Power conversion device

Abstract

To appropriately perform ASC control of a rotary electric machine while reducing power consumption by supplying a current from a backup power supply only to a drive circuit on one side out of drive circuits on a positive electrode side and a negative electrode side when power supply is lost.SOLUTION: The power conversion device includes a power conversion circuit having a leg provided with a positive-electrode-side switching element, a negative-electrode-side switching element, and a power supply line connecting a connection point at which the positive-electrode-side switching element and the negative-electrode-side switching element are connected in series to the rotary electric machine, a positive-electrode-side driving unit and a negative-electrode-side driving unit of the power conversion circuit that receive supply of a first power supply or a second power supply, and a control circuit that supplies the second power supply to the positive-electrode-side driving unit or the negative-electrode-side driving unit when the first power supply is abnormal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power conversion device. [Background technology]

[0002] In recent years, automobiles equipped with rotating electric machines (hereinafter referred to as "electric vehicles"), such as plug-in hybrid electric vehicles (PHEVs), electric vehicles (EVs), and fuel cell vehicles, have become widespread. These electric vehicles run by converting electric power stored in a high-voltage direct current (DC) power supply (also called a battery) into the rotational force of a rotating electric machine using a power conversion device. The electric motor and generator are collectively called rotating electric machines. Common power conversion devices that convert the power output form to control rotating electric machines include an alternating current / direct current (AC / DC) converter that converts AC power to DC power and an inverter that converts DC power to AC power. The power conversion devices that control these rotating electric machines often include switching elements.

[0003] An electric vehicle is equipped with a low-voltage battery that supplies power to a control device that controls a power conversion device. Generally, the control device receives power from a low-voltage battery of about 12 to 24 V and generates a drive power supply (e.g., a 5 V power supply) for operating the control device. The control device generates a PWM (Pulse Width Modulation) control signal for turning on and off a switching element of the power conversion device. The control device then controls the on and off of the switching element via a drive circuit.

[0004] A power conversion device of an electric vehicle must be able to quickly stop power conversion when the vehicle crashes or an abnormality occurs in the power conversion device. To protect the power conversion device and the rotating electric machine, active short circuit control (hereinafter referred to as ASC (Active Short Circuit) control) is implemented, in which one of the switching elements, either the positive side switching element or the negative side switching element, is forcibly switched to the ON state and the other is forcibly switched to the OFF state. This is a control that creates a so-called three-phase short circuit state, and it is possible to stop the rotating electric machine while preventing excessive current and voltage from being applied to the power conversion device.

[0005] However, if the vehicle crashes, the wiring between the low-voltage battery and the control device may be broken, and the control device will lose power and will be unable to perform ASC control.

[0006] To solve this problem, a technology has been disclosed that provides a backup power supply circuit to back up the low-voltage battery. The backup power supply circuit continues to supply power to the drive circuit that drives and controls the switching elements, enabling ASC control to be performed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 7377650 Summary of the Invention [Problem to be solved by the invention]

[0008] In the technology disclosed in Patent Document 1, when the power conversion device loses power supply from the low-voltage battery, it generates backup power from a high-voltage DC power supply and supplies the power to the drive circuit to execute ASC control. However, a problem occurs in that power consumption increases due to the supply of backup power to the positive and negative drive circuits.

[0009] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a power conversion device that, when power supply from a low-voltage battery is lost, supplies current from a backup power supply to only one of the positive and negative drive circuits, performs ASC control by three-phase short circuit, and appropriately controls a rotating electric machine while reducing power consumption by the backup power supply. [Means for solving the problem]

[0010] The power conversion device according to the present disclosure comprises: a power conversion circuit having a leg provided with a positive-side switching element connected to a positive side of a DC power supply, a negative-side switching element connected to a negative side of the DC power supply, and a power supply line connecting a connection point at which the positive-side switching element and the negative-side switching element are connected in series to a rotating electric machine; a positive electrode side drive unit that receives power from the first power source or the second power source to drive a positive electrode side switching element of the power conversion circuit; a negative electrode side drive unit that receives power from the first power source or the second power source and drives a negative electrode side switching element of the power conversion circuit; and The device is provided with a control circuit that supplies the second power supply to the positive electrode side drive section or the negative electrode side drive section when the first power supply is abnormal. [Effects of the Invention]

[0011] According to the power conversion device disclosed herein, when the power conversion device loses power supply from the low-voltage battery, it supplies current from the backup power supply to only one of the positive and negative drive circuits, performs ASC control due to a three-phase short circuit, and can appropriately control the rotating electric machine while reducing power consumption from the backup power supply. This makes it possible to continue supplying power to the drive circuits that control the switching elements and reliably perform ASC control while reducing power consumption from the backup power supply. Therefore, it is possible to reduce the current consumption of the power conversion device while ensuring reliability, thereby contributing to the reduction of the size, weight, and cost of the power conversion device. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a first configuration diagram of a power conversion device according to a first embodiment. [Figure 2] 2 is a hardware configuration diagram of a control device of the power conversion device according to the first embodiment. FIG. [Figure 3] 2 is a configuration diagram of an input circuit of a switching element of the power conversion device according to the first embodiment. FIG. [Figure 4] FIG. 4 is a second configuration diagram of the power conversion device according to the first embodiment. [Figure 5] FIG. 10 is a first configuration diagram of a power conversion device according to a second embodiment. [Figure 6] FIG. 10 is a second configuration diagram of the power conversion device according to the second embodiment. [Figure 7] FIG. 10 is a configuration diagram of a power conversion device according to a third embodiment. [Figure 8] FIG. 10 is a configuration diagram of a power conversion device according to a fourth embodiment. [Figure 9] FIG. 10 is a configuration diagram of a power conversion device according to a fifth embodiment. [Figure 10] FIG. 13 is a first configuration diagram of a power conversion device according to a sixth embodiment. [Figure 11] FIG. 20 is a second configuration diagram of the power conversion device according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] A power conversion device according to an embodiment of the present disclosure will be described using the drawings. The drawings are schematic, and for the sake of convenience, configurations are omitted or simplified. Furthermore, the relative sizes and positions of components shown in different drawings are not necessarily accurately depicted and may be changed as appropriate. In the following description, similar components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions of them may be omitted to avoid duplication.

[0014] 1. First Embodiment <Configuration of power conversion device> Fig. 1 is a first configuration diagram of a power conversion device 1 according to embodiment 1. The power conversion device 1 shown in Fig. 1 is mounted on an electric vehicle, and is connected to a high-voltage DC power supply 2 on the input side and a rotating electric machine 6 on the output side. The power conversion device 1 is made up of a smoothing capacitor 3, a positive arm 4, a negative arm 5, and a control device 10.

[0015] The positive arm 4 is composed of three positive switching elements 4a to 4c connected to the positive side of the DC power supply 2. The negative arm 5 is composed of three negative switching elements 5a to 5c connected to the negative side of the DC power supply 2. These six switching elements form a power conversion circuit.

[0016] Power supply lines are provided that connect the connection points of the series-connected positive-side switching elements 4a to 4c and the negative-side switching elements 5a to 5c to the coils of the rotating electric machine 6. The positive-side switching elements and the negative-side switching elements are positive-side arms and negative-side arms, respectively, and each pair of positive-side and negative-side arms is connected in series and is called a leg. The power conversion circuit of FIG. 1 has three sets of legs connected to each coil of the rotating electric machine 6. The number of legs is not limited to three, and four or more sets of legs may be provided.

[0017] The three legs in Fig. 1 constitute a power conversion circuit, which converts the DC current supplied from the DC power supply 2 into AC current to drive a rotating electric machine 6. The DC current supplied by the DC power supply 2 is converted into AC current by individually controlling the on / off of the switching elements of the positive arm 4 and the negative arm 5. The smoothing capacitor 3 smoothes the applied voltage that fluctuates during power conversion.

[0018] <Control device> The control device 10 of the power conversion device 1 receives command values ​​such as a torque command and a rotation speed command for the rotating electric machine 6 from the outside. The PWM signal control unit 24 outputs PWM signals to the positive electrode side drive unit 12 and the negative electrode side drive unit 13 to transmit them to the switching elements 4a to 4c and 5a to 5c, respectively, for outputting a target current according to the command values. The positive electrode side drive unit 12 and the negative electrode side drive unit 13 PWM control the switching elements 4a to 4c of the positive electrode side arm 4 and the switching elements 5a to 5c of the negative electrode side arm 5 in accordance with the PWM signals output from the PWM signal control unit 24.

[0019] The control device 10 is supplied with power from an externally provided low-voltage first power source 20. If the power supply from the first power source 20 is interrupted, the control device receives power from a second power source 11 as a backup power source. The second power source 11 receives power from a high-voltage DC power source 2 and steps down the voltage to a low voltage before supplying the power. The second power source 11 is always in a standby state to provide backup in an emergency, and it is desirable to reduce current consumption.

[0020] <Rotating electric machines> The rotating electric machine 6 is a concept that includes an electric motor (motor) and a generator (electric power generator). The rotating electric machine 6 connected to the power conversion device 1 according to the first embodiment may be interpreted as either an electric motor or a generator. The rotating electric machine 6, which has the functions of both an electric motor and a generator, can convert electric power into driving force for power running, and can also convert the driving force back into electric power for regenerative operation with the same structure. The electric motor and the generator basically have the same structure, and both are capable of power running and regenerative operation.

[0021] In FIG. 1, the rotating electric machine 6 is depicted as a three-phase AC rotating electric machine having three-phase coils. A rotating electric machine having more than three phases of coils may also be used. In FIG. 1, the coils of the rotating electric machine 6 are star-connected (star-shaped connected) and the neutral point is shown as floating. The neutral point may also be grounded. The coils of the rotating electric machine 6 may also be delta-connected.

[0022] Normally, the power conversion device 1 converts the electric power supplied from the DC power supply 2 into the rotational force of the rotating electric machine 6 to drive the electric vehicle. When the vehicle decelerates, the regenerative electric power generated by the rotating electric machine 6 is fed to the DC power supply 2 to charge it.

[0023] <Switching element> The positive arm 4 and the negative arm 5 are power conversion circuits in which six switching elements 4a to 4c and 5a to 5c are fully bridge connected. The positive switching elements 4a to 4c are connected to the positive side of the DC power supply 2 and have diodes connected in anti-parallel. The negative switching elements 5a to 5c are connected to the negative side of the DC power supply 2 and have diodes connected in anti-parallel.

[0024] The switching elements 4a to 4c and 5a to 5c are each semiconductors. The switching elements may be composed of, for example, an insulated gate bipolar transistor (IGBT) and a diode connected in anti-parallel between the emitter and collector of the IGBT. The type and number of switching elements are not limited to these. In addition to the combination of an IGBT and a reverse-connected diode, a metal oxide semiconductor field effect transistor (MOSFET) with a built-in parasitic diode between the source and drain, or a silicon carbide (SiC)-MOSFET may be used as a single or multiple switching element. Figure 1 illustrates an example in which an enhancement-type N-channel MOSFET is used, which is controlled to a conductive state when a high-level signal is input and controlled to a non-conductive state when a low-level signal is input. In addition to SiC, wide bandgap semiconductors such as gallium nitride (GaN) and diamond-based materials may also be used as materials for the switching elements.

[0025] <Control device hardware configuration> 2 is a hardware configuration diagram of the control device 10 of the power conversion device 1 according to the first embodiment. In this embodiment, the control device 10 is a control device that controls the power conversion device 1. Each function of the control device 10 is realized by a processing circuit provided in the control device 10. Specifically, the control device 10 includes, as processing circuits, an arithmetic processing device 90 (computer) such as a CPU (Central Processing Unit), a storage device 91 that exchanges data with the arithmetic processing device 90, an input circuit 92 that inputs external signals to the arithmetic processing device 90, and an output circuit 93 that outputs signals from the arithmetic processing device 90 to the outside.

[0026] The arithmetic processing device 90 may include an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, various signal processing circuits, etc. Furthermore, the arithmetic processing device 90 may include a plurality of the same or different types of devices, each performing a different process. The storage device 91 may include a RAM (Random Access Memory) configured to be able to read and write data from the arithmetic processing device 90, a ROM (Read Only Memory) configured to be able to read data from the arithmetic processing device 90, etc. The input circuit 92 includes the first power source 20, is connected to various sensors and switches, and includes interface circuits such as an AD converter and an input circuit that inputs output signals from these sensors and switches to the arithmetic processing device 90. The output circuit 93 includes switching elements 4a to 4c and 5a to 5c, is connected to electrical loads such as switching elements and actuators, and includes interface circuits such as a drive circuit and a communication circuit that converts and outputs output signals from the arithmetic processing device 90 to these electrical loads.

[0027] Each function of the control device 10 is realized by the arithmetic processing device 90 executing software (programs) stored in a storage device 91 such as a ROM, and cooperating with other hardware of the control device 10 such as the storage device 91, an input circuit 92, and an output circuit 93. Setting data such as thresholds and judgment values ​​used by the control device 10 is stored in the storage device 91 such as a ROM as part of the software (programs).

[0028] Each function installed inside the control device 10 may be configured as a software module, or may be configured as a combination of software and hardware.

[0029] <Switching element input circuit> 3 is a configuration diagram of the input circuits of switching elements 4a to 4c and 5a to 5c of the power conversion device 1 according to the first embodiment. This shows an example in which pull-down resistors are provided at the gate terminals of the switching elements. When power is not supplied to the positive electrode side driver 12 or the negative electrode side driver 13, the output to the gate terminals becomes a high impedance (high resistance) state.

[0030] In such a case, by connecting a pull-down resistor to the gate terminal, the input to the gate terminal is fixed to the Low (low potential) side, and the switching element is stabilized in the cut-off state. When a High (high potential) output is generated from the power-supplied positive electrode side driver 12 or negative electrode side driver 13, the input to the gate terminal becomes High (high potential) even if there is a pull-down resistor, and the switching element is stabilized in the conduction state.

[0031] <Power conversion stops in the event of a vehicle malfunction> The power conversion device 1 of an electric vehicle needs to quickly stop power conversion when the vehicle breaks down or an abnormality occurs in the power conversion device 1. At that time, in order to protect the power conversion device 1 and the rotating electric machine 6, ASC control is performed in which one of the switching elements, the positive side switching elements 4a to 4c or the negative side switching elements 5a to 5c, is forcibly switched to the ON state and the other is forcibly switched to the OFF state.

[0032] In the event of a vehicle breakdown or the like, power is supplied from the first power source 20 to the positive electrode side drive unit 12 and the negative electrode side drive unit 13, and the switching elements constituting either the positive electrode side arm 4 or the negative electrode side arm 5 are forcibly controlled to be in an ON state. Then, the other arm is forcibly controlled to be OFF, thereby realizing ASC control.

[0033] In this case, the PWM signal control unit 24 turns on all drive signals 32 transmitted to the positive drive unit 12 and turns off all drive signals 33 transmitted to the negative drive unit 13, thereby turning on all drive signals 32a for the positive switching elements 4a to 4c and turning off all drive signals 33a for the negative switching elements 5a to 5c. Alternatively, the PWM signal control unit 24 turns off all drive signals 32 transmitted to the positive drive unit 12 and turns on all drive signals 33 transmitted to the negative drive unit 13, thereby turning off all drive signals 32a for the positive switching elements 4a to 4c and turning on all drive signals 33a for the negative switching elements 5a to 5c. In this manner, ASC control can be performed.

[0034] <In the event of loss of primary power source> In the event of a vehicle breakdown, external stress may be applied, possibly causing a break in the wiring of the first power source 20, which is a low-voltage battery. In such a situation, the control device 10 loses the first power source. Even in this case, power is supplied from the second power source 11 to perform ASC control.

[0035] If the power supply from the low-voltage battery to the control device 10 as the first power source is cut off due to some abnormality, the power conversion device 1 converts power from the high-voltage DC power source 2 to the second power source 11, and supplies power to the positive electrode side drive unit 12 or the negative electrode side drive unit 13 to perform ASC control of the switching elements. All switching elements on the side to which power supply continues are turned on, and ASC control is performed.

[0036] 1, the positive switching unit 16 receives power from the second power source 11. When the positive switching unit 16 determines that power from the first power source 20 has been lost, it supplies power to the positive driving unit 12 via a power line 14 and transmits an instruction signal to the positive driving unit 12 via a signal line 14a to turn on all of the positive switching elements. The positive driving unit 12 transmits drive signals 32a for all of the positive switching elements 4a to 4c to the positive arm 4, turning them all on.

[0037] At this time, if the positive switching unit 16 can normally supply power and transmit an instruction signal to the positive driving unit 12, it transmits, for example, a Low (low level) signal to the negative switching unit 17 via the signal line 40. In this case, the negative switching unit 17 does not start up and does not supply power to the negative driving unit 13. By doing so, power is supplied from the second power source 11 only to the positive driving unit 12 and not to the negative driving unit 13. This makes it possible to reduce power consumption by the second power source 11. Also, at this time, the output of the negative driving unit 13 to which no power is supplied becomes a high impedance (high resistance) state, and the switching elements 5a to 5c are stably maintained in an off state by the pull-down resistors.

[0038] If the positive switching unit 16 is unable to normally supply power and transmit an instruction signal to the positive driving unit 12, it stops supplying power to the positive driving unit 12 via the power line 14. Then, it transmits, for example, a High (high level) signal to the negative switching unit 17 via the signal line 40.

[0039] When the negative switching unit 17, which has received a High (high level) signal from the positive switching unit 16 via the signal line 40, determines that power from the first power source 20 has been lost, it supplies power to the negative driving unit 13 via the power line 15 and transmits an instruction signal to turn on all of the negative switching elements to the negative driving unit 13 via the signal line 15a. The negative driving unit 13 transmits drive signals 33a for all of the negative switching elements 5a to 5c to the negative arm 5, turning them all on.

[0040] In this way, power is supplied from the second power source 11 only to the negative electrode side drive unit 13, and power is not supplied to the positive electrode side drive unit 12. This reduces power consumption by the second power source 11. In addition, at this time, the output of the positive electrode side drive unit 12 to which power is not supplied is in a high impedance (high resistance) state, and the switching elements 4a to 4c are stably maintained in an off state by the pull-down resistors.

[0041] At this time, if the negative side switching unit 17 can normally supply power and transmit instruction signals to the negative side driving unit 13, it continues to supply power to the negative side driving unit 13 and transmit instruction signals to turn on all of the negative side switching elements. If the negative side switching unit 17 cannot normally supply power and transmit instruction signals to the negative side driving unit 13, it may continue to supply power to the negative side driving unit 13 and transmit instruction signals to turn on all of the negative side switching elements.

[0042] However, if the negative side switching unit 17 is unable to normally supply power and transmit instruction signals to the negative side driving unit 13, it may stop supplying power and transmitting instruction signals to the negative side driving unit 13. By stopping the power supply to both the positive side driving unit 12 and the negative side driving unit 13, the inputs to all switching elements 4a to 4c and 5a to 5c become Low (low level) signals, and all switching elements can be turned off.

[0043] With the above configuration, if the power supply from the first power source to the control device 10 from the low-voltage battery is cut off due to some abnormality, power can be converted from the high-voltage DC power source 2 to the second power source 11 and supplied to the positive side drive unit 12 or the negative side drive unit 13 to perform ASC control of the switching elements. When the first power source 20 is abnormal, the positive side switching unit 16 and the negative side switching unit 17 function as control circuits that supply power from the second power source 11 to the positive side drive unit 12 or the negative side drive unit 13.

[0044] By supplying power only to the positive electrode side drive unit 12 or the negative electrode side drive unit 13, the power consumption of the second power source can be reduced. Therefore, the capacity of the second power source can be limited, which contributes to reducing the size and weight of the power conversion device and reducing costs. ASC control can be reliably performed, ensuring the reliability of the power conversion device, while promoting reductions in size, weight, and cost of the power conversion device.

[0045] <Control by PWM signal control unit when primary power supply is lost> FIG. 4 is a second configuration diagram of the power conversion device 1 according to the first embodiment. This configuration diagram differs from the first configuration diagram in FIG. 1 in that, when the first power source 20 is lost, the PWM signal control unit receives power from the second power source 11 and performs ASC control. This increases the power consumption of the second power source 11 by the amount of the PWM signal control unit. However, since the PWM signal control unit can determine whether each control can be performed, the degree of freedom of control is improved, which offers many advantages. It is possible to shift the determination of loss of the first power source from the positive-side switching unit 16 and the negative-side switching unit 17 to the PWM signal control unit 24, thereby reducing the burden on the positive-side switching unit 16 and the negative-side switching unit 17.

[0046] For example, the priority of the positive electrode side driver 12 and the negative electrode side driver 13 can be switched, and the control method can be switched when switching between both the positive electrode side switch 16 and the negative electrode side switch 17 is not possible, by changing the software. Specifically, the operation of the positive electrode side switch 16 can be controlled by a signal line 38a, and the operation of the negative electrode side switch 17 can be controlled by a signal line 39a. The on / off setting of each switching element can be controlled by the setting of the drive signals 32 and 33 of the PWM signal control unit 24.

[0047] When the first power supply 20 is abnormal, the PWM signal control unit 24 functions as a control circuit that supplies power from the second power supply 11 to the positive electrode side drive unit 12 or the negative electrode side drive unit 13. Even in this case, power consumption of the second power supply 11 can be reduced by limiting power supply to either the positive electrode side drive unit 12 or the negative electrode side drive unit 13.

[0048] 2. Second Embodiment <First configuration diagram of a power conversion device> FIG. 5 is a first configuration diagram of a power conversion device 1 according to the second embodiment. FIG. 5 differs from FIG. 1 according to the first embodiment in that a positive electrode side abnormality detection unit 18 and a negative electrode side abnormality detection unit 19 are provided. The positive electrode side abnormality detection unit 18 in FIG. 5 shares power with the positive electrode side drive unit 12. The negative electrode side abnormality detection unit 19 in FIG. 5 shares power with the negative electrode side drive unit 13. ASC control can be performed by turning on the side of a normal switching element and turning off the other, without turning on the switching element on the side where an abnormality has been detected by the positive electrode side abnormality detection unit 18 and the negative electrode side abnormality detection unit 19.

[0049] The positive electrode side abnormality detection unit 18 monitors the output state of the positive electrode side drive unit 12 via drive signal 32b and the drive states of the switching elements 4a to 4c via signal line 32c, and can detect the presence or absence of an abnormality in the switching elements 4a to 4c by comparing these. If an abnormality is detected in any of the switching elements 4a to 4c, this is communicated to the positive electrode side switching unit 16 via signal line 38. If the positive electrode side abnormality detection unit 18 does not receive power supply from either the first power source 20 or the second power source 11, it outputs via signal line 38 the same signal as when an abnormality is detected.

[0050] The positive electrode side abnormality detection unit 18 and the positive electrode side drive unit 12 share a power source. Therefore, when the positive electrode side abnormality detection unit 18 detects an abnormality, the positive electrode side switching unit 16 stops the power supply through the power line 14. Then, the power supply to the positive electrode side abnormality detection unit 18 is stopped, and the same signal as when the abnormality was detected is output from the signal line 38. As a result, once the positive electrode side abnormality detection unit 18 detects an abnormality, the abnormality signal continues to be output from the signal line 38. Therefore, ASC control is possible by controlling the power line 14 of the positive electrode side switching unit 16 on the side where the abnormality was detected to be in an interrupted state, and continuing to control the power line 15 of the other negative electrode side switching unit 17 to be in a power supply state. Therefore, in order to ensure the reliability of the electric vehicle, the drive unit to which power is supplied from the second power source 11 can be limited to the negative electrode side, thereby reducing the power consumption of the second power source 11.

[0051] The negative side abnormality detection unit 19 monitors the output state of the negative side drive unit 13 via drive signal 33b and the drive states of the switching elements 5a to 5c via signal line 33c, and can detect the presence or absence of an abnormality in the switching elements 5a to 5c by comparing these. If an abnormality is detected in any of the switching elements 5a to 5c, this is transmitted to the negative side switching unit 17 via signal line 39. If the negative side abnormality detection unit 19 does not receive power supply from either the first power source 20 or the second power source 11, it outputs via signal line 39 the same signal as when an abnormality is detected.

[0052] The negative side abnormality detection unit 19 and the negative side drive unit 13 share a power source. Therefore, when the negative side abnormality detection unit 19 detects an abnormality, the negative side switching unit 17 stops the power supply through the power line 15. Then, the power supply to the negative side abnormality detection unit 19 is stopped, and the same signal as when the abnormality was detected is output from the signal line 39. As a result, once the negative side abnormality detection unit 19 detects an abnormality, the abnormality signal continues to be output from the signal line 39. Therefore, ASC control is possible by controlling the power line 15 of the negative side switching unit 17 on the side where the abnormality was detected to be in an interrupted state, and continuing to control the power line 14 of the other positive side switching unit 16 to be in a power supply state. Therefore, in order to ensure the reliability of the electric vehicle, the drive unit to which power is supplied from the second power source 11 can be limited to the positive side, and the power consumption of the second power source 11 can be reduced.

[0053] When the first power source 20 is abnormal, the positive electrode side switching unit 16 and the negative electrode side switching unit 17 function as control circuits that supply the second power source 11 to the positive electrode side driving unit 12 or the negative electrode side driving unit 13. When the first power source 20 is abnormal, the positive electrode side switching unit 16 and the negative electrode side switching unit 17 as control circuits supply the second power source 11 to the negative electrode side driving unit 13 and turn on all of the negative electrode side switching elements 5a to 5c if the positive electrode side abnormality detection unit 18 detects an abnormality in any of the positive electrode side switching elements 4a to 4c, and supply the second power source 11 to the positive electrode side driving unit 12 and turn on all of the positive electrode side switching elements 4a to 4c if the negative electrode side abnormality detection unit 19 detects an abnormality in any of the negative electrode side switching elements 5a to 5c. When the first power source 20 is abnormal, the positive side switching unit 16 and the negative side switching unit 17 as control circuits supply the second power source 11 to the positive side driving unit 12 to turn on all of the positive side switching elements 4a to 4c, or supply the second power source 11 to the negative side driving unit 13 to turn on all of the negative side switching elements 5a to 5c.

[0054] Therefore, in order to ensure the reliability of the electric vehicle, the drive unit to which power is supplied from the second power source 11 can be limited to the positive or negative side, thereby making it possible to reduce the power consumption of the second power source 11.

[0055] <Second configuration diagram of power conversion device> FIG. 6 is a second configuration diagram of the power conversion device 1 according to the second embodiment. This configuration diagram differs from the first configuration diagram of FIG. 5 in that, when the first power source 20 is lost, the PWM signal control unit 24 receives power supply from the second power source 11 and performs ASC control. In this way, the power consumption of the second power source 11 increases by the amount of the PWM signal control unit. However, since the PWM signal control unit can determine whether each control can be performed, the degree of freedom of control is improved, which has many advantages.

[0056] It is possible to transfer the determination of the loss of the first power supply from the positive electrode side switching unit 16 and the negative electrode side switching unit 17 to the PWM signal control unit 24. This also reduces the burden on the positive electrode side switching unit 16 and the negative electrode side switching unit 17.

[0057] Furthermore, the positive electrode side abnormality detection unit 18 and the negative electrode side abnormality detection unit 19 do not need to monitor the drive signals 32b and 33b. Because the signals output by the positive electrode side drive unit 12 and the negative electrode side drive unit 13 are the same as the drive signals 32 and 33 output by the PWM signal control unit 24, the on / off states of the switching elements 4a to 4c and 5a to 5c can be obtained from the signal lines 32c and 33c and read directly by the PWM signal control unit 24 via the signal lines 38b and 39b, thereby making it possible to determine whether or not the switching elements 4a to 4c and 5a to 5c are faulty. Even in this case, power supply can be limited to the positive electrode side drive unit 12 or the negative electrode side drive unit 13, thereby reducing the power consumption of the second power source.

[0058] When the first power supply 20 is abnormal, the PWM signal control unit 24 functions as a control circuit that supplies the second power supply 11 to the positive side drive unit 12 or the negative side drive unit 13. When the first power supply 20 is abnormal, the PWM signal control unit 24 as a control circuit supplies the second power supply 11 to the negative side drive unit 13 and turns on all of the negative side switching elements 5a to 5c if the positive side abnormality detection unit 18 detects an abnormality in any of the positive side switching elements 4a to 4c, and supplies the second power supply 11 to the positive side drive unit 12 and turns on all of the positive side switching elements 4a to 4c if the negative side abnormality detection unit 19 detects an abnormality in any of the negative side switching elements 5a to 5c. When the first power supply 20 is abnormal, the PWM signal control unit 24 as a control circuit supplies the second power supply 11 to the positive side drive unit 12 to turn on all of the positive side switching elements 4a to 4c, or supplies the second power supply 11 to the negative side drive unit 13 to turn on all of the negative side switching elements 5a to 5c.

[0059] 3. Embodiment 3 <Configuration of power conversion device> Fig. 7 is a configuration diagram of the power conversion device 1 according to embodiment 3. Fig. 7 according to embodiment 3 differs from Fig. 5 according to embodiment 2 in that a logic output unit 181 and a logic output unit 191 are provided in the positive electrode side abnormality detection unit 18 and the negative electrode side abnormality detection unit 19.

[0060] The logic output unit 181 outputs a High (high level) voltage of the detection signal when the positive electrode side abnormality detection unit 18 has not detected an abnormality, and outputs a Low (low level) voltage of the detection signal when the positive electrode side abnormality detection unit 18 has detected an abnormality.

[0061] The logic output unit 191 outputs a high (high level) voltage detection signal when the negative electrode side abnormality detection unit 19 has not detected an abnormality, and outputs a low (low level) voltage detection signal when the negative electrode side abnormality detection unit 19 has detected an abnormality.

[0062] When there is no power supply from either the first power source 20 or the second power source 11, the logic output units 181 and 191 lose the power required for operation and therefore output a low voltage. As a result, even if an abnormality occurs in the first power source 20 and an abnormality occurs in the positive electrode side drive unit 12, the positive electrode side arm 4, the negative electrode side drive unit 13, or the negative electrode side arm 5, the logic output unit 181 or 191 outputs a low voltage.

[0063] Therefore, by switching between the positive electrode side drive unit 12 and the negative electrode side drive unit 13 that supply power using the positive electrode side switching unit 16 or the negative electrode side switching unit 17, it is possible to limit the drive unit to which power is supplied from the second power source 11 in order to execute ASC control of the electric vehicle. This makes it possible to reduce the power consumption of the second power source 11.

[0064] 4. Embodiment 4 <Configuration of power conversion device> Fig. 8 is a configuration diagram of a power conversion device 1 according to a fourth embodiment. Compared to Fig. 7 according to the third embodiment, Fig. 8 differs in that the positive electrode abnormality detection unit 18 and the logic output unit 181 are omitted, the positive electrode switching unit 16 is replaced with a positive electrode switching unit 16a and logic circuits 26a and 26b configured with Pch (P-channel) MOSFETs, and the negative electrode switching unit 17 is replaced with a negative electrode switching unit 17a and logic circuits 27a and 27b configured with Nch (N-channel) MOSFETs. The positive electrode switching unit 16a and the logic circuits 26a and 26b, and the negative electrode switching unit 17a and the logic circuits 27a and 27b correspond to the control circuits described in the third embodiment.

[0065] The power conversion device 1 according to the fourth embodiment includes a negative electrode abnormality detection unit 19 and a logic output unit 191. The positive electrode switching unit 16a is a depletion-type P-channel MOSFET that is controlled to a conductive state when a low-level signal is input. The negative electrode switching unit 17a is an enhancement-type N-channel MOSFET that is controlled to a cutoff state when a low-level signal is input.

[0066] When no abnormality is detected, the logic output unit 191 of the negative side abnormality detection unit 19 outputs a high (high level) detection signal voltage from the signal line 39. When an abnormality is detected, the logic output unit 191 of the negative side abnormality detection unit 19 outputs a low (low level) detection signal voltage from the signal line 39.

[0067] <When the first power source is supplied> When the first power source 20 is being supplied, power from the first power source 20 is supplied to the positive side driver 12 and the negative side driver 13 regardless of the voltage level of the logic output unit 191 of the negative side abnormality detector 19. Then, in response to the drive signal 32 output by the PWM signal controller 24, the positive side driver 12 supplies a drive signal 32a to the switching elements 4a to 4c. Furthermore, in response to the drive signal 33 output by the PWM signal controller 24, the negative side driver 13 supplies a drive signal 33a to the switching elements 5a to 5c.

[0068] <When the primary power supply is lost and no abnormality is detected on the negative side> When the first power supply 20 is lost and the negative side abnormality detection unit 19 does not detect an abnormality, the logic output unit 191 of the negative side abnormality detection unit 19 outputs a high detection signal voltage from the signal line 39. Then, the positive side switching unit 16a receives a high output from the logic circuit 26a and is controlled to be cut off, and no power is supplied to the positive side drive unit 12. Therefore, the drive signal 32a of the positive side drive unit 12 becomes a high impedance (high resistance) state, and the switching elements 4a to 4c become low (low level) inputs due to the pull-down resistors and are cut off.

[0069] When the first power supply 20 is lost and the negative side abnormality detection unit 19 does not detect an abnormality, the negative side switching unit 17a receives a High (high level) output from the logic circuit 27a to control the energization, and the negative side drive unit 13 is supplied with power. Then, an instruction signal to turn on all the negative side switching elements is transmitted to the negative side drive unit 13 via the signal line 15a. In response to the instruction from the signal line 15a, the drive signal 33a of the negative side drive unit 13 becomes a High (high level) state input to control the energization of the switching elements 5a to 5c, and ASC control is performed.

[0070] <When the primary power supply is lost and an abnormality is detected on the negative side> When the first power source 20 is lost and the negative side abnormality detection unit 19 detects an abnormality, the logic output unit 191 of the negative side abnormality detection unit 19 outputs a low detection signal voltage from the signal line 39. The positive side switching unit 16a receives a low output from the logic circuit 26a and is energized, and the positive side drive unit 12 is supplied with power. An instruction signal for turning on all the positive side switching elements is transmitted to the positive side drive unit 12 via the signal line 14a. In response to the instruction from the signal line 14a, the drive signal 32a of the positive side drive unit 12 becomes a high state input to control energization of the switching elements 4a to 4c, and ASC control is performed.

[0071] At this time, the negative switching unit 17a receives a low output from the logic circuit 27a and is controlled to be cut off, and power is not supplied to the negative driving unit 13. Therefore, the driving signal 33a of the negative driving unit 13 is in a high impedance state, and the switching elements 5a to 5c are turned off by the pull-down resistors and input to a low level state.

[0072] As described above, the power conversion device 1 according to the fourth embodiment can cope with the loss of the first power source 20 simply by providing the negative electrode abnormality detection unit 19. When the first power source 20 is lost, the ASC control can be realized by appropriately switching between the positive electrode switching unit 16a and the negative electrode switching unit 17a and supplying power to only one drive unit. This ensures the reliability of the power conversion device while reducing the current consumption of the power conversion device, thereby enabling the power conversion device to be made smaller, lighter, and less expensive.

[0073] 5. Embodiment 5 <Configuration of power conversion device> Fig. 9 is a configuration diagram of a power conversion device 1 according to a fifth embodiment. Compared to Fig. 7 according to the third embodiment, Fig. 9 differs in that the negative electrode abnormality detection unit 19 and the logic output unit 191 are omitted, the positive electrode switching unit 16 is replaced with a positive electrode switching unit 16a and logic circuits 26a and 26b configured with PchMOSFETs, the negative electrode switching unit 17 is replaced with a negative electrode switching unit 17a and logic circuits 27a and 27b configured with NchMOSFETs, and a logic circuit 28 is added. The positive electrode switching unit 16a and logic circuits 26a and 26b, the negative electrode switching unit 17a and logic circuits 27a and 27b, and the logic circuit 28 correspond to the control circuits described in the third embodiment.

[0074] The power conversion device 1 according to the fifth embodiment includes a positive-side abnormality detection unit 18 and a logic output unit 181. The positive-side switching unit 16a is a depletion-type PchMOSFET that is controlled to a conductive state when a low-level signal is input. The negative-side switching unit 17a is an enhancement-type NchMOSFET that is controlled to a cutoff state when a low-level signal is input.

[0075] The logic output unit 181 of the positive electrode side abnormality detection unit 18 outputs a high (high level) detection signal voltage when no abnormality is detected, and outputs a low (low level) detection signal voltage from the signal line 38 when an abnormality is detected.

[0076] <When the first power source is supplied> When the first power source 20 is being supplied, power from the first power source 20 is supplied to the positive side driver 12 and the negative side driver 13 regardless of the voltage level of the logic output unit 181 of the positive side abnormality detector 18. Then, in response to the drive signal 32 output by the PWM signal controller 24, the positive side driver 12 supplies a drive signal 32a to the switching elements 4a to 4c. Furthermore, in response to the drive signal 33 output by the PWM signal controller 24, the negative side driver 13 supplies a drive signal 33a to the switching elements 5a to 5c.

[0077] <When the primary power supply is lost and no abnormality is detected on the positive side> When the first power supply 20 is lost and the positive side abnormality detection unit 18 does not detect an abnormality, the logic output unit 181 of the positive side abnormality detection unit 18 outputs a high-level detection signal voltage from the signal line 38. The positive side switching unit 16a receives a low-level output from the logic circuit 26a and is energized, and the positive side drive unit 12 is supplied with power. An instruction signal for turning on all the positive side switching elements is transmitted to the positive side drive unit 12 via the signal line 14a. In response to the instruction from the signal line 14a, the drive signal 32a of the positive side drive unit 12 becomes a high-level input to control energization of the switching elements 4a to 4c, and ASC control is performed.

[0078] When the first power supply 20 is lost and the positive side abnormality detection unit 18 does not detect an abnormality, the negative side switching unit 17a receives a low (low level) output from the logic circuit 27a and is controlled to be cut off. As a result, power is not supplied to the negative side drive unit 13. The output of the negative side drive unit 13 is in a high impedance (high resistance) state. Therefore, the input of the switching elements 5a to 5c is in a low (low level) state due to the pull-down resistors, and they are cut off.

[0079] <When the primary power supply is lost and an abnormality is detected on the positive side> When the first power supply 20 is lost and the positive side abnormality detection unit 18 detects an abnormality, the logic output unit 181 of the positive side abnormality detection unit 18 outputs a low (low level) detection signal voltage from the signal line 38. Then, the positive side switching unit 16a receives a high (high level) output from the logic circuit 26a and is controlled to be cut off, so that no power is supplied to the positive side drive unit 12. The output of the positive side drive unit 12 is in a high impedance (high resistance) state. Therefore, the input of the switching elements 4a to 4c becomes low (low level) by the pull-down resistors and is cut off.

[0080] When the first power supply 20 is lost and the positive side abnormality detection unit 18 detects an abnormality, the negative side switching unit 17a receives a High (high level) output from the logic circuit 27a to control the energization, and the negative side drive unit 13 is supplied with power. Then, an instruction signal to turn on all the negative side switching elements is transmitted to the negative side drive unit 13 via the signal line 15a. In response to the instruction from the signal line 15a, the drive signal 33a of the negative side drive unit 13 becomes a High (high level) input to control the energization of the switching elements 5a to 5c, and ASC control is performed.

[0081] As described above, the power conversion device 1 according to the fifth embodiment can cope with the loss of the first power source 20 simply by providing the positive electrode side abnormality detection unit 18. When the first power source 20 is lost, the ASC control can be realized by appropriately switching between the positive electrode side switching unit 16a and the negative electrode side switching unit 17a and supplying power to only one drive unit. This ensures the reliability of the power conversion device while reducing the current consumption of the power conversion device, thereby enabling the power conversion device to be made smaller, lighter, and less expensive.

[0082] 6. Embodiment 6 <First configuration diagram of a power conversion device> Fig. 10 is a first configuration diagram of a power conversion device 1 according to embodiment 6. Compared to Fig. 5 according to embodiment 2, Fig. 10 differs in that a positive electrode side drive unit abnormality detection unit 48 and a negative electrode side drive unit abnormality detection unit 49 are provided instead of the positive electrode side abnormality detection unit 18 and the negative electrode side abnormality detection unit 19. ASC control can be performed by turning on the switching element on the side of a normal drive unit and turning off the other, without turning on the switching element on the side of a drive unit in which an abnormality has been detected by the positive electrode side drive unit abnormality detection unit 48 and the negative electrode side drive unit abnormality detection unit 49.

[0083] The positive electrode side driver abnormality detection unit 48 shares a power supply with the positive electrode side driver unit 12. Upon receiving the signal line 32c of the positive electrode side driver unit 12, the unit detects an abnormality in the positive electrode side driver unit 12 and transmits the presence or absence of an abnormality to the positive electrode side switching unit 16 via the signal line 38.

[0084] The negative electrode side driver abnormality detection unit 49 shares a power supply with the negative electrode side driver unit 13. Upon receiving the signal line 33c of the negative electrode side driver unit 13, the unit 49 detects an abnormality in the negative electrode side driver unit 13 and transmits the presence or absence of an abnormality to the negative electrode side switching unit 17 via the signal line 39.

[0085] 10, when the first power source 20 is lost and an abnormality occurs in the positive drive unit 12 or the negative drive unit 13, power from the second power source 11, which is a backup power source, can be supplied only to the healthy drive unit without abnormality, thereby achieving ASC control. This ensures the reliability of the power conversion device while reducing the current consumption of the power conversion device, thereby enabling the power conversion device to be made smaller, lighter, and less expensive. The positive switch unit 16 and the negative switch unit 17 correspond to the control circuit described in the second embodiment.

[0086] <Second configuration diagram of power conversion device> Fig. 11 is a second configuration diagram of the power conversion device 1 according to the sixth embodiment. What differs from the first configuration diagram of Fig. 10 is that when the first power source 20 is lost, the PWM signal control unit 24 receives power supply from the second power source 11 and performs ASC control. In this way, the power consumption of the second power source 11 increases by the amount of the PWM signal control unit 24. However, since the PWM signal control unit can determine whether each control can be performed, the degree of freedom of control is improved, which has many advantages.

[0087] It is possible to transfer the determination of the loss of the first power supply from the positive electrode side switching unit 16 and the negative electrode side switching unit 17 to the PWM signal control unit 24. This also reduces the burden on the positive electrode side switching unit 16 and the negative electrode side switching unit 17.

[0088] Furthermore, the burden on the positive and negative switching units 16 and 17 of monitoring the signal lines 38 and 39 of the positive and negative drive unit abnormality detection units 48 and 49 can be reduced. This is because the PWM signal control unit 24 can receive and determine the output signals of the positive and negative drive unit abnormality detection units 48 and 49 via signal lines 48b and 49b. Even in this case, power supply can be limited to the positive and negative drive units 12 and 13, thereby reducing the power consumption of the second power supply. The PWM signal control unit 24 corresponds to the control circuit described in the second embodiment.

[0089] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed herein. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0090] Various aspects of the present disclosure are summarized below as appendices.

[0091] (Appendix 1) a power conversion circuit having a leg provided with a positive-side switching element connected to a positive side of a DC power supply, a negative-side switching element connected to a negative side of the DC power supply, and a power supply line connecting a connection point where the positive-side switching element and the negative-side switching element are connected in series to a rotating electric machine; a positive electrode side drive unit that receives power from a first power source or a second power source to drive a positive electrode side switching element of the power conversion circuit; a negative electrode side drive unit that receives power from the first power source or the second power source and drives a negative electrode side switching element of the power conversion circuit; and A power conversion device including a control circuit that supplies the second power source to the positive electrode side drive unit or the negative electrode side drive unit when the first power source is abnormal. (Appendix 2) the power conversion circuit has a plurality of the legs, The power conversion device according to claim 1, wherein, when the first power supply is abnormal, the control circuit supplies the second power supply to the positive electrode side drive unit to turn on all of the positive electrode side switching elements, or supplies the second power supply to the negative electrode side drive unit to turn on all of the negative electrode side switching elements. (Appendix 3) a positive-side switching element abnormality detection unit that detects an abnormality in the positive-side switching element; a negative-side switching element abnormality detection unit that detects an abnormality in the negative-side switching element; The power conversion device according to claim 2, wherein when an abnormality occurs in the first power supply, if an abnormality is detected by the positive-side switching element abnormality detection unit, the control circuit supplies the second power supply to the negative-side drive unit and brings all of the negative-side switching elements into conduction, and if an abnormality is detected by the negative-side switching element abnormality detection unit, the control circuit supplies the second power supply to the positive-side drive unit and brings all of the positive-side switching elements into conduction. (Appendix 4) The power conversion device according to Appendix 3, wherein when the first power supply is abnormal, if both the positive side switching element abnormality detection unit and the negative side switching element abnormality detection unit detect normality, the control circuit supplies the second power supply to the positive side drive unit to make all of the positive side switching elements conductive, or supplies the second power supply to the negative side drive unit to make all of the negative side switching elements conductive, and if both the positive side switching element abnormality detection unit and the negative side switching element abnormality detection unit detect abnormalities, the control circuit supplies the second power supply to the positive side drive unit to make all of the positive side switching elements conductive, or supplies the second power supply to the negative side drive unit to make all of the negative side switching elements conductive, or turns off all of the positive side switching elements and the negative side switching elements. (Appendix 5) The power conversion device according to claim 3, wherein the positive side switching element abnormality detection unit shares a power supply with the positive side drive unit, the negative side switching element abnormality detection unit shares a power supply with the negative side drive unit, and the positive side switching element abnormality detection unit and the negative side switching element abnormality detection unit output the same level of output as when an abnormality is detected when the power supply is cut off. (Appendix 6) The power conversion device according to claim 5, wherein the positive-side switching element abnormality detection unit and the negative-side switching element abnormality detection unit output a low-level signal when the power supply is cut off or an abnormality is detected. (Appendix 7) a positive-side switching element abnormality detection unit that detects an abnormality in the positive-side switching element; The power conversion device according to claim 2, wherein when an abnormality occurs in the first power supply, if an abnormality is detected by the positive-side switching element abnormality detection unit, the control circuit supplies the second power supply to the negative-side drive unit and turns on all of the negative-side switching elements. (Appendix 8) The power conversion device according to claim 7, wherein when the first power supply is abnormal, if an abnormality is detected by the positive-side switching element abnormality detection unit, the control circuit supplies the second power supply to the negative-side drive unit, turns on all of the negative-side switching elements, and turns off the positive-side drive unit. (Appendix 9) The power conversion device according to Appendix 8, wherein the control circuit transmits the output of the positive-side switching element abnormality detection unit using an N-channel FET and a P-channel FET, and when an abnormality is detected by the positive-side switching element abnormality detection unit in the event of an abnormality in the first power supply, supplies the second power supply to the negative-side drive unit to turn on all of the negative-side switching elements and turn off the positive-side drive unit. (Appendix 10) a negative-side switching element abnormality detection unit that detects an abnormality in the negative-side switching element; The power conversion device according to claim 2, wherein when the first power supply is abnormal, if an abnormality is detected by the negative-side switching element abnormality detection unit, the control circuit supplies the second power supply to the positive-side drive unit and turns on all of the positive-side switching elements. (Appendix 11) The power conversion device according to claim 10, wherein when the first power supply is abnormal, if an abnormality is detected by the negative-side switching element abnormality detection unit, the control circuit supplies the second power supply to the positive-side drive unit to turn on all of the positive-side switching elements and turn off the negative-side drive unit. (Appendix 12) The power conversion device according to claim 11, wherein the control circuit transmits the output of the negative-side switching element abnormality detection unit using an N-channel FET and a P-channel FET, and when an abnormality occurs in the first power supply and an abnormality is detected by the negative-side switching element abnormality detection unit, the control circuit supplies the second power supply to the positive-side drive unit to turn on all of the positive-side switching elements and turn off the negative-side drive unit. (Appendix 13) a positive electrode side drive unit abnormality detection unit that detects an abnormality in the positive electrode side drive unit; and a negative electrode side drive unit abnormality detection unit that detects an abnormality in the negative electrode side drive unit; The power conversion device according to any one of appendixes 2 to 12, wherein the control circuit supplies the second power supply to the negative electrode side drive unit and turns on all of the negative electrode side switching elements when an abnormality is detected by the positive electrode side drive unit abnormality detection unit in the event of an abnormality in the first power supply, and supplies the second power supply to the positive electrode side drive unit and turns on all of the positive electrode side switching elements when an abnormality is detected by the negative electrode side drive unit abnormality detection unit. (Appendix 14) 14. The power conversion device according to claim 1, wherein the second power source is generated from the DC power source. (Appendix 15) 15. The power conversion device according to claim 1, wherein a positive-side switching element and a negative-side switching element of the power conversion circuit are provided with pull-down resistors at their input terminals. [Explanation of symbols]

[0092] REFERENCE SIGNS LIST 1 power conversion device, 2 DC power supply, 4 positive pole side arm, 5 negative pole side arm, 4a, 4b, 4c, 5a, 5b, 5c switching elements, 6 rotating electric machine, 10 control device, 11 second power supply, 12 positive pole side drive unit, 13 negative pole side drive unit, 16, 16a positive pole side switching unit, 17, 17a negative pole side switching unit, 18 positive pole side abnormality detection unit, 19 negative pole side abnormality detection unit, 20 first power supply, 26a, 26b, 27a, 27b, 28 logic circuit, 48 positive pole side drive unit abnormality detection unit, 49 negative pole side drive unit abnormality detection unit, 181, 191 logic output unit

Claims

1. a power conversion circuit having a leg provided with a positive-side switching element connected to a positive side of a DC power supply, a negative-side switching element connected to a negative side of the DC power supply, and a power supply line connecting a connection point where the positive-side switching element and the negative-side switching element are connected in series to a rotating electric machine; a positive electrode side drive unit that receives power from a first power source or a second power source to drive a positive electrode side switching element of the power conversion circuit; a negative electrode side drive unit that receives power from the first power source or the second power source and drives a negative electrode side switching element of the power conversion circuit; and A power conversion device including a control circuit that supplies the second power source to the positive electrode side drive unit or the negative electrode side drive unit when the first power source is abnormal.

2. the power conversion circuit has a plurality of the legs, 2. The power conversion device according to claim 1, wherein, when the first power supply is abnormal, the control circuit supplies the second power supply to the positive electrode side drive unit to turn on all of the positive electrode side switching elements, or supplies the second power supply to the negative electrode side drive unit to turn on all of the negative electrode side switching elements.

3. a positive-side switching element abnormality detection unit that detects an abnormality in the positive-side switching element; a negative-side switching element abnormality detection unit that detects an abnormality in the negative-side switching element; 3. The power conversion device according to claim 2, wherein when an abnormality occurs in the first power supply, if an abnormality is detected by the positive side switching element abnormality detection unit, the control circuit supplies the second power supply to the negative side drive unit to bring all of the negative side switching elements into conduction, and if an abnormality is detected by the negative side switching element abnormality detection unit, the control circuit supplies the second power supply to the positive side drive unit to bring all of the positive side switching elements into conduction.

4. 4. The power conversion device according to claim 3, wherein, when an abnormality occurs in the first power supply, if both the positive side switching element abnormality detection unit and the negative side switching element abnormality detection unit detect normality, the control circuit supplies the second power supply to the positive side drive unit to make all of the positive side switching elements conductive, or supplies the second power supply to the negative side drive unit to make all of the negative side switching elements conductive, and when abnormalities are detected by both the positive side switching element abnormality detection unit and the negative side switching element abnormality detection unit, the control circuit supplies the second power supply to the positive side drive unit to make all of the positive side switching elements conductive, or supplies the second power supply to the negative side drive unit to make all of the negative side switching elements conductive, or brings all of the positive side switching elements and the negative side switching elements into a cut-off state.

5. 4. The power conversion device according to claim 3, wherein the positive side switching element abnormality detection unit shares a power supply with the positive side drive unit, the negative side switching element abnormality detection unit shares a power supply with the negative side drive unit, and the positive side switching element abnormality detection unit and the negative side switching element abnormality detection unit output the same level of signal as when an abnormality is detected when the power supply is cut off.

6. 6. The power conversion device according to claim 5, wherein the positive-side switching element abnormality detection unit and the negative-side switching element abnormality detection unit output a low-level signal when power supply is cut off or an abnormality is detected.

7. a positive-side switching element abnormality detection unit that detects an abnormality in the positive-side switching element; 3. The power conversion device according to claim 2, wherein when an abnormality occurs in the first power supply, if an abnormality is detected by the positive side switching element abnormality detection unit, the control circuit supplies the second power supply to the negative side drive unit and turns on all of the negative side switching elements.

8. 8. The power conversion device according to claim 7, wherein when the first power supply is abnormal, if an abnormality is detected by the positive side switching element abnormality detection unit, the control circuit supplies the second power supply to the negative side drive unit to turn on all of the negative side switching elements and turn off the positive side drive unit.

9. 9. The power conversion device according to claim 8, wherein the control circuit transmits the output of the positive side switching element abnormality detection unit using an N-channel FET and a P-channel FET, and when an abnormality is detected by the positive side switching element abnormality detection unit in the event of an abnormality in the first power supply, the control circuit supplies the second power supply to the negative side drive unit to turn on all of the negative side switching elements and turn off the positive side drive unit.

10. a negative-side switching element abnormality detection unit that detects an abnormality in the negative-side switching element; 3. The power conversion device according to claim 2, wherein when the first power supply is abnormal, if an abnormality is detected by the negative side switching element abnormality detection unit, the control circuit supplies the second power supply to the positive side drive unit and turns on all of the positive side switching elements.

11. 11. The power conversion device according to claim 10, wherein when the first power supply is abnormal, if an abnormality is detected by the negative side switching element abnormality detection unit, the control circuit supplies the second power supply to the positive side drive unit to turn on all of the positive side switching elements and turn off the negative side drive unit.

12. 12. The power conversion device according to claim 11, wherein the control circuit transmits the output of the negative side switching element abnormality detection unit using an N-channel FET and a P-channel FET, and when an abnormality is detected by the negative side switching element abnormality detection unit in the event of an abnormality in the first power supply, the control circuit supplies the second power supply to the positive side drive unit to turn on all of the positive side switching elements and turn off the negative side drive unit.

13. a positive electrode side drive unit abnormality detection unit that detects an abnormality in the positive electrode side drive unit; and a negative electrode side drive unit abnormality detection unit that detects an abnormality in the negative electrode side drive unit; 3. The power conversion device according to claim 2, wherein when an abnormality occurs in the first power supply, if an abnormality is detected by the positive side drive unit abnormality detection unit, the control circuit supplies the second power supply to the negative side drive unit and turns on all of the negative side switching elements, and if an abnormality is detected by the negative side drive unit abnormality detection unit, the control circuit supplies the second power supply to the positive side drive unit and turns on all of the positive side switching elements.

14. The power conversion device according to claim 1 , wherein the second power supply is generated from the DC power supply.

15. The power conversion device according to claim 1 , wherein a positive-side switching element and a negative-side switching element of the power conversion circuit are provided with pull-down resistors at their input terminals.

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