Power conversion device

Abstract

The present application provides a power conversion device which can reduce power consumption and electromagnetic noise of a gate drive circuit without conducting on-off driving of a switching element of a power conversion circuit. The power conversion device of the present application includes a gate power supply switch which conducts on-off supply of power to all or a part of n gate drive circuits, i.e., a target gate drive circuit, and a control circuit which controls the n gate drive circuits and the gate power supply switch. The control circuit determines whether an operation mode in which the gate drive circuit is controlled to conduct on-off driving of the switching element or a non-operation mode in which the gate drive circuit is not controlled, turns on the gate power supply switch when the operation mode is determined, and turns off the gate power supply switch when the non-operation mode is determined.

Description

Technical Field

[0001] This application relates to power conversion devices. Background Technology

[0002] In the technology of Patent Document 1, the inverter device is configured such that when the inverter device is controlled to operate in a second operating mode, the inverter device is controlled to reduce the specified noise generated from the inverter device compared to the first operating mode. Existing technical documents Patent documents

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2008-005659 Summary of the Invention The technical problem that the invention aims to solve

[0004] However, in the technology of Patent Document 1, the switching noise is reduced by changing the carrier frequency used to control the on / off state of the inverter device's switching elements in the second operating mode. Furthermore, in the technology of Patent Document 1, the switching speed is reduced and switching noise is lowered by increasing the gate resistance of the gate drive circuit in the second operating mode. Therefore, in the technology of Patent Document 1, even in the second operating mode, the switching elements of the inverter device are turned on and off via the gate drive circuit, and the electromagnetic noise generated by the operation of the gate drive circuit cannot be reduced.

[0005] However, when the switching elements of power conversion circuits such as non-inverter are turned on and off, the gate drive circuit also consumes power and generates electromagnetic noise.

[0006] Therefore, the purpose of this application is to provide a power conversion device that can reduce the power consumption and electromagnetic noise of the gate drive circuit without requiring the switching elements of the power conversion circuit to be turned on and off. Technical means for solving technical problems

[0007] The power conversion device involved in this application includes: A power conversion circuit having n (n is a natural number greater than 1) switching elements; There are n gate drive circuits, which drive the n switching elements to turn on and off respectively. A gate power switch that turns on and off to supply power to all or part of the n gate drive circuits, i.e., the target gate drive circuits; and A control circuit that controls n gate drive circuits and the gate power switch. The control circuit determines whether it is an operating mode that requires controlling the gate drive circuit to drive the switching element to turn on and off, or a non-operating mode that does not require controlling the gate drive circuit. When it is determined to be the operating mode, the gate power switch is turned on; when it is determined to be the non-operating mode, the gate power switch is turned off. Invention Effects

[0008] According to the power conversion device of the present invention, when it is determined that the non-operating mode does not require control of the gate drive circuit to drive the switching elements of the power conversion circuit to turn on and off, the gate power switch is turned off, thereby not supplying power to the gate drive circuit. This reduces the power consumption of the gate drive circuit and decreases the electromagnetic noise generated by the gate drive circuit. Attached Figure Description

[0009] Figure 1 This is a simplified structural diagram of the power conversion device according to Embodiment 1. Figure 2 This is a simplified structural diagram of the gate drive circuit, gate power switch, and control circuit involved in Embodiment 1. Figure 3 This is a hardware structure diagram of the control circuit involved in Implementation Method 1. Figure 4 This is a simplified structural diagram of the power conversion device involved in Embodiment 2. Figure 5 This is a simplified structural diagram of the gate drive circuit, gate power switch, and control circuit involved in Embodiment 2. Figure 6 This is a simplified structural diagram of the power conversion device involved in Embodiment 3. Figure 7 This is a simplified structural diagram of the gate drive circuit, gate power switch, and control circuit involved in Embodiment 3. Detailed Implementation

[0010] 1. Implementation Method 1 The power conversion device 1 according to Embodiment 1 is described with reference to the accompanying drawings. Figure 1 This is a simplified structural diagram of the power conversion device 1 involved in this embodiment.

[0011] The power conversion device 1 includes a power conversion circuit 10 with n (n is a natural number greater than 1) switching elements 11, n gate drive circuits 20, a gate power switch 30, and a control circuit 40.

[0012] <Power Conversion Circuit> In this embodiment, the power conversion circuit 10 is a power conversion circuit that performs power conversion between a first DC power supply 50 and an AC rotating motor 70 having a three-phase armature winding. Let n = 6, and the power conversion circuit 10 have 6 switching elements 11.

[0013] The stator of the AC rotary motor 70 is provided with a three-phase armature winding of U phase, V phase, and W phase. Permanent magnets are disposed in the rotor of the AC rotary motor 70. The AC rotary motor 70 serves as the driving force source for the wheels of a vehicle, and the power conversion device 1 and the AC rotary motor 70 are mounted on the vehicle.

