Control circuit of power converter

Abstract

A control circuit (50) is applied to a system comprising: a rotating electrical machine (10); a power converter (15) electrically connected to a winding (11) of the rotating electrical machine; a power supply (30); a disconnect switch (23a, 23b) provided in an electrical path (22H, 22L) connecting the power supply and the power converter; and a power storage unit (24). The control circuit comprises: an abnormality determination unit (60, 85) for determining whether an abnormality has occurred in the system; and a regeneration prevention unit (81a, 82a, 87, 80, 91, 103, 104) for preventing the occurrence of power regeneration, which causes current to flow from the rotating electrical machine side to the power storage unit. When the abnormality determination unit determines that an abnormality has occurred, the disconnect switch is switched to an open state after the regeneration prevention unit has prevented the occurrence of power regeneration.

Description

[0001] Citation of related applications

[0002] This application is based on Japanese Patent Application No. 2020-109858 filed on June 25, 2020, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a control circuit for a power converter suitable for a system including: a power converter connected to a winding of a rotating electric machine; a power supply; and a power storage unit connected to an electrical path connecting the power supply and the power converter. Background Art

[0004] As a control circuit of this type, as described in Patent Document 1, a circuit is known that executes disconnection control, forcibly opening the switches of the upper and lower arms of a power converter when a system abnormality is determined. When disconnection control is executed, when back electromotive force is generated in the windings due to the rotation of the rotor of the rotating electrical machine, the line voltage of the windings may sometimes become higher than the voltage of the power storage unit. This increase in line voltage may occur, for example, when the rotor's excitation magnetic flux is large or the rotor's rotational speed is high.

[0005] If the line voltage of the windings is higher than the voltage of the power storage unit, even if shutdown control is executed, a phenomenon known as power regeneration occurs, whereby current flows from the rotating electric machine to the power storage unit. This can cause a sudden increase in the DC voltage on the power storage unit side of the power converter, potentially causing failure of at least one of the power storage unit and the power converter.

[0006] To address this problem and prevent power regeneration, the control circuit described in Patent Document 1 performs short-circuit control by turning on the switch of one of the upper and lower arms and turning off the switch of the other arm.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2018-164380 Summary of the Invention

[0010] Some systems including a rotating electrical machine and a power converter also include a disconnect switch, such as a relay, provided in the electrical path connecting the power source and the power converter. In this case, the power storage unit is connected to the side of the electrical path opposite the power source, relative to the disconnect switch.

[0011] If a system abnormality is determined, short-circuit control is performed to prevent power regeneration and the disconnect switch is switched to the open state to protect the system. However, if the disconnect switch is switched to the open state before short-circuit control is performed, the back electromotive force generated by the rotating electrical machine will be used to charge the storage unit, causing the storage unit voltage to rise sharply. This could result in failure of at least one of the storage unit and the power converter. Therefore, to ensure safety, increasing the capacity of the storage unit is a possible option. However, this would increase the cost, size, and weight of the storage unit. Furthermore, the mechanism for preventing power regeneration is not limited to short-circuit control.

[0012] A main object of the present disclosure is to provide a control circuit for a power converter capable of protecting a power storage unit and a power converter.

[0013] The present disclosure relates to a control circuit for a power converter applicable to a system, wherein the system comprises: a rotating electrical machine;

[0014] a power converter electrically connected to the windings of the rotating electrical machine;

[0015] power supply;

[0016] a disconnect switch disposed in an electrical path connecting the power source and the power converter; and

[0017] a power storage unit connected to a side of the electrical path opposite to the power supply relative to the disconnect switch, wherein the control circuit of the power converter includes:

[0018] an abnormality determination unit configured to determine whether an abnormality has occurred in the system; and

[0019] a regeneration prevention unit that prevents the occurrence of electric power regeneration by causing current to flow from the rotating electric machine side toward the power storage unit,

[0020] When the abnormality determination unit determines that an abnormality has occurred, the disconnect switch is switched to an OFF state after the regeneration prevention unit prevents the occurrence of the electric power regeneration.

[0021] The present disclosure includes: an abnormality determination unit that determines whether an abnormality has occurred in the system; and a regeneration prevention unit that prevents the occurrence of power regeneration. Here, if the line-to-line voltage of the winding is higher than the voltage of the storage unit, if the disconnect switch is switched to the open state before the regeneration prevention unit prevents the occurrence of power regeneration, the storage unit may be charged with the back electromotive force generated by the rotating motor, causing the voltage of the storage unit to rise sharply. In this case, at least one of the storage unit and the power converter may fail. In order to prevent the occurrence of such a failure, for example, increasing the capacity of the storage unit is also considered. However, in this case, the cost, volume, and weight of the storage unit will increase.

[0022] Therefore, in the present disclosure, when the abnormality determination unit determines that an abnormality has occurred, the disconnect switch is switched to the open state after the regeneration prevention unit has prevented the occurrence of power regeneration. This prevents a sudden increase in the voltage of the power storage unit, thereby protecting the power storage unit and the power converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above objects, other objects, features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings and the following detailed description.

[0024] Figure 1 It is an overall configuration diagram of the control system according to the first embodiment.

[0025] Figure 2 This is a diagram showing a control circuit and its peripheral configuration.

[0026] Figure 3 This diagram shows the upper and lower arm actuators and their surrounding structures.

[0027] Figure 4 This is a flowchart showing the processing steps of three-phase short-circuit control and shutdown control executed by a microcomputer.

[0028] Figure 5 This is a timing chart showing an example of the processing method of three-phase short-circuit control and shutdown control.

[0029] Figure 6 This is a flowchart showing the steps of the inspection process executed by the microcomputer.

[0030] Figure 7 This is a sequence diagram showing an example of the inspection processing method in the end sequence.

[0031] Figure 8 It is an overall configuration diagram of a control system according to the second embodiment.

[0032] Figure 9 This is a diagram showing a control circuit and its peripheral configuration.

[0033] Figure 10 This diagram shows the upper and lower arm actuators and their surrounding structures.

[0034] Figure 11 This is a diagram showing an OR circuit, a power supply stop unit, and their peripheral configuration.

[0035] Figure 12 This is a flowchart showing the processing steps of three-phase short-circuit control.

[0036] Figure 13 This is a timing chart showing an example of three-phase short-circuit control.

[0037] Figure 14 This is a flowchart showing the processing steps of three-phase short-circuit control and shutdown control executed by a microcomputer.

[0038] Figure 15 This is a flowchart showing the steps of the inspection process executed by the microcomputer.

[0039] Figure 16 It is an overall configuration diagram of a control system according to a third embodiment.

[0040] Figure 17 This is a flowchart showing the steps of a process executed by a microcomputer.

[0041] Figure 18 This is a flowchart showing the steps of the inspection process executed by the microcomputer.

[0042] Figure 19 It is an overall configuration diagram of a control system according to a fourth embodiment.

[0043] Figure 20 This is a flowchart showing the steps of a process executed by a microcomputer.

[0044] Figure 21 This is a flowchart showing the steps of the inspection process executed by the microcomputer.

[0045] Figure 22 This is an overall structural diagram of a control system according to another embodiment. DETAILED DESCRIPTION

[0046] <First embodiment>

[0047] A first embodiment of the control circuit disclosed herein will be described below with reference to the accompanying drawings. The control circuit of this embodiment is suitable for use in a three-phase inverter serving as a power converter. In this embodiment, the control system including the inverter is installed in a vehicle such as an electric vehicle or hybrid vehicle.

[0048] like Figure 1As shown, the control system includes a rotating electrical machine 10 and an inverter 15. The rotating electrical machine 10 is an onboard main engine, and its rotor can transmit power to drive wheels (not shown). In this embodiment, a synchronous machine, more specifically a permanent magnet synchronous machine, is used as the rotating electrical machine 10.

[0049] The inverter 15 has a switching device section 20. The switching device section 20 includes a series connection body of three corresponding upper arm switches SWH and lower arm switches SWL. In each phase, the first end of the winding 11 of the rotating electrical machine 10 is connected to the connection point of the upper arm switch SWH and the lower arm switch SWL. The second end of the winding 11 of each phase is connected at the neutral point. The windings 11 of each phase are arranged in a manner that is staggered by 120° from each other in electrical angle. In addition, in this embodiment, as each switch SWH, SWL, a voltage-controlled semiconductor switching element, more specifically, an IGBT is used. An upper arm diode DH and a lower arm diode DL serving as freewheeling diodes are connected in reverse parallel to the upper arm switch SWH and the lower arm switch SWL.

[0050] The positive terminal of the high-voltage power supply 30 is connected to the collector, serving as the high-potential-side terminal, of each upper arm switch SWH via a high-potential-side electrical path 22H. The negative terminal of the high-voltage power supply 30 is connected to the emitter, serving as the low-potential-side terminal, of each lower arm switch SWL via a low-potential-side electrical path 22L. In this embodiment, the high-voltage power supply 30 is a secondary battery having an output voltage (rated voltage) of, for example, 100 V or higher.

[0051] A first disconnect switch 23a is provided in the high-potential-side electric path 22H, and a second disconnect switch 23b is provided in the low-potential-side electric path 22L. In this embodiment, each of the switches 23a and 23b is a relay.

[0052] The control system includes a precharge switch 23p and a precharge resistor 27. In this embodiment, the precharge switch 23p is a relay. The precharge switch 23p and the precharge resistor 27 are connected in series. The series connection of the precharge switch 23p and the precharge resistor 27 is connected in parallel with the first disconnect switch 23a.

[0053] The inverter 15 includes a smoothing capacitor 24 as a "power storage unit." The smoothing capacitor 24 electrically connects a portion of the high-potential-side electrical path 22H closer to the switching device 20 than the first disconnect switch 23a to a portion of the low-potential-side electrical path 22L closer to the switching device 20 than the second disconnect switch 23b.

[0054] The control system includes an onboard electrical device 25. For example, the electrical device 25 includes at least one of an electric compressor and a DC-DC converter. The electric compressor constitutes the vehicle interior air conditioning system and is driven by power supplied from a high-voltage power supply 30 to circulate the refrigerant in the onboard refrigeration cycle. The DC-DC converter steps down the output voltage of the high-voltage power supply 30 and supplies it to the onboard low-voltage loads. Low-voltage loads include Figure 2 The low voltage power supply 31 is shown. In this embodiment, the low voltage power supply 31 is a secondary battery having an output voltage (rated voltage) lower than the output voltage (rated voltage) of the high voltage power supply 30 (eg, 12V), such as a lead acid battery.

[0055] The inverter 15 includes a discharge resistor 26. The discharge resistor 26 electrically connects a portion of the high-potential electrical path 22H closer to the switching device 20 than the first disconnect switch 23a to a portion of the low-potential electrical path 22L closer to the switching device 20 than the second disconnect switch 23b.

[0056] like Figure 2 As shown, the control system includes a start switch 28. The start switch 28 is, for example, an ignition switch or a push-type start switch, and is operated by a user of the vehicle.

[0057] like Figure 1 and Figure 2 As shown, the control system includes phase current sensors 40, angle sensors 41, and temperature sensors 42. The phase current sensors 40 output current signals corresponding to at least two of the phases flowing through the rotating electrical machine 10. The angle sensor 41 outputs an angle signal corresponding to the electrical angle of the rotating electrical machine 10. The angle sensor 41 is, for example, an MR sensor having a resolver, an encoder, or a magnetoresistive element; in this embodiment, it is a resolver. The temperature sensor 42 outputs a temperature signal corresponding to the temperature of components of the control system, such as components of the rotating electrical machine 10.

[0058] use Figure 2 The structure of the control circuit 50 will be described. The control circuit 50 includes an input circuit 61, an intermediate power supply circuit 62, and first through fifth low-voltage power supply circuits 63 through 67. The positive terminal of the low-voltage power supply 31 is connected to the input circuit 61 via a fuse 32 and a power switch 33. A grounding member, serving as a grounding location, is connected to the negative terminal of the low-voltage power supply 31.

[0059] When the upper ECU (not shown), which serves as a higher-level control device for the control circuit 50, determines that the start switch 28 is switched to the on state, it switches the power switch 33 to the on state. This starts the supply of power from the low-voltage power supply 31 to the control circuit 50. On the other hand, when the upper ECU determines that the start switch 28 is switched to the off state, it switches the power switch 33 to the off state. Specifically, when the upper ECU determines that the start switch 28 is switched to the off state, after a predetermined end sequence is processed, it switches the power switch 33 to the off state. This stops the supply of power from the low-voltage power supply 31 to the control circuit 50.

[0060] The intermediate power supply circuit 62 generates an intermediate voltage Vm (e.g., 6V) by stepping down the output voltage VB of the input circuit 61. The first low-voltage power supply circuit 63 generates a first voltage V1r (e.g., 5V) by stepping down the output voltage Vm of the intermediate power supply circuit 62. The second low-voltage power supply circuit 64 generates a second voltage V2r (e.g., 3.3V) by stepping down the first voltage V1r output from the first low-voltage power supply circuit 63. The third low-voltage power supply circuit 65 generates a third voltage V3r by stepping down the first voltage V1r output from the first low-voltage power supply circuit 63. In this embodiment, the third voltage V3r is a voltage lower than the second voltage V2r (e.g., 1.2V).

[0061] The fourth low-voltage power supply circuit 66 generates a fourth voltage V4r (e.g., 5V) by stepping down the output voltage VB of the input circuit 61. In this embodiment, the fourth voltage V4r has the same value as the first voltage V1r. The fifth low-voltage power supply circuit 67 generates a fifth voltage V5r (e.g., 30V) by stepping up the output voltage VB of the input circuit 61. The input circuit 61 and each power supply circuit 62-67 are located in the low-voltage region of the control circuit 50.

[0062] The first voltage V1r from the first low-voltage power supply circuit 63 is supplied to the phase current sensor 40. This enables the phase current sensor 40 to output a current signal corresponding to the phase current. The current signal is input to the microcomputer 60 via the current interface unit 70 included in the control circuit 50. The microcomputer 60 calculates the phase current based on the input current signal.

[0063] The control circuit 50 includes an excitation circuit 71, an FB interface unit 72, and a resolver-to-digital converter 73. The excitation circuit 71 is configured to operate with the fifth voltage V5r supplied to the fifth low-voltage power supply circuit 67. The excitation circuit 71 supplies a sinusoidal excitation signal to the resolver stator constituting the angle sensor 41. The angle signal output from the resolver stator is input to the resolver-to-digital converter 73 via the FB interface unit 72. The FB interface unit 72 and the resolver-to-digital converter 73 are configured to operate with the first voltage V1r supplied to the first low-voltage power supply circuit 63. The resolver-to-digital converter 73 calculates the electrical angle of the rotating electric machine 10 based on the angle signal from the FB interface unit 72. The calculated electrical angle is input to the microcomputer 60. The microcomputer 60 calculates the electrical angular velocity of the rotating electric machine 10 based on the input electrical angle.

[0064] The control circuit 50 includes a temperature interface unit 74. The temperature signal output from the temperature sensor 42 is input to the microcomputer 60 via the temperature interface unit 74. The temperature interface unit 74 is configured to be operable by the first voltage V1r supplied to the first low-voltage power supply circuit 63. The microcomputer 60 calculates the temperature of the object being detected by the temperature sensor 42 based on the input temperature signal.

[0065] The control circuit 50 includes a first CAN transceiver 75 and a second CAN transceiver 76. The first CAN transceiver 75 and the second CAN transceiver 76 are configured to operate in response to a first voltage V1r supplied to the first low-voltage power supply circuit 63. The microcomputer 60 exchanges information with the first CAN bus 43 and the second CAN bus 44 via the first CAN transceiver 75 and the second CAN transceiver 76.

[0066] Furthermore, the current interface unit 70 , the excitation circuit 71 , the FB interface unit 72 , the resolver-digital converter 73 , the temperature interface unit 74 , and the first and second CAN transceivers 75 and 76 are provided in a low-voltage region of the control circuit 50 .

[0067] The microcomputer 60 is located in a low-voltage area and includes a CPU and peripheral circuits. For example, the peripheral circuits include an input / output unit and an A / D converter for exchanging signals with the outside world. The microcomputer 60 is supplied with a first voltage V1r from a first low-voltage power supply circuit 63, a second voltage V2r from a second low-voltage power supply circuit 64, and a third voltage V3r from a third low-voltage power supply circuit 65.

[0068] The control circuit 50 includes a voltage sensor 77, an overvoltage detector 78, and a state determination unit 79. The voltage sensor 77 is electrically connected to the high-potential-side electrical path 22H and the low-potential-side electrical path 22L, and is configured to operate based on the output voltage VB of the supply input circuit 61 and the fifth voltage V5r of the fifth low-voltage power supply circuit 67. The voltage sensor 77 outputs a voltage signal corresponding to the terminal voltage of the smoothing capacitor 24. The voltage signal output from the voltage sensor 77 is input to the microcomputer 60 and the overvoltage detector 78.

[0069] The overvoltage detection unit 78 is configured to be activated by the first voltage V1r supplied to the first low-voltage power supply circuit 63. The overvoltage detection unit 78 determines whether the terminal voltage of the smoothing capacitor 24, calculated based on the input voltage signal, exceeds its upper limit voltage. If the overvoltage detection unit 78 determines that the terminal voltage exceeds the upper limit voltage, it outputs an overvoltage signal to the microcomputer 60 and the state determination unit 79.

[0070] The state determination unit 79 is configured to be operable by the first voltage V1r supplied to the first low-voltage power supply circuit 63. In this embodiment, the state determination unit 79 is configured as a logic circuit. The voltage sensor 77, the overvoltage detection unit 78, and the state determination unit 79 are provided in the low-voltage region of the control circuit 50.

[0071] The microcomputer 60 functions as a switching command generator that generates switching commands for the switches SWH and SWL of the switching device unit 20 to control the controlled variable of the rotating electrical machine 10 to its command value. The controlled variable is, for example, torque. The microcomputer 60 generates switching commands based on the output signals of the sensors 40 to 42 and 77. Furthermore, the microcomputer 60 generates switching commands to alternately turn on the upper arm switches SWH and the lower arm switches SWL in each phase.

[0072] The control circuit 50 includes an isolated power supply 80, an upper arm driver 81, and a lower arm driver 82. In this embodiment, the upper arm driver 81 is provided separately for each upper arm switch SWH, and the lower arm driver 82 is provided separately for each lower arm switch SWL. Therefore, a total of six drivers 81 and 82 are provided.

[0073] Based on the voltage supplied from the input circuit 61, the isolated power supply 80 generates and outputs an upper-arm drive voltage VdH for the upper-arm driver 81 and a lower-arm drive voltage VdL for the lower-arm driver 82. The isolated power supply 80 and each driver 81, 82 are arranged in the low-voltage and high-voltage regions of the control circuit 50, straddling the boundary between the low-voltage and high-voltage regions. Specifically, the isolated power supply 80 includes upper-arm isolated power supplies individually provided for the three-phase upper-arm drivers 81 and a lower-arm isolated power supply shared by the three-phase lower-arm drivers 82. In this embodiment, each upper-arm isolated power supply and lower-arