voltage Vb are less than the DC voltage Vdd (= 12 V) of the DC power supply G.
As a result, in the second operating power supply circuit 32, a current path including the DC power supply G → the second resistor Rb → the second diode Db → the second charging capacitor Cb → the second neutral line NL2 is formed. By forming this current path, the second charging capacitor Cb is charged to the second operating voltage Vd2 with the DC voltage Vdd (= 12V) of the DC power supply G.

  Eventually, when the system control circuit 5 determines that the rotational speed of the three-phase AC motor M has reached a predetermined rotational speed or more based on the detection signal from the rotational speed detector 6, the system control circuit 5 is driven with a low-speed rotational large torque. The three-phase AC motor M is switched to drive at high speed and small torque.

  Then, the system control circuit 5 includes a first infrared light emitting element D1a provided in the first drive circuit 21 with respect to the first neutral line switching control circuit 3 so as to drive the three-phase AC motor M with high-speed rotation and small torque. The first control signal CT1 for emitting light is output. Then, the first drive circuit 21 outputs the high-level first drive signal SD1 to the first switching circuit 11 from the first infrared light emitting element D1a, and the switching element Q1 for each phase of the first switching circuit 11 is output. Turn on ~ Q3.

  Further, the system control circuit 5 outputs a second control signal CT2 that does not cause the second infrared light emitting element D2a provided in the second drive circuit 22 to emit light to the second neutral line switching control circuit 4. Then, the second drive circuit 22 outputs the low-level second drive signal SD2 to the second switching circuit 12 because the second infrared light emitting element D2a does not emit light, and the switching elements of the respective phases of the second switching circuit 12 Q4 to Q6 are turned off.

As a result, the winding structure of the three-phase AC motor M becomes the high-speed rotation winding HS shown in FIG. 4, and the high-speed rotation small torque winding structure.
When the winding structure of the three-phase AC motor M is a high-speed rotation winding HS, the system control circuit 5 sends the inverter control circuit 2 3 of each phase of the three-phase AC motor M from the DC voltage Vdd of the DC power supply G. A third control signal CT3 for generating the phase AC power supplies Vu, Vv, Vw is output. In response to the third control signal CT3, the inverter control circuit 2 outputs drive signals S1 to S6 to the switching elements Qa to Qf of the inverter circuit 10, and controls the switching elements Qa to Qf on and off. Then, the inverter circuit 10 converts the DC voltage Vdd of the DC power supply G into a three-phase AC power supply Vu, Vv, Vw and supplies it to each phase of the three-phase AC motor M.

As a result, the three-phase AC motor M is driven with a winding structure of high-speed rotation and small torque (structure of the high-speed rotation winding HS).
When the three-phase AC motor M is driven by the winding structure of high-speed rotation and small torque, as shown in FIGS. 7A and 7B, the first neutral line voltage Va of the first neutral line NL1. Is shown by the waveform a, and the second neutral line voltage Vb of the second neutral line NL2 is shown by the waveform b.

As is apparent from FIGS. 7A and 7B, there is a region where the first neutral line voltage Va and the second neutral line voltage Vb are less than the DC voltage Vdd (= 12 V) of the DC power supply G.
As a result, in the first operating power supply circuit 31, a current path consisting of the DC power supply G → the first resistor Ra → the first diode Da → the first charging capacitor Ca → the first neutral line NL1 is formed. By forming the formed current path, the first charging capacitor Ca is charged to the first operating voltage Vd1 with the DC voltage Vdd (= 12V) of the DC power supply G.

  When the system control circuit 5 determines that the rotational speed of the three-phase AC motor M is less than the predetermined rotational speed based on the detection signal from the rotational speed detector 6, the system control circuit 5 drives the motor with high rotational speed and small torque. The three-phase AC motor M is switched to drive at low speed and large torque. As described above, the first and second switching circuits 11 and 12 are controlled, and the three-phase AC motor M is driven by the winding structure of the low-speed rotation and large torque (structure of the low-speed rotation winding LS). .

  The second operating power supply circuit 32 is formed with a current path composed of a DC power supply G → second resistor Rb → second diode Db → second charging capacitor Cb → second neutral line NL2. It is charged with the DC voltage Vdd (= 12V) of the power supply G.

  Furthermore, by simultaneously turning on the switching elements Qb, Qd, Qf of the lower arms of all three phases of the inverter circuit 10, the voltages at the neutral points NL1, NL2 can be further lowered. By repeating this operation intermittently, a stable operation is possible, and the same effect as the bootstrap system can be obtained.

Next, the effect of the winding switching device 1 of the three-phase AC motor M configured as described above will be described below.
(1) According to this embodiment, in the first operating power supply circuit 31, the anode terminal of the first diode Da is connected to the positive terminal of the DC power supply G via the first resistor Ra, and the cathode of the first diode Da. The terminal was connected to the first neutral line NL1 via the first charging capacitor Ca.

  Then, a current path including a DC power supply G → first resistor Ra → first diode Da → first charging capacitor Ca → first neutral line NL1 is formed, and the first driving circuit 21 has a first path in the first charging capacitor Ca. The charging voltage that is the operating voltage Vd1 is charged.

  Therefore, the first operation power supply circuit 31 can realize the power supply circuit of the first drive circuit 21 with a very simple circuit configuration including the first resistor Ra, the first diode Da, and the first charging capacitor Ca.

  On the other hand, in the second operating power supply circuit 32, the anode terminal of the second diode Db is connected to the plus terminal of the DC power supply G via the second resistor Rb, and the cathode terminal of the second diode Db is connected to the second charging capacitor Cb. To the second neutral line NL2.

  Then, a current path consisting of DC power supply G → second resistor Rb → second diode Db → second charging capacitor Cb → second neutral line NL2 is formed, and the second charging capacitor Cb has a second drive circuit 22 second current. The charging voltage that is the operating voltage Vd2 is charged.

  Therefore, the second operation power supply circuit 32 can realize the power supply circuit of the second drive circuit 22 with a very simple circuit configuration of the second resistor Rb, the second diode Db, and the second charging capacitor Cb.

(2) According to the present embodiment, before driving the three-phase AC motor M, only the lower arm U-phase switching element Qb of the inverter circuit 10 is turned on.
For the first operating power supply circuit 31, the DC power supply G → the first operating power supply circuit 31 → the first neutral line NL1 → the body diode D of the first U-phase switching element Q1 → the first U-phase winding U1 → the lower arm U A current path composed of the phase switching element Qb → ground was formed.

  Further, for the second operating power supply circuit 32, the DC power supply G → the second operating power supply circuit 32 → the second neutral line NL2 → the body diode D of the second U-phase switching element Q4 → the second U-phase winding U2 → the first U-phase. A current path consisting of winding U1 → lower arm U-phase switching element Qb → ground was formed.

  Therefore, the first and second charging capacitors Ca and Cb are charged before driving. As a result, the first and second operating voltages Vd1, Vd2 of the first and second drive circuits 21, 22 are ensured before driving, and the three-phase AC motor M can be driven more stably.

  (3) According to the present embodiment, the first and second Zener diodes TDa and TDb are connected in parallel to the first and second charging capacitors Ca and Cb, respectively. Therefore, even if an overvoltage is applied to the first and second charging capacitors Ca and Cb, the first and second Zener diodes TDa and TDb absorb this, and damage due to the overvoltage of the first and second charging capacitors Ca and Cb is prevented. It can be prevented beforehand.

The first embodiment may be modified as follows.
In the above embodiment, before driving the three-phase AC motor M, only the lower arm U-phase switching element Qb of the inverter circuit 10 is turned on to charge the first and second charging capacitors Ca and Cb. did. This may be performed by turning on the lower arm V-phase switching element Qb and the lower arm W-phase switching element Qf of the inverter circuit 10 and charging the first and second charging capacitors Ca and Cb. Good. As a result, the charging operation can be completed more quickly.

  In the above embodiment, the first and second operation power supply circuits 31 and 32 are directly connected to the DC power supply G. However, when the DC voltage Vdd of the DC power supply G is low, as shown in FIG. 40 is provided. Then, the DC voltage Vdd of the DC power supply G may be boosted by the booster circuit 40 and the boosted boosted voltage may be applied to the first and second operation power supply circuits 31 and 32.

As a result, even when the DC voltage Vdd of the DC power supply G is low, a stable charging voltage can be supplied to the first and second drive circuits 21 and 22.
In the above embodiment, the charging voltages of the first and second charging capacitors Ca and Cb of the first and second operating power supply circuits 31 and 32 are set as the first and second operating voltages Vd1 and Vd2, respectively. 2 was supplied directly to the drive circuits 21 and 22. As shown in FIG. 10, a zener diode TDx, a resistor Rx, and a bipolar transistor Qx1 for a current booster are provided between the first and second charging capacitors Ca, Cb and the first and second drive circuits 21, 22. The first and second constant voltage circuits 41 and 42 may be provided.

In this case, stable first and second operating voltages Vd1 and Vd2 can be supplied to the first and second drive circuits 21 and 22.
Further, as shown in FIG. 11, between the first and second charging capacitors Ca and Cb and the first and second drive circuits 21 and 22, an inductor Lx, a check diode Dx, a boost MOS transistor Qx2, a charge For example, the first and second booster circuits 43 and 44 including the capacitor Cx may be provided.

  In this case, even when the charging voltages of the first and second charging capacitors Ca and Cb are low, a high voltage is stably generated, and the high voltage is supplied to the first and second drive circuits 21 and 22 in the first and The second operating voltages Vd1 and Vd2 can be supplied.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The present embodiment is different from the first embodiment in that a failure of each switching element Q1 to Q6 is detected in the first and second switching circuits 11 and 12 provided in the winding switching device 1 of the first embodiment. Therefore, for the sake of convenience of explanation, portions common to the first embodiment are omitted, and feature portions will be described in detail.

  As shown in FIG. 12, a pull-up resistor Rpu is connected between the power receiving terminals Tu, Tv, Tw of each phase and the positive terminal of the DC power supply G, and the power receiving terminals Tu, Tv of each phase. , Tw and ground are respectively connected to pull-down resistors Rpd. Both the pull-up resistor Rpu and the pull-down resistor Rpd are set to the same resistance value.

  The first neutral line NL1 is connected to the ground via the first voltage detection resistor Rz1, and the second neutral line NL2 is connected to the ground via the second voltage detection resistor Rz2. . Both the first voltage detection resistor Rz1 and the second voltage detection resistor Rz2 are set to the same resistance value.

  As shown in FIG. 13, the system control circuit 5 includes a U-phase power receiving terminal voltage detection circuit 51 that detects the terminal voltages of the power receiving terminals Tu, Tv, and Tw of each phase by using the voltage between the terminals of the pull-down resistor Rpd. A power receiving terminal voltage detection circuit 52 and a W-phase power receiving terminal voltage detection circuit 53 are connected. The system control circuit 5 calculates the terminal voltage of the power receiving terminal Tu based on the detection signal from the U-phase power receiving terminal voltage detection circuit 51. Further, the system control circuit 5 calculates the terminal voltage of the power receiving terminal Tv based on the detection signal from the V-phase power receiving terminal voltage detection circuit 52. Further, the system control circuit 5 calculates the terminal voltage of the power receiving terminal Tw based on the detection signal from the W-phase power receiving terminal voltage detection circuit 53.

  The system control circuit 5 uses the first and second neutral line voltages Va and Vb of the first and second neutral lines NL1 and NL2 as voltages between the terminals of the first and second voltage detection resistors Rz1 and Rz2, respectively. A first neutral line voltage detection circuit 54 and a second neutral line voltage detection circuit 55 to be detected are connected. Then, the system control circuit 5 calculates the first neutral line voltage Va based on the detection signal from the first neutral line voltage detection circuit 54. Further, the system control circuit 5 calculates the second neutral line voltage Vb based on the detection signal from the second neutral line voltage detection circuit 55.

  The system control circuit 5 receives a command signal for short circuit failure detection or open failure detection from an external device (not shown). The system control circuit 5 enters a short failure detection mode when a command signal for short failure detection is input from an external device. Further, when a command signal for detecting an open failure is input from an external device, the system control circuit 5 enters an open failure detection mode.

  Here, the short circuit failure means that the switching elements Q1 to Q6 made of N-channel MOS transistors output the low level first and second drive signals SD1 and SD2 respectively, but the switching elements It means being on.

  In addition, an open failure means that the switching elements are turned off in spite of the high-level first and second drive signals SD1 and SD2 being output from the switching elements Q1 to Q6 made of N-channel MOS transistors. It means being in a state.

  Note that the winding switching device 1 of the present embodiment connects the pull-up resistor Rpu and the pull-down resistor Rpd to the power receiving terminals Tu, Tv, Tw, respectively, and the first and second neutral lines NL1, NL2, respectively. The second voltage detection resistors Rz1 and Rz2 are connected.

  With the circuit configuration in which the pull-up resistor Rpu, the pull-down resistor Rpd, and the first and second voltage detection resistors Rz1 and Rz2 are added, the winding structure is a high-speed rotation HS and a low-speed rotation as in the first embodiment. It goes without saying that the three-phase AC motor M can be driven by switching to the winding LS. Of course, the first and second charging capacitors Ca and Cb of the first and second operation power supply circuits 31 and 32 can be charged in the same manner as in the first embodiment.

Next, the operation of the winding switching device 1 configured as described above will be described according to the failure detection processing operation of the system control circuit 5.
(Short failure detection mode)
When a command signal for detecting a short fault is input to the system control circuit 5 from an external device (not shown), the system control circuit 5 enters a short fault detection mode and executes a short fault detection processing operation.

  First, the system control circuit 5 turns off all the switching elements Qa to Qf of the inverter circuit 10 in order to execute the short fault detection processing operation of the switching elements Q1 to Q6 of the first and second switching circuits 11 and 12. To output to the inverter control circuit 2 a third control signal CT3. As a result, all the switching elements Qa to Qf of the inverter circuit 10 are turned off, and the terminal voltage of each of the power receiving terminals Tu, Tv, and Tw is a voltage (intermediate voltage) that is ½ of the DC voltage Vdd of the DC power supply G. Become.

  In addition, the system control circuit 5 outputs first and second neutralization signals CT1 and CT2 for turning off the switching elements Q1 to Q6 of the first and second switching circuits 11 and 12, respectively. Output to the line switching control circuits 3 and 4 respectively. Accordingly, the switching elements Q1 to Q6 of the first and second switching circuits 11 and 12 output the low-level first and second driving signals SD1 and SD2 from the first and second driving circuits 21 and 22, respectively. Turns off.

  At this time, if the switching elements Q1 to Q6 of the first and second switching circuits 11 and 12 are normal, the first neutral line voltage Va and the second neutral line voltage Vb are low voltages (almost 0V). . Further, the terminal voltages of the power receiving terminals Tu, Tv, and Tw are intermediate voltages. When the first and second neutral line voltages Va and Vb are low, the system control circuit 5 determines that the switching elements Q1 to Q6 of the first and second switching circuits 11 and 12 are normal without any short-circuit failure. to decide.

  Here, when one of the first neutral line voltage Va and the second neutral line voltage Vb is an intermediate voltage and the other is a low voltage, the switching circuit on the side that has become the intermediate voltage It is determined that there is a short-circuited switching element.

  For example, when the first neutral line voltage Va is an intermediate voltage and the second neutral line voltage Vb is a low voltage, one of the switching elements Q1 to Q3 in the first switching circuit 11 is short-circuited. Judge that

  On the contrary, when the second neutral line voltage Vb is an intermediate voltage and the first neutral line voltage Va is a low voltage, one of the switching elements Q4 to Q6 in the second switching circuit 12 is short-circuited. Judge that you are doing.

  Then, the system control circuit 5 determines which phase of the switching elements Q1 to Q3 of the first switching circuit 11 is short-circuited or the switching elements Q4 to Q6 of the second switching circuit 12. A process for identifying which phase of the switching element has a short circuit failure is performed.

  First, the system control circuit 5 outputs to the inverter control circuit 2 a third control signal CT3 for turning on only the upper arm U-phase switching element Qa among the switching elements Qa to Qf of the inverter circuit 10. Thus, inverter control circuit 2 turns on only upper arm U-phase switching element Qa among all switching elements Qa to Qf of inverter circuit 10.

  At this time, for example, when the first U-phase switching element Q1 of the first switching circuit 11 is short-circuited, the first neutral line voltage Va becomes a high voltage that is substantially close to the DC voltage Vdd, and the second neutral voltage The line voltage Vb becomes a low voltage. Then, when the first neutral line voltage Va becomes a high voltage, it is determined that the first U-phase switching element Q1 is short-circuited.

  Incidentally, when the first U-phase switching element Q1 is short-circuited and only the upper arm V-phase switching element Qc is turned on, or when only the upper arm W-phase switching element Qe is turned on. The first neutral line voltage Va becomes an intermediate voltage, and the second neutral line voltage Vb becomes a low voltage.

  Therefore, when the first V-phase switching element Q2 of the first switching circuit 11 is short-circuited, the first neutral line voltage Va is a high voltage when only the upper arm V-phase switching element Qc is turned on. Thus, it can be determined that the first V-phase switching element Q2 is short-circuited when the second neutral line voltage Vb becomes a low voltage.

  When the first W-phase switching element Q3 of the eleventh switching circuit 11 is short-circuited, the first neutral line voltage Va is a high voltage when only the upper arm W-phase switching element Qe is turned on. Thus, when the second neutral line voltage Vb becomes a low voltage, it can be determined that the first W-phase switching element Q3 is short-circuited.

  On the other hand, when the second U-phase switching element Q4 of the second switching circuit 12 is short-circuited, the second neutral line voltage Vb is a high voltage when only the upper arm U-phase switching element Qa is turned on. Thus, when the first neutral line voltage Va becomes a low voltage, it can be determined that the second U-phase switching element Q4 is short-circuited.

  Further, when the second V-phase switching element Q5 of the second switching circuit 12 is short-circuited, the second neutral line voltage Vb is a high voltage when only the upper arm V-phase switching element Qc is turned on. Thus, when the first neutral line voltage Va becomes low, it can be determined that the second V-phase switching element Q5 is short-circuited.

  Further, when the second W-phase switching element Q6 of the second switching circuit 12 is short-circuited, the second neutral line voltage Vb is high when only the upper arm W-phase switching element Qe is turned on. Thus, when the first neutral line voltage Va becomes low, it can be determined that the second W-phase switching element Q6 has a short circuit failure.

  Therefore, after determining that the first switching circuit 11 is short-circuited, the system control circuit 5 turns on only one of the switching elements Qa, Qc, and Qe of the upper arm. Then, it is specified that the switching elements Q1 to Q3 of the phase corresponding to the switching elements Qa, Qc, and Qe that are in the on state when the first neutral line voltage Va is high are in short circuit failure. Can do.

  Further, after determining that the second switching circuit 12 is short-circuited, the system control circuit 5 turns on only one of the upper arm switching elements Qa, Qc, and Qe. Then, it is specified that the switching elements Q4 to Q6 of the phase corresponding to the switching elements Qa, Qc, and Qe that are in the on state when the second neutral line voltage Vb is a high voltage have a short circuit failure. Can do.

  In this embodiment, first, all the switching elements Qa to Qf of the inverter circuit 10 are turned off, there is no short circuit failure, and if there is, the first switching circuit 11 or the second switching circuit 11 Although it has been determined whether or not it is the switching circuit 12, this may be omitted.

  That is, only one of the upper arm switching elements Qa, Qc, and Qe is sequentially turned on. If only one of the switching elements Q1 to Q6 of the first and second switching circuits 11 and 12 is normal when only one of them is turned on, the first neutral line voltage Va and the second neutral line voltage Vb. Becomes a low voltage.

  At this time, when the first neutral line voltage Va is high and the second neutral line voltage Vb is low, the switching element Qa in the first switching circuit 11 is turned on. It can be specified that the switching elements Q1 to Q3 of the phases corresponding to Qc and Qe are short-circuited. When the first neutral line voltage Va is a high voltage and the second neutral line voltage Vb is a low voltage, the switching elements Qa, Qc, Qe which are the first switching circuit 11 and are in the ON state. It can be determined that any one of the switching elements Q1 to Q3 other than the phase corresponding to 1 is short-circuited.

  On the other hand, at this time, when the second neutral line voltage Vb is a high voltage and the first neutral line voltage Va is a low voltage, the switching element Qa in the second switching circuit 12 is turned on. , Qc, Qe, it can be specified that the switching elements Q4 to Q6 of the phase corresponding to the short-circuit failure. Similarly, when the second neutral line voltage Vb is a high voltage and the first neutral line voltage Va is a low voltage, the switching elements Qa, Qc, It can be determined that any of the switching elements Q4 to Q6 other than the phase corresponding to Qe has a short circuit failure.

  When the switching elements Q1 to Q6 are not short-circuited, the system control circuit 5 outputs a message to that effect to the external device. Further, when the system control circuit 5 detects a short-circuit failure, the system control circuit 5 outputs the data of the switching element of the identified short-circuit failure phase to an external device.

  And when the switching element of the 1st or 2nd switching circuit 11 and 12 carries out a short circuit failure, the emergency operation can be carried out according to the 1st or 2nd switching circuit 11 and 12 which the three-phase AC motor M failed. .

  That is, when one of the switching elements Q1 to Q6 of the first or second switching circuit 11 or 12 is short-circuited, the system control circuit 5 sets the switching circuit on the short-circuited side to the energized side, and sets a normal switching circuit. By de-energizing, the three-phase AC motor M can be actuated quickly.

(Open failure detection processing operation)
If a command signal for detecting an open failure is input to the system control circuit 5 from an external device (not shown), the system control circuit 5 enters an open failure detection mode and executes an open failure detection processing operation.

The system control circuit 5 first executes an open failure detection processing operation for each of the switching elements Q1 to Q3 of the first switching circuit 11.
First, the system control circuit 5 outputs a first control signal CT1 for turning on the switching elements Q1 to Q3 of the first switching circuit 11 to the first neutral line switching control circuit 3. Accordingly, the switching elements Q1 to Q3 of the first switching circuit 11 are turned on when the first driving signal SD1 of the high level is output from the first driving circuit 21.

  At this time, the system control circuit 5 outputs a second control signal CT2 for turning off the switching elements Q4 to Q6 of the second switching circuit 12 to the second neutral line switching control circuit 4. Accordingly, the switching elements Q4 to Q6 of the second switching circuit 12 are turned off when the second driving circuit 22 outputs the low-level second driving signal SD2.

  Next, the third control signal CT3 for turning on only the switching element Qa among all the switching elements Qa to Qf of the inverter circuit 10 is output to the inverter control circuit 2. Thereby, only the switching element Qa of the inverter circuit 10 is turned on.

  Here, since the first U-phase switching element Q1 is in the on state when it is normal, the first neutral line voltage Va becomes a high voltage. On the other hand, since the first U-phase switching element Q1 is turned off when an open failure occurs, the first neutral line voltage Va is equal to or lower than the intermediate voltage (the switching element Q2, Q3 is low when the open failure occurs). Voltage).

  When the first U-phase switching element Q1 is an open failure and the other switching elements Q2 and Q3 are normal, the first switching element Qc of the inverter circuit 10 or only the switching element Qe is turned on. The neutral line voltage Va is a high voltage, and the second neutral line voltage Vb is a low voltage.

  Therefore, if the system control circuit 5 obtains the voltage value of the first neutral line voltage Va at that time based on the detection signal from the first neutral line voltage detection circuit 54, the open fault of the first U-phase switching element Q1 The presence or absence of can be detected.

  Further, the third control signal CT3 for turning on only the switching element Qc among all the switching elements Qa to Qf of the inverter circuit 10 is output to the inverter control circuit 2. Thereby, only the switching element Qc of the inverter circuit 10 is turned on.

  At this time, since the first V-phase switching element Q2 is in the on state when it is normal, the first neutral line voltage Va becomes a high voltage. On the other hand, since the first V-phase switching element Q2 is turned off when an open failure occurs, the first neutral line voltage Va is equal to or lower than the intermediate voltage (the switching element Q1, Q3 is low when the open failure occurs). Voltage).

  When the first V-phase switching element Q2 is an open failure and the other switching elements Q1 and Q3 are normal, only the switching element Qa of the inverter circuit 10 or only the switching element Qe is turned on. The neutral line voltage Va is a high voltage, and the second neutral line voltage Vb is a low voltage.

  Therefore, if the system control circuit 5 obtains the voltage value of the first neutral line voltage Va at that time based on the detection signal from the first neutral line voltage detection circuit 54, the open fault of the first V-phase switching element Q2 The presence or absence of can be detected.

  Further, the third control signal CT3 for turning on only the switching element Qe among all the switching elements Qa to Qf of the inverter circuit 10 is output to the inverter control circuit 2. As a result, only the switching element Qe of the inverter circuit 10 is turned on.

  At this time, since the first W-phase switching element Q3 is in the on state when it is normal, the first neutral line voltage Va becomes a high voltage. On the contrary, since the first W-phase switching element Q3 is turned off when an open failure occurs, the first neutral line voltage Va is equal to or lower than the intermediate voltage (the switching element Q1, Q2 is low when the open failure occurs). Voltage).

  When the first W-phase switching element Q3 is open and the other switching elements Q1 and Q2 are normal, the first switching element Qa or only the switching element Qc of the inverter circuit 10 is turned on. The neutral line voltage Va is a high voltage, and the second neutral line voltage Vb is a low voltage.

  Therefore, if the system control circuit 5 obtains the voltage value of the first neutral line voltage Va at that time based on the detection signal from the first neutral line voltage detection circuit 54, the open failure of the first W-phase switching element Q3 The presence or absence of can be detected.

Next, the system control circuit 5 executes an open failure detection processing operation for each of the switching elements Q4 to Q6 of the second switching circuit 12.
The system control circuit 5 outputs a second control signal CT2 for turning on the switching elements Q4 to Q6 of the second switching circuit 12 to the first neutral line switching control circuit 3. As a result, the switching elements Q4 to Q6 of the second switching circuit 12 are turned on when the first driving signal SD1 at the high level is output from the second driving circuit 22.

  At this time, the system control circuit 5 outputs a first control signal CT1 for turning off the switching elements Q1 to Q3 of the first switching circuit 11 to the first neutral line switching control circuit 3. As a result, the switching elements Q1 to Q3 of the first switching circuit 11 are turned off when the low-level second driving signal SD2 is output from the first driving circuit 21.

  Next, similarly to the above, the system control circuit 5 outputs the third control signal CT3 for turning on only the switching element Qa among the switching elements Qa to Qf to the inverter control circuit 2, and the inverter circuit 10 Only the switching element Qa is turned on.

  Here, since the second U-phase switching element Q4 is in the on state when it is normal, the second neutral line voltage Vb becomes a high voltage. On the other hand, when the second U-phase switching element Q4 has an open failure, it is turned off, so the second neutral voltage Vb is equal to or lower than the intermediate voltage (if the switching elements Q5 and Q6 also have an open failure, it is low. Voltage).

  When the second U-phase switching element Q4 has an open failure and the other switching elements Q5 and Q6 are normal, when the switching element Qc of the inverter circuit 10 or only the switching element Qe is turned on, the second The neutral line voltage Vb is a high voltage, and the first neutral line voltage Va is a low voltage.

  Therefore, if the system control circuit 5 obtains the voltage value of the second neutral line voltage Vb at that time based on the detection signal from the second neutral line voltage detection circuit 55, the open fault of the second U-phase switching element Q4 The presence or absence of can be detected.

  Further, the system control circuit 5 outputs a third control signal CT3 for turning on only the switching element Qc among the switching elements Qa to Qf to the inverter control circuit 2, and only the switching element Qc of the inverter circuit 10 is output. Turn on.

  At this time, since the second V-phase switching element Q5 is in the on state when it is normal, the second neutral line voltage Vb becomes a high voltage. On the contrary, since the second V-phase switching element Q5 is turned off when an open failure occurs, the second neutral line voltage Vb is equal to or lower than the intermediate voltage (the switching element Q4, Q6 is low when the open failure occurs). Voltage).

  When the second V-phase switching element Q5 has an open failure and the other switching elements Q4 and Q6 are normal, when the switching element Qa of the inverter circuit 10 alone or only the switching element Qe is turned on, the second The neutral line voltage Vb is a high voltage, and the first neutral line voltage Va is a low voltage.

  Therefore, if the system control circuit 5 obtains the voltage value of the second neutral line voltage Vb at that time based on the detection signal from the second neutral line voltage detection circuit 55, the open fault of the second V-phase switching element Q5. The presence or absence of can be detected.

  Further, the system control circuit 5 outputs a third control signal CT3 for turning on only the switching element Qe among the switching elements Qa to Qf to the inverter control circuit 2, and only the switching element Qe of the inverter circuit 10 is output. Turn on.

  At this time, since the second W-phase switching element Q6 is in the on state when it is normal, the second neutral line voltage Vb becomes a high voltage. On the other hand, since the second W-phase switching element Q6 is turned off when an open failure occurs, the second neutral line voltage Vb is equal to or lower than the intermediate voltage (the switching element Q4, Q5 is low when the open failure occurs). Voltage).

  When the second W-phase switching element Q6 is an open failure and the other switching elements Q4 and Q5 are normal, when the switching element Qa of the inverter circuit 10 alone or only the switching element Qc is turned on, the second The neutral line voltage Vb is a high voltage, and the first neutral line voltage Va is a low voltage.

  Therefore, if the system control circuit 5 obtains the voltage value of the second neutral line voltage Vb at that time based on the detection signal from the second neutral line voltage detection circuit 55, the open failure of the first W-phase switching element Q3 The presence or absence of can be detected.

  When the switching elements Q1 to Q6 do not have an open failure, the system control circuit 5 outputs a message to that effect to the external device. Further, when the system control circuit 5 detects an open failure, the system control circuit 5 outputs data of the switching element having the open failure to an external device.

  And when the switching element of the 1st or 2nd switching circuit 11 and 12 has an open failure, the three-phase AC motor M can perform an emergency operation according to the failed 1st or 2nd switching circuit 11 and 12. .

  That is, when the switching elements Q1 to Q6 of the first or second switching circuits 11 and 12 have an open failure, the system control circuit 5 sets the switching circuit on the open failure side to the non-energized side and energizes the normal switching circuit. Thus, the three-phase AC electric motor M can be operated quickly.

Next, the effect of the winding switching device 1 configured as described above will be described below.
(1) According to the present embodiment, the three-phase AC motor M is provided in the first and second switching circuits 11 and 12 for switching the winding structure between the high-speed rotation winding HS and the low-speed rotation winding LS. Short faults and open faults of the switching elements Q1 to Q6 can be detected.

  As a result, when the switching element of the first or second switching circuit 11 or 12 is short-circuited or opened, the three-phase AC motor M is activated according to the first or second switching circuit 11 or 12 that has failed. can do.

  That is, when the switching element is short-circuited, the three-phase AC motor M can be operated quickly by setting the switching circuit on the short circuit side to the energizing side and de-energizing the normal switching circuit.

  Further, when the switching element has an open failure, the three-phase AC motor M can be operated in an emergency by setting the switching circuit on the open failure side to the non-energized side and energizing the normal switching circuit.

  (2) According to the present embodiment, all the switching elements Qa to Qf of the inverter circuit 10 are controlled to be turned off so that the switching elements Q1 to Q6 are turned off. Then, only by detecting the first neutral line voltage Va (second neutral line voltage Vb) at that time, it is possible to detect whether or not any of the switching elements Q1 to Q6 is short-circuited.

  In addition, when any of the switching elements Q1 to Q6 is short-circuited, the switching elements Qa, Qc, and Qe of the upper arm among the switching elements Qa to Qf of the inverter circuit 10 are sequentially turned on. Then, only by detecting the first neutral line voltage Va (second neutral line voltage Vb) at that time, it is possible to detect which of the switching elements Q1 to Q6 has a short circuit failure.

  (3) According to the present embodiment, the switching elements Q4 to Q6 of the second switching circuit 12 are turned off. Then, the switching elements Q1 to Q3 of the first switching circuit 11 are turned on, and the switching elements Qa, Qc, and Qe of the upper arm among the switching elements Qa to Qf of the inverter circuit 10 are sequentially turned on. Then, by detecting only the first neutral line voltage Va at that time, it is possible to detect which switching element among the switching elements Q1 to Q3 has an open failure.

  Further, the switching elements Q1 to Q3 of the first switching circuit 11 are turned off. Then, the switching elements Q4 to Q6 of the second switching circuit 12 are turned on, and the switching elements Qa, Qc, and Qe of the upper arm among the switching elements Qa to Qf of the inverter circuit 10 are sequentially turned on. Then, only by detecting the second neutral line voltage Vb at that time, it is possible to detect which of the switching elements Q4 to Q6 has an open failure.

  (4) According to the present embodiment, the series circuit including the pull-up resistor Rpu and the pull-down resistor Rpd connected to the power receiving terminals Tu, Tv, Tw of each phase, the first and second neutral lines NL1, NL2, A short circuit failure and an open failure can be detected with a simple circuit configuration including the first and second voltage detection resistors connected between the grounds.

  DESCRIPTION OF SYMBOLS 1 ... Winding switching apparatus, 2 ... Inverter control circuit, 3 ... 1st neutral wire switching control circuit, 4 ... 2nd neutral wire switching circuit, 5 ... System control circuit, 6 ... Speed detector, 10 ... Inverter Circuit 11 11 First switching circuit 12 Second switching circuit 21 First driving circuit 21 a First amplifier 21 b First logic circuit 22 Second driving circuit 22 a Second amplifier 22 b 2nd logic circuit, 31 ... 1st operation power supply circuit, 32 ... 2nd operation power supply circuit, 40 ... Booster circuit (DC voltage booster circuit), 41, 42 ... 1st and 2nd constant voltage circuit (constant voltage circuit) , 43, 44... First and second booster circuits (operating voltage booster circuit), 51... U phase power receiving terminal voltage detection circuit, 52... V phase power receiving terminal voltage detection circuit, 53. ... 1st neutral wire voltage detection circuit, 55 ... 2nd neutral wire voltage detection circuit, M 3-phase AC motor, G ... DC power supply, D ... body diode, U1 ... first U-phase winding, U2 ... second U-phase winding, V1 ... first V-phase winding, V2 ... second V-phase winding, W1 ... first 1W-phase winding, W2 ... 2nd W-phase winding, U1a, U2a, V1a, V2a, W1a, W2a ... drawer start end, U1b, U2b, V1b, V2b, W1b, W2b ... drawer termination, Tu, Tv, Tw ... Receiving terminal, Tu1, Tv1, Tw1 ... Connection terminal (connection part, first neutral wire terminal), Tu2, Tv2, Tw2 ... External terminal (second neutral wire terminal), Qa ... Upper arm U-phase switching Element (upper arm switching element), Qb ... Lower arm U phase switching element (lower arm switching element), Qc ... Upper arm V phase switching element (upper arm switching element), Qd ... Lower arm V phase switching element Lower arm switching element), Qe ... Upper arm W phase switching element (upper arm switching element), Qf ... Lower arm W phase switching element (lower arm switching element), Q1 ... First U phase switching element (first switching switching element) , Q2 ... first V-phase switching element (first switching switching element), Q3 ... first W-phase switching element (first switching switching element), Q4 ... second U-phase switching element (second switching switching element), Q5 ... second V Phase switching element (second switching switching element), Q6 ... 2nd W phase switching element (second switching switching element), R1 to R9, R11 to R19 ... resistance, D1 to D6 ... diode, TD1 to TD6 ... Zener diode, NL1 , NL2 ... first and second neutral wires, HS ... winding for high-speed rotation LS ... winding for low speed rotation, Ca, Cb ... first and second charging capacitors, Ra, Rb ... first and second resistors, Da, Db ... first and second diodes, TDa, TDb ... first and Second Zener Diode, Tp1, Tp2 ... Plus Terminal, Tn1, Tn2 ... Minus Terminal, S1-S6 ... Drive Signal, SD1, SD2 ... First and Second Drive Signals, CT1-CT3 ... First to Third Control Signals, Vdd ... DC voltage, Vd1 ... first operating voltage, Vd2 ... second operating voltage, Vu, Vv, Vw ... 3-phase AC power supply, Q1-Q6 ... MOS transistor, Q11 ... first MOS transistor, Q12 ... second MOS transistor, Rpu ... Pull-up resistor, Rpd ... Pull-down resistor, Rz1, Rz2 ... First and second voltage detection resistors, N1, N2, N3, N4, N5, N6, Na, Nb, Nc ... Connection point.

Claims (11)

Each phase winding is composed of a first winding and a second winding, a power receiving terminal is provided at the leading end of the first winding, a leading end of the first winding, and a leading start of the second winding. A three-phase AC motor provided with a first neutral wire terminal at the connecting portion and a second neutral wire terminal at the leading end portion of the second winding;
A three-phase inverter circuit that inputs a DC voltage of a DC power source, converts the DC voltage into a three-phase AC power source, and applies the three-phase AC power source to a power receiving terminal of a corresponding phase of the three-phase AC motor;
A first switching element is provided for each first neutral wire terminal of each phase of the three-phase AC motor, and each first switching element operates based on a first drive signal from the first drive circuit. A first switching circuit for connecting / disconnecting the first neutral wire terminal and the first neutral wire;
A second switching element is provided for each second neutral wire terminal of each phase of the three-phase AC motor, and each second switching element operates based on a second drive signal from the second drive circuit. And a second switching circuit for connecting / disconnecting the second neutral wire terminal and the second neutral wire,
A series circuit of a first diode and a first charging capacitor is connected between the DC power source and the first neutral line, and a DC voltage of the DC power source is charged to the first charging capacitor, and the charging voltage A first operating power supply circuit that applies an operating voltage to the first driving circuit;
A series circuit of a second diode and a second charging capacitor is connected between the DC power source and the second neutral line, and the DC voltage of the DC power source is charged to the second charging capacitor, and the charging voltage And a second operation power supply circuit for applying an operation voltage to the second drive circuit,
During the driving of the three-phase AC motor, the first neutral wire terminal and the first neutral wire are in a disconnected state, and the second neutral wire terminal and the second neutral wire are connected. When the second neutral wire voltage of the second neutral wire is less than the DC voltage of the DC power source when the state is, the second neutral wire voltage is less than the DC voltage of the DC power source, A current path from the DC power source to the second neutral line through the series circuit of the second operating power supply circuit is formed, and the second charging capacitor is charged with a DC voltage of the DC power source;
During the driving of the three-phase AC motor, the first neutral wire terminal and the first neutral wire are in a connected state, and the second neutral wire terminal and the second neutral wire are not connected. When the first neutral wire voltage of the first neutral wire is less than the DC voltage of the DC power source when the state is, the first neutral wire voltage is less than the DC voltage of the DC power source, A three-phase circuit in which a current path from the DC power source to the first neutral line through the series circuit of the first operating power supply circuit is formed and the first charging capacitor is charged with a DC voltage of the DC power source. Winding switching device for AC motors. In the winding switching device provided in the three-phase AC motor according to claim 1 ,
Each first switching element provided in the first switching circuit is a first MOS transistor including a body diode,
Each second switching element provided in the second switching circuit is a second MOS transistor including a body diode,
All upper arm switching elements of the three-phase inverter circuit are turned off, and at least one of the lower arm switching elements is turned on to charge the first and second charging capacitors of the first and second operating power supply circuits. A winding switching device provided in a three-phase AC motor, wherein a control circuit is provided. In the winding switching device provided in the three-phase AC motor according to claim 2 ,
The control circuit turns off all upper arm switching elements of the three-phase inverter circuit and turns on at least one of the lower arm switching elements before driving the three-phase AC motor. The winding switching device provided in the three-phase AC motor. In the winding switching device provided in the three-phase AC motor according to any one of claims 1 to 3 ,
A winding switching device provided in a three-phase AC motor, wherein a constant voltage circuit is provided in each of the first and second charging capacitors of the first and second operating power supply circuits. In the winding switching device provided in the three-phase AC motor according to any one of claims 1 to 4 ,
A DC voltage booster circuit for boosting the DC voltage of the DC power supply is provided,
A winding switching device provided in a three-phase AC motor, wherein the boosted voltage of the DC voltage booster circuit is applied to the first and second operating power supply circuits. In the winding switching device provided in the three-phase AC motor according to any one of claims 1 to 3 ,
A winding switching device provided in a three-phase AC motor, wherein an operating voltage boosting circuit is provided for boosting the charging voltages of the first and second charging capacitors of the first and second operating power supply circuits, respectively. Each phase winding is composed of a first winding and a second winding, a power receiving terminal is provided at the leading end of the first winding, a leading end of the first winding, and a leading start of the second winding. A three-phase AC motor provided with a first neutral wire terminal at the connecting portion and a second neutral wire terminal at the leading end portion of the second winding;
A three-phase inverter circuit that inputs a DC voltage of a DC power source, converts the DC voltage into a three-phase AC power source, and applies the three-phase AC power source to a power receiving terminal of a corresponding phase of the three-phase AC motor;
A first switching element is provided for each first neutral wire terminal of each phase of the three-phase AC motor, and each first switching element operates based on a first drive signal from the first drive circuit. A first switching circuit for connecting / disconnecting the first neutral wire terminal and the first neutral wire;
A second switching element is provided for each second neutral wire terminal of each phase of the three-phase AC motor, and each second switching element operates based on a second drive signal from the second drive circuit. Detection of a short circuit failure of the switching element of the winding switching device provided in the three-phase AC motor comprising the second switching circuit for connecting / disconnecting the second neutral wire terminal and the second neutral wire. A method,
A connection point of a pull-up resistor and a pull-down resistor each consisting of a series circuit is connected to the power receiving terminal of each phase, the other end of the pull-up resistor is connected to the DC power supply, and the other end of the pull-down resistor is grounded To ground,
The first neutral wire is grounded via a first voltage detection resistor, and the second neutral wire is grounded via a second voltage detection resistor,
When all the upper arm switching elements and all the lower arm switching elements of the three-phase inverter circuit are turned off, and all the first and second switching switching elements of the first and second switching circuits are turned off, When one of the first neutral line and the second neutral line is an intermediate voltage, it is determined that one of the switching elements of the switching circuit on the side of the intermediate voltage has a short circuit failure, and the first When the voltage of the second neutral line is a low voltage lower than the intermediate voltage, it is determined that all the first and second switching elements are not short-circuited. A method for detecting a short circuit failure in a switching element of a switching device. In the short fault detection method of the switching element of the winding switching device provided in the three-phase AC motor according to claim 7 ,
When it is determined that one of the first or second switching elements of the first or second switching circuit is short-circuited,
Only the upper arm switching elements of any one of the upper arm switching elements of the three-phase inverter circuit are sequentially turned on, and the voltages of the first and second neutral lines become higher than the intermediate voltage. A three-phase AC motor characterized in that it is determined that the switching circuit of the phase corresponding to the upper arm switching element that is turned on at that time is a short circuit fault. A method for detecting a short circuit failure in a switching element of a winding switching device provided in the above. In the short circuit fault detection method of the switching element of the winding switching device provided in the three-phase AC motor according to claim 7 or 8 ,
Each of the first and second switching elements provided in the first and second switching circuits is a MOS transistor, and detection of a short circuit failure in the switching element of the winding switching device provided in the three-phase AC motor Method. Each phase winding is composed of a first winding and a second winding, a power receiving terminal is provided at the leading end of the first winding, a leading end of the first winding, and a leading start of the second winding. A three-phase AC motor provided with a first neutral wire terminal at the connecting portion and a second neutral wire terminal at the leading end portion of the second winding;
A three-phase inverter circuit that inputs a DC voltage of a DC power source, converts the DC voltage into a three-phase AC power source, and applies the three-phase AC power source to a power receiving terminal of a corresponding phase of the three-phase AC motor;
A first switching element is provided for each first neutral wire terminal of each phase of the three-phase AC motor, and each first switching element operates based on a first drive signal from the first drive circuit. A first switching circuit for connecting / disconnecting the first neutral wire terminal and the first neutral wire;
A second switching element is provided for each second neutral wire terminal of each phase of the three-phase AC motor, and each second switching element operates based on a second drive signal from the second drive circuit. Open failure detection of the switching element of the winding switching device provided in the three-phase AC motor comprising the second switching circuit for connecting / disconnecting the second neutral wire terminal and the second neutral wire to each other A method,
A connection point of a pull-up resistor and a pull-down resistor each consisting of a series circuit is connected to the power receiving terminal of each phase, the other end of the pull-up resistor is connected to the DC power supply, and the other end of the pull-down resistor is grounded To ground,
The first neutral wire is grounded via a first voltage detection resistor, and the second neutral wire is grounded via a second voltage detection resistor,
When detecting an open failure of the first switching element of the first switching circuit,
All the first switching elements of the first switching circuit are turned on, all the second switching elements of the second switching circuit are turned off,
When only the upper arm switching element of any one phase of all the upper arm switching elements of the three-phase inverter circuit is sequentially turned on and the voltage of the first neutral line becomes equal to or lower than the intermediate voltage, It is determined that the first switching switching element of the phase corresponding to the upper arm switching element that has been operated is open-failed, and when the voltage of the first neutral line becomes higher than the intermediate voltage, Determining that the first switching switching element of the phase corresponding to the upper arm switching element being turned on does not have an open failure;
When detecting an open failure of the second switching element of the second switching circuit,
All the second switching elements of the second switching circuit are turned on, all the first switching elements of the first switching circuit are turned off,
When only the upper arm switching element of any one phase of all the upper arm switching elements of the three-phase inverter circuit is sequentially turned on and the voltage of the second neutral line becomes equal to or lower than the intermediate voltage, It is determined that the second switching switching element of the phase corresponding to the upper arm switching element that has been operated is open-failed, and when the voltage of the second neutral line becomes higher than the intermediate voltage, Opening the switching switching element of the winding switching device provided in the three-phase AC motor, wherein it is determined that the second switching switching element of the phase corresponding to the upper arm switching element that is turned on does not have an open failure. Fault detection method. In open failure detection method of the switching the switching element of the winding switching device provided in the 3-phase AC motor according to claim 1 0,
Each of the first and second switching elements provided in the first and second switching circuits is a MOS transistor, and an open fault detection of the switching element of the winding switching device provided in the three-phase AC motor is provided. Method.