[0014] Three sets of series circuits are provided corresponding to the armature windings of each of the three phases. These series circuits connect in series a high-potential-side switching element 11H connected to the high-potential side of the first DC power supply 50 and a low-potential-side switching element 11L connected to the low-potential side of the first DC power supply 50. The power conversion circuit 10 includes a total of six switching elements 11: three high-potential-side switching elements 11H and three low-potential-side switching elements 11L. Furthermore, the connection point of the series-connected high-potential-side switching elements 11H and low-potential-side switching elements 11L is connected to the armature winding of the corresponding phase. A filter capacitor 12 is connected between the high-potential side and the low-potential side of the first DC power supply 50.

[0015] In the switching element 11, an IGBT (Insulated Gate Bipolar Transistor) with a diode connected in reverse parallel or a MOSFET (Metal-Oxide Semiconductor Field Effect Transistor) with a diode connected in reverse parallel is used. The gate terminal of each switching element 11 is connected to a respective gate drive circuit 20. Each switching element 11 is turned on or off via the respective gate drive circuit 20 using a control signal output from the control circuit 40.

[0016] <Power System> A first DC power supply 50 supplies power to the power conversion circuit 10. The first DC power supply 50 includes a first energy storage device 51. The first DC power supply 50 may include a DC / DC converter, etc. A contactor 53 is disposed in the connection path between the first DC power supply 50 and the power conversion circuit 10. The contactor 53 is turned on when power is supplied to the power conversion circuit 10, and turned off when power is not supplied to the power conversion circuit 10, or when an abnormality is detected in the first energy storage device 51 and overcharging is prevented. The first energy storage device 51 is connected to an external charging device 55 and can be charged.

[0017] The second DC power supply 60 supplies power to the control circuit 40 and the gate drive circuit 20, etc. The second DC power supply 60 includes a second energy storage device 61. The second DC power supply 60 may include a DC / DC converter, etc.

[0018] DC / DC converter 65 performs power transfer between a first DC power supply 50 (first energy storage device 51) and a second DC power supply 60 (second energy storage device 61). The first DC voltage of the first DC power supply 50 (e.g., approximately 100V to 400V) is higher than the second DC voltage of the second DC power supply 60 (e.g., approximately 12V to 48V). DC / DC converter 65 steps down the power from the first DC power supply 50 and transfers it to the second DC power supply 60. Alternatively, DC / DC converter 65 boosts the power from the second DC power supply 60 and transfers it to the first DC power supply 50.

[0019] <Gate drive circuit, gate power switch> In this embodiment, six gate drive circuits 20 are provided to drive the six switching elements 11Hu to 11Lw to turn on and off, respectively. The power of the second DC power supply 60 is supplied to the six gate drive circuits 20 via the gate power switch 30. That is, all six gate drive circuits 20 turn on and off the target gate drive circuit 20a via the gate power switch 30.

[0020] Figure 2 The diagram shows a simplified circuit structure including an object gate drive circuit 20a, a control circuit 40, a gate power switch 30, and a second DC power supply 60. Other object gate drive circuits 20a are configured similarly. Power from the second DC power supply 60 is also supplied to the other object gate drive circuits 20a via the gate power switch 30.

[0021] The gate drive circuit 20 generates a gate drive signal for turning the switching element 11 on and off based on the pulse signal output from the control circuit 40. The gate drive circuit 20 has a first circuit group 21 connected to the control circuit 40 side and a second circuit group 22 connected to the switching element 11 side. Signals are transmitted between the first circuit group 21 and the second circuit group 22, but they are electrically isolated. The first circuit group 21 and the second circuit group 22 are integrated into an IC chip and become an isolated gate drive IC 23.

[0022] The first circuit group 21 is powered by the second DC power supply 60 via the gate power switch 30 and operates using the supplied power. The gate drive circuit 20 is controlled by the first circuit group 21 and has a switching power supply 24 that supplies power to the second circuit group 22. The second circuit group 22 is powered by the switching power supply 24 and operates using the supplied power.

[0023] The switching power supply 24 is an isolated boost circuit used to boost and output the power of the second DC power supply 60. The switching power supply 24 is configured in flyback mode. The switching power supply 24 has an isolated transformer 24a. One end of the primary winding 24b of the transformer 24a is located on the high-potential side of the second DC power supply 60, and the other end of the primary winding 24b is connected to the low-potential side of the second DC power supply 60 via a switching element 21a provided in the first circuit group 21. One end of the secondary winding 24c of the transformer 24a is connected to the second circuit group 22 via a diode 24e, and the boosted high voltage Vcc2 is provided to the second circuit group 22. The other end of the secondary winding 24c is connected to the output side (cathode side) of the diode 24e via a capacitor 24f. Alternatively, the switching power supply 24 can be configured as a type of switching power supply other than flyback mode.

[0024] When the power of the second DC power supply 60 is supplied via the gate power switch 30, the first circuit group 21 drives the switching element 21a for the switching power supply in the first circuit group 21 to turn on and off, generating a high voltage Vcc2 in the switching power supply 24.

[0025] The gate power switch 30 is turned on or off by the control circuit 40. The gate power switch 30 can be a switching element such as a MOSFET or an electromagnetic switch. One end of the gate power switch 30 is connected to the high-potential side of the second DC power supply 60 via a buck converter 31. The other end of the gate power switch 30 is connected to the first circuit group 21. The potential of the connection path between the other end of the gate power switch 30 and the first circuit group 21 is input to the control circuit 40.

[0026] When the gate power switch 30 is turned on, a low voltage Vcc1 (e.g., around 5V) obtained by stepping down the voltage of the second DC power supply 60 by the buck converter 31 is supplied to the first circuit group 21, and the first circuit group 21 operates. When the first circuit group 21 operates, the switching element 21a for the switching power supply is turned on and off, the switching power supply 24 operates, and a high voltage Vcc2 is supplied to the second circuit group 22, and the second circuit group 22 operates. When the second circuit group 22 operates, a gate drive signal corresponding to the pulse signal of the control circuit 40 is generated. On the other hand, when the gate power switch 30 is turned off, the power of the second DC power supply 60 is not supplied to the first circuit group 21, the operation of the first circuit group 21 stops, the on / off drive of the switching element 21a for the switching power supply stops, the operation of the switching power supply 24 stops, and the high voltage Vcc2 is not supplied to the second circuit group 22. When the operation of the second circuit group 22 stops, no gate drive signal is generated.

[0027] The gate drive circuit 20 (isolated gate drive IC 23) has a temperature detection circuit for detecting the temperature of the switching element 11. The temperature detection circuit is also provided in a first circuit group 21 and a second circuit group 22, respectively. The second circuit group 22 is connected to the switching element 11 side (temperature sensor). The first circuit group 21 is connected to the control circuit 40 side and transmits the detected temperature information to the control circuit 40.

[0028] <Control Circuit> Control circuit 40 controls six gate drive circuits 20 and gate power switch 30. In this embodiment, control circuit 40 controls AC rotary motor 70 via gate drive circuits 20 and power conversion circuit 10. For example, as Figure 3 As shown, the control circuit 40 has a CPU (Central Processing Unit) 90 and a storage device 91 as its core processing circuit. As a processing circuit, it can include ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. The control circuit 40 includes input / output circuits 92, with various sensors connected to the input circuit, and gate drive circuit 20 and gate power switch 30 connected to the output circuit. Furthermore, the control circuit 40 communicates with other control devices 80 using communication standards such as CAN. Each process of the control circuit 40 is implemented by the CPU 90 executing software (programs) stored in the storage device 91 such as ROM and cooperating with other hardware.

[0029] The control circuit 40 generates pulse signals for turning each switching element 11 on and off, and outputs them to each gate drive circuit 20. In this embodiment, the control circuit 40 uses various known control methods for AC rotating motors, calculates voltage command values ​​based on torque command values, and generates pulse signals to turn each switching element 11 on and off based on the voltage command values.

[0030] <Gate power switch on / off> The control circuit 40 determines whether it is an operating mode that requires controlling the gate drive circuit 20 to drive the switching element 11 to turn on and off, or a non-operating mode that does not require controlling the gate drive circuit 20. Then, when it is determined to be an operating mode, the control circuit 40 turns on the gate power switch 30, and when it is determined to be a non-operating mode, the control circuit 40 turns off the gate power switch 30.

[0031] According to this structure, when it is determined that the gate drive circuit 20 is not needed to drive the switching element 11 to turn on and off, the gate power switch 30 is turned off, thereby not supplying power to the gate drive circuit 20. This reduces the power consumption of the gate drive circuit 20 and the electromagnetic noise generated by it.

[0032] In this embodiment, as described above, the gate drive circuit 20 includes a switching power supply 24, which operates when power is supplied to the gate drive circuit 20 via the gate power switch 30. Therefore, when a non-operating mode is determined and the gate power switch 30 is turned off, the operation of the switching power supply 24 of the gate drive circuit 20 ceases. This reduces electromagnetic noise generated by the switching operation of the switching power supply 24.

[0033] When the external charging device 55 is connected to the first energy storage device 51, the control circuit 40 determines it to be in a non-operating mode. The control circuit 40 detects whether the charging device 55 is connected based on information from the circuit controlling the charging of the first energy storage device 51. The external charging device 55 is usually mounted on a stationary object. During charging, the vehicle is stationary, the AC rotary motor 70 does not need to output torque, and the power conversion circuit 10 is in a non-operating state. Therefore, even if the non-operating mode is determined during charging, it is not a problem to turn off the gate power switch 30 and stop the operation of the gate drive circuit 20 and the power conversion circuit 10, thereby reducing the power consumption of the gate drive circuit 20 and reducing the electromagnetic noise generated by the gate drive circuit 20.

[0034] Furthermore, the control circuit 40 can also determine that it is in a non-operation mode when the vehicle speed stops, the rotation of the AC rotary motor 70 stops, or the torque command value of the AC rotary motor 70 is 0. In this case, even if the gate power switch 30 is turned off, there is no problem in stopping the operation of the gate drive circuit 20 and the power conversion circuit 10, which can reduce the power consumption of the gate drive circuit 20 and reduce the electromagnetic noise generated by the gate drive circuit 20.

[0035] <Fault detection function of gate drive circuit> The control circuit 40 has an anomaly detection function to determine whether the gate drive circuit 20 is malfunctioning. For example, the control circuit 40 determines whether there is an anomaly based on whether temperature information is being transmitted normally from the gate drive circuit 20. When the anomaly detection is determined to be in a non-operating mode, the control circuit 40 stops the anomaly detection function; when the anomaly detection is determined to be in an operating mode, the control circuit 40 enables the anomaly detection function.

[0036] According to this structure, when the gate power switch 30 is turned off and the gate drive circuit 20 stops operating in the non-operation mode, it can prevent the gate drive circuit 20 from being mistakenly identified as malfunctioning.

[0037] <Fault detection function of gate power switch> The control circuit 40 has a fault detection function to detect open-circuit or short-circuit faults in the gate power switch 30. In this embodiment, the control circuit 40 detects the potential of the connection path between the gate power switch 30 and the gate drive circuit 20. Then, based on the detected potential and the on / off control state of the gate power switch 30, the control circuit 40 determines a fault in the gate power switch 30. According to this structure, a fault in the gate power switch 30 that is necessary to reduce the power consumption and electromagnetic noise of the gate drive circuit 20 can be determined.

[0038] For example, when the gate power switch 30 is controlled to be turned on, if the detected potential is greater than the threshold, the gate power switch 30 is normally turned on, and therefore the control circuit 40 determines that no fault has occurred in the gate power switch 30. If the detected potential is less than the threshold, the gate power switch 30 is abnormally turned off, and therefore the control circuit 40 determines that an open circuit fault has occurred in the gate power switch 30. On the other hand, when the gate power switch 30 is controlled to be turned off, if the detected potential is greater than the threshold, the gate power switch 30 is abnormally turned on, and therefore the control circuit 40 determines that a short circuit fault has occurred in the gate power switch 30. If the detected potential is less than the threshold, the gate power switch 30 is normally turned off, and therefore the control circuit 40 determines that no fault has occurred in the gate power switch 30.

[0039] 2. Implementation Method 2 The power conversion device 1 according to Embodiment 2 will be described with reference to the accompanying drawings. Descriptions of structural parts identical to those in Embodiment 1 are omitted. The basic structure of the power conversion device 1 according to this embodiment is the same as that in Embodiment 1, but the difference lies in that a portion of the six gate drive circuits 20 is configured as a non-target gate drive circuit 20b that is always powered without passing through the gate power switch 30, thereby altering the processing of the control circuit 40. Figure 4 A simplified structural diagram of the power conversion device 1 according to this embodiment is shown.

[0040] In this embodiment, a portion of the six gate drive circuits 20 (five in this example) are configured as gate drive circuits that are powered on and off via the gate power switch 30, namely target gate drive circuits 20a, while the remaining (one in this example) gate drive circuits 20 are configured as gate drive circuits that are always powered without being powered via the gate power switch 30, namely non-target gate drive circuits 20b.

[0041] <Non-object gate drive circuit> Figure 5The diagram shows a simplified circuit structure including an object gate drive circuit 20a, a non-object gate drive circuit 20b, a control circuit 40, a gate power switch 30, and a second DC power supply 60. The remaining object gate drive circuits 20a are configured similarly.

[0042] The gate drive circuits of the target gate drive circuit 20a and the non-target gate drive circuit 20b are configured the same as those of the gate drive circuit 20 in Embodiment 1, and have a first circuit group 21, a second circuit group 22 and a switching power supply 24.

[0043] Similar to Embodiment 1, power from the second DC power supply 60, obtained by stepping down the voltage of the buck converter 31, is supplied to the target gate drive circuit 20a via the gate power switch 30. The power from the second DC power supply 60, obtained by stepping down the voltage of the buck converter 31, is directly supplied to the non-target gate drive circuit 20b without passing through the gate power switch 30. Regardless of whether the gate power switch 30 is turned on or off, power is always supplied to the first circuit group 21 of the non-target gate drive circuit 20b, and regardless of whether the gate power switch 30 is turned on or off, the switching power supply 24 of the non-target gate drive circuit 20b always generates a high voltage Vcc2.

[0044] Similar to Embodiment 1, the control circuit 40 determines whether it is an operating mode that requires controlling the gate drive circuit 20 to drive the switching element 11 to turn on and off, or a non-operating mode that does not require controlling the gate drive circuit 20. Furthermore, when it is determined to be an operating mode, the control circuit 40 turns on the gate power switch 30, and when it is determined to be a non-operating mode, the control circuit 40 turns off the gate power switch 30.

[0045] In this embodiment, even when the gate power switch 30 is turned off due to the non-operation mode, power is supplied to the non-target gate drive circuit 20b and the circuit operates.

[0046] <Switch Non-Actuation Status Detection Circuit> The power conversion device 1 includes a state detection circuit that detects the state of the power conversion circuit 10. The control circuit 40 detects the state of the power conversion circuit 10 based on the detection information from the state detection circuit. Furthermore, the control circuit 40 performs various controls on the power conversion circuit 10 based on the detected state, or determines an abnormality in the power conversion circuit 10.

[0047] In this embodiment, a switch-off state detection circuit is provided. This switch-off state detection circuit operates using the power supplied to the non-target gate drive circuit 20b, regardless of whether the gate power switch 30 is turned on or off. According to this structure, even in the non-operation mode and when the gate power switch 30 is off, the switch-off state detection circuit can be activated using the power supplied to the non-target gate drive circuit 20b, thereby detecting the state of the power conversion circuit 10 and enabling its use for various control or anomaly detection.

[0048] <Temperature detection circuit without switch linkage> Similar to Embodiment 1, each gate drive circuit 20 has a temperature detection circuit for detecting the temperature of the switching element 11. In this embodiment, the temperature detection circuit of the non-target gate drive circuit 20b is a switch-non-interlocking state detection circuit that operates using the power supplied to the non-target gate drive circuit 20b regardless of the on / off state of the gate power switch 30.

[0049] When in operating mode, the control circuit 40 monitors the temperature state of each switching element 11 based on temperature information detected by the temperature detection circuits of each gate drive circuit 20. For example, when the temperature of any switching element 11 exceeds an overheat threshold, the control circuit 40 performs various known controls to reduce the temperature of the switching element 11. On the other hand, when in non-operating mode, the control circuit 40 monitors the temperature state of the switching element 11 based on temperature information detected by the temperature detection circuit of the non-target gate drive circuit 20b. For example, the control circuit 40 controls the operation of the cooling mechanism that cools the power conversion circuit 10 based on the temperature information detected by the temperature detection circuit of the non-target gate drive circuit 20b in non-operating mode.

[0050] Even in the non-operating mode and when the gate power switch 30 is off, the power supplied to the non-target gate drive circuit 20b can be used to activate the temperature detection circuit of the non-target gate drive circuit 20b, thereby enabling the detection of the temperature of the switching element 11. When the power conversion circuit 10 is not operating, each switching element 11 does not generate heat, there is no deviation in heat generation between the switching elements 11, and the temperature difference decreases. Therefore, in the non-operating mode, the temperature state of all switching elements 11 can be estimated based on the detected temperature information of the switching elements 11 driven by the non-target gate drive circuit 20b. Thus, in the non-operating mode, by supplying power to the non-target gate drive circuit 20b while reducing the power consumption and electromagnetic noise of the target gate drive circuit 20a, the temperature information of the switching elements 11 can be obtained, and the temperature state of the power conversion circuit 10 can be monitored.

[0051] <Switch-linkage status detection circuit> A switch-linkage state detection circuit is provided. This circuit operates when the gate power switch 30 is turned on and stops operating when the gate power switch 30 is turned off, detecting the state of the power conversion circuit 10. In the non-operation mode, when the gate power switch 30 is turned off, if the switch-linkage state detection circuit detects the state normally, the control circuit 40 determines that the gate power switch 30 is in a short-circuit fault state. On the other hand, in the operation mode, when the gate power switch 30 is turned on, if the switch-linkage state detection circuit fails to detect the state normally, the control circuit 40 determines that the gate power switch 30 is in an open-circuit fault state.

[0052] By using the detection information from the switch linkage state detection circuit, faults in the gate power switch 30 can be detected without providing a dedicated circuit for detecting faults in the gate power switch 30. Furthermore, unlike Embodiment 1, this embodiment does not include a circuit for detecting the potential of the connection path between the gate power switch 30 and the gate drive circuit 20.

[0053] <Voltage Detection Circuit with Switch Linkage> In this embodiment, a voltage detection circuit 13 is provided as a state detection circuit for switch linkage to detect the voltage of the power conversion circuit 10. In this embodiment, the voltage detection circuit 13 detects the power supply voltage of the first DC power supply 50. A voltage sensor 14 is provided to detect the voltage between the two terminals of the filter capacitor 12. The output signal of the voltage sensor 14 is input to the voltage detection circuit 13. The voltage detection circuit 13 processes the detected voltage information and outputs it to the control circuit 40. The control circuit 40 detects the power supply voltage based on the output signal of the voltage detection circuit 13, performs various controls on the power conversion circuit 10 based on the detected power supply voltage, or determines any abnormalities in the power conversion circuit 10, etc. The voltage detection circuit 13 can be a detection circuit that detects voltages other than the power supply voltage.

[0054] The voltage detection circuit 13 operates using the supply voltage (in this example, the low voltage Vcc1 generated by the buck converter 31) provided to the second DC power supply 60 of the target gate drive circuit 20a and the high voltage Vcc2 generated by the switching power supply 24 of the target gate drive circuit 20a. Therefore, the voltage detection circuit 13 is a switch-linked state detection circuit that operates when the gate power switch 30 is turned on. The voltage detection circuit 13 is configured as an isolated circuit, with the first circuit group 13a connected to the control circuit 40 side and the second circuit group 13b connected to the voltage sensor 14 side being isolated. The low voltage Vcc1 is input to the first circuit group 13a, and the high voltage Vcc2 is input to the second circuit group 13b. For example, the voltage detection circuit 13 includes an isolated amplifier. The input side circuit of the isolated amplifier is connected to the voltage sensor 14 side as the second circuit group 13b, and the high voltage Vcc2 is input as the operating voltage. The output side circuit of the isolation amplifier is connected to the control circuit 40 side as the first circuit group 13a, and the input low voltage Vcc1 is used as the operating voltage.

[0055] In the non-operating mode, when the gate power switch 30 is turned off, if the power supply voltage detected by the output signal of the voltage detection circuit 13 is greater than a threshold, the control circuit 40 determines that the gate power switch 30 is short-circuited; if the detected power supply voltage is less than the threshold, the control circuit 40 determines that the gate power switch 30 is not faulty. Conversely, in the operating mode, when the gate power switch 30 is turned on, if the power supply voltage detected by the output signal of the voltage detection circuit 13 is less than a threshold, the control circuit 40 determines that the gate power switch 30 is open-circuited; if the detected power supply voltage is greater than the threshold, the control circuit 40 determines that the gate power switch 30 is not faulty.

[0056] 3. Implementation Method 3 The power conversion device 1 according to Embodiment 3 will be described with reference to the accompanying drawings. Descriptions of structural parts identical to those in Embodiments 1 or 2 are omitted. The basic structure of the power conversion device 1 according to this embodiment is the same as that in Embodiments 1 or 2. Similar to Embodiment 2, a portion of the six gate drive circuits 20 is configured as a non-target gate drive circuit 20b that is always powered without passing through the gate power switch 30. However, unlike Embodiment 2, the voltage detection circuit 13 is configured as a switch-non-interlocking state detection circuit. Figure 6 A simplified structural diagram of the power conversion device 1 according to this embodiment is shown.

[0057] Similar to Embodiment 2, a portion of the six gate drive circuits 20 (five in this example) are configured as gate drive circuits that are powered on and off via the gate power switch 30, namely target gate drive circuits 20a, while the remaining (one in this example) gate drive circuits 20 are configured as gate drive circuits that are always powered without being powered via the gate power switch 30, namely non-target gate drive circuits 20b.

[0058] Figure 7 The diagram shows a simplified circuit structure including one target gate drive circuit 20a, one non-target gate drive circuit 20b, a control circuit 40, a gate power switch 30, and a second DC power supply 60. The remaining target gate drive circuits 20a are configured similarly.

[0059] <Voltage Detection Circuit for Non-Interlocking Switches> The voltage detection circuit 13 is configured in the same way as in Embodiment 2, so its description is omitted. However, unlike Embodiment 2, the voltage detection circuit 13 operates using the supply voltage of the second DC power supply 60 provided to the non-target gate drive circuit 20b (in this example, the low voltage Vcc1 generated by the buck converter 31) and the high voltage Vcc2 generated by the switching power supply 24 of the non-target gate drive circuit 20b. That is, the voltage detection circuit 13 is a switch-independent state detection circuit that operates using the power supplied to the non-target gate drive circuit 20b regardless of the on / off state of the gate power switch 30.

[0060] In both operating and non-operating modes, the control circuit 40 can detect the power supply voltage based on the output signal of the voltage detection circuit 13, thereby detecting the state of the power conversion circuit 10. In both operating and non-operating modes, the control circuit 40 can perform various controls on the power conversion circuit 10 based on the detected power supply voltage, or determine any abnormalities in the power conversion circuit 10, etc.

[0061] <Temperature detection circuit with switch linkage> The temperature detection circuit of the gate drive circuit 20a is a switch-linked state detection circuit. This switch-linked state detection circuit operates when the gate power switch 30 is turned on and stops operating when the gate power switch 30 is turned off.

[0062] In the non-operation mode, when the gate power switch 30 is turned off, if the temperature detection circuit of the target gate drive circuit 20a is detecting temperature information normally, the control circuit 40 determines that the gate power switch 30 is in a short-circuit fault state. On the other hand, in the operation mode, when the gate power switch 30 is turned on, if the temperature detection circuit of the target gate drive circuit 20a is not detecting temperature information normally, the control circuit 40 determines that the gate power switch 30 is in an open-circuit fault state.

[0063] In this embodiment, the control circuit 40 detects whether the gate power switch 30 has an open circuit fault or a short circuit fault by comparing the temperature information detected by the output information of the temperature detection circuit of the non-target gate drive circuit 20b based on the switch non-linkage state detection circuit with the temperature information detected by the output information of the temperature detection circuit of the target gate drive circuit 20a based on the switch linkage state detection circuit.

[0064] In the non-operation mode, when the gate power switch 30 is turned off, if the absolute value of the temperature deviation between the temperature detected by the temperature detection circuit of the target gate drive circuit 20a and the temperature detected by the temperature detection circuit of the non-target gate drive circuit 20b is below the allowable judgment value, the control circuit 40 determines that the gate power switch 30 is in a short-circuit fault. If the absolute value of the temperature deviation is greater than the allowable judgment value, the control circuit 40 determines that the gate power switch 30 is not faulty. In the operation mode, when the gate power switch 30 is turned on, if the absolute value of the temperature deviation between the temperature detected by the temperature detection circuit of the target gate drive circuit 20a and the temperature detected by the temperature detection circuit of the non-target gate drive circuit 20b is greater than the allowable judgment value, the control circuit 40 determines that the gate power switch 30 is in an open-circuit fault. If the absolute value of the temperature deviation is below the allowable judgment value, the control circuit 40 determines that the gate power switch 30 is not faulty.

[0065] <Example> (1) In the above embodiments, the power conversion circuit 10 is described as an example of a power conversion circuit that performs power conversion between a first DC power supply 50 and an AC rotating motor 70 having three-phase armature windings. However, the power conversion circuit 10 can be any power conversion circuit as long as it has one or more switching elements that are driven to turn on and off by a gate drive circuit. For example, the power conversion circuit 10 can be various DC / DC converters that boost or buck DC voltage, or an H-bridge circuit that drives a DC motor. In addition, the power conversion circuit 10 can also be a power conversion circuit that converts power supplied to an AC rotating motor having two sets of three-phase armature windings or an AC rotating motor having armature windings other than three phases. Furthermore, the AC rotating motor can be a field winding type AC rotating motor, and the power conversion circuit 10 can include a switching circuit having switching elements that turn on and off the power supplied to the field windings.

[0066] (2) In the above embodiments, the example described is that when the target gate drive circuit 20a's switching power supply 24 stops operating, the gate power switch 30 is turned off, and the operating mode is determined to be non-operating. However, it is also possible to configure the switching power supply 24, which is still powered on the target gate drive circuit 20a via the gate power switch 30, to be shut off when the target gate drive circuit 20a's switching power supply 24 is determined to be non-operating and the gate power switch is turned off. When the power supply to the switching power supply 24 is shut off, the operation of the switching power supply 24 stops, thereby reducing electromagnetic noise generated by the switching operation of the switching power supply 24. In addition, the switching power supply 24 may also be configured to include a switching element independently of the isolated gate drive IC 23, and operate independently of the isolated gate drive IC 23 using the supplied power.

[0067] While this application describes various exemplary embodiments and examples, the various features, methods, and functions described in one or more embodiments are not limited to the application of a particular embodiment and can be applied to the embodiments individually or in various combinations. Therefore, it can be considered that numerous modifications not illustrated are also included within the scope of the technology disclosed in this application. For example, this includes cases where at least one constituent element is modified, added to, or omitted, and cases where at least one constituent element is extracted and combined with constituent elements of other embodiments. Label Explanation

[0068] 1 Power conversion device, 10 Power conversion circuit, 11 Switching element, 13 Voltage detection circuit, 20 Gate drive circuit, 20a Target gate drive circuit, 20b Non-target gate drive circuit, 21 First circuit group, 22 Second circuit group, 24 Switching power supply, 30 Gate power switch, 40 Control circuit.

Claims

1. A power conversion device, characterized in that, include: A power conversion circuit having n switching elements, where n is a natural number greater than or equal to 1; n gate drive circuits are used to drive the n switching elements to turn on and off respectively. A gate power switch that turns on and off the power supply to all or part of the n gate drive circuits, i.e., the target gate drive circuits. as well as A control circuit that controls n gate drive circuits and the gate power switch. The control circuit determines whether it is an operating mode that requires controlling the gate drive circuit to drive the switching element to turn on and off, or a non-operating mode that does not require controlling the gate drive circuit. When it is determined to be the operating mode, the gate power switch is turned on; when it is determined to be the non-operating mode, the gate power switch is turned off.

2. The power conversion device as described in claim 1, characterized in that, The gate drive circuit includes: a first circuit group powered by a power supply and connected to the control circuit side; a second circuit group connected to the switching element side; and a switching power supply controlled by the first circuit group and supplying power to the second circuit group, which supplies power from the power supply to the first circuit group of the target gate drive circuit via the gate power switch. When it is determined to be the non-operation mode and the gate power switch is turned off, the operation of the switching power supply of the target gate drive circuit stops, or the power supply to the switching power supply of the target gate drive circuit is turned off.

3. The power conversion device as described in claim 1 or 2, characterized in that, When an external charging device is connected to an energy storage device that supplies power to the power conversion circuit, the control circuit determines that it is in the non-operation mode.

4. The power conversion device as described in claim 1 or 2, characterized in that, The power of the first energy storage device is supplied to the power conversion circuit. The power of the second energy storage device is supplied to the target gate drive circuit via the gate power switch. Power is transferred between the first energy storage device and the second energy storage device via a converter. When an external charging device is connected to the first energy storage device, the control circuit determines that it is in the non-operation mode.

5. The power conversion device as described in claim 1 or 2, characterized in that, The control circuit has an anomaly detection function to determine anomalies in the gate drive circuit. If the non-operation mode is determined to be present, the abnormality determination function of the object gate drive circuit is stopped. If the operation mode is determined to be as described, the abnormality determination function of the object gate drive circuit is enabled.

6. The power conversion device as described in claim 1 or 2, characterized in that, The n gate drive circuits include: the target gate drive circuit powered via the gate power switch; and the non-target gate drive circuit that is always powered without being powered via the gate power switch. A switch-non-interlocking state detection circuit is provided. This switch-non-interlocking state detection circuit operates using the power supplied to the non-target gate drive circuit regardless of the on / off state of the gate power switch, and detects the state of the power conversion circuit.

7. The power conversion device as described in claim 6, characterized in that, The gate drive circuit includes: a first circuit group powered by a power supply and connected to the control circuit side; a second circuit group connected to the switching element side; and a switching power supply controlled by the first circuit group and supplying power to the second circuit group, which continuously supplies power to the first circuit group of the non-target gate drive circuit regardless of the on / off state of the gate power switch, and the switching power supply of the non-target gate drive circuit continuously generates voltage regardless of the on / off state of the gate power switch. A voltage detection circuit is provided to detect the voltage of the power conversion circuit as a state detection circuit for the switch not being linked. The voltage detection circuit operates using the supply voltage provided to the non-target gate drive circuit and the voltage generated by the switching power supply of the non-target gate drive circuit.

8. The power conversion device as described in claim 6, characterized in that, The gate drive circuit includes a temperature detection circuit for detecting the temperature of the switching element. The temperature detection circuit of the non-target gate drive circuit is a non-interlocking state detection circuit that operates using the power supplied to the non-target gate drive circuit, independent of the on / off state of the gate power switch.

9. The power conversion device as described in claim 7, characterized in that, The gate drive circuit includes a temperature detection circuit for detecting the temperature of the switching element. The temperature detection circuit of the non-target gate drive circuit is a non-interlocking state detection circuit that operates using the power supplied to the non-target gate drive circuit, independent of the on / off state of the gate power switch.

10. The power conversion device as described in claim 1 or 2, characterized in that, The control circuit detected that the gate power switch had an open circuit or short circuit fault.

11. The power conversion device as claimed in claim 10, characterized in that, The control circuit detects the potential of the connection path between the gate power switch and the gate drive circuit, and determines the fault of the gate power switch based on the detected potential and the on / off control state of the gate power switch.

12. The power conversion device as described in claim 1 or 2, characterized in that, A switch linkage state detection circuit is provided. This switch linkage state detection circuit operates when the gate power switch is turned on and stops operating when the gate power switch is turned off, thereby detecting the state of the power conversion circuit. In the non-operation mode, when the gate power switch is turned off, if the switch linkage state detection circuit detects the state normally, the control circuit determines that the gate power switch is in a short-circuit fault. In the operating mode, when the gate power switch is turned on, if the state detection circuit of the switch linkage fails to detect the state normally, the control circuit determines that the gate power switch is in an open circuit fault.

13. The power conversion device as claimed in claim 12, characterized in that, The gate drive circuit includes: a first circuit group powered by a power supply and connected to the control circuit side; a second circuit group connected to the switching element side; and a switching power supply controlled by the first circuit group and supplying power to the second circuit group, supplying power to the first circuit group of the target gate drive circuit via the gate power switch, wherein the switching power supply of the target gate drive circuit generates a voltage when the gate power switch is turned on. A voltage detection circuit is provided to detect the voltage of the power conversion circuit. As a state detection circuit for the switch linkage, the voltage detection circuit operates using the supply voltage provided to the target gate drive circuit and the voltage generated by the switching power supply of the target gate drive circuit.

14. The power conversion device as claimed in claim 12, characterized in that, The gate driving circuit includes a temperature detection circuit for detecting the temperature of the switching element. The temperature detection circuit of the target gate driving circuit is a state detection circuit for the switch linkage. The state detection circuit for the switch linkage operates when the gate power switch is turned on and stops operating when the gate power switch is turned off.

15. The power conversion device as claimed in claim 13, characterized in that, The gate driving circuit includes a temperature detection circuit for detecting the temperature of the switching element. The temperature detection circuit of the target gate driving circuit is a state detection circuit for the switch linkage. The state detection circuit for the switch linkage operates when the gate power switch is turned on and stops operating when the gate power switch is turned off.

16. The power conversion device as claimed in claim 14, characterized in that, The n gate drive circuits include: the target gate drive circuit powered via the gate power switch; and the non-target gate drive circuit that is always powered without being powered via the gate power switch. In each of the states of controlling the gate power switch to be turned on and controlling the gate power switch to be turned off, the control circuit detects whether the gate power switch has an open circuit fault or a short circuit fault by comparing the temperature information detected by the temperature detection circuit of the non-target gate driving circuit and the temperature information detected by the temperature detection circuit of the target gate driving circuit.

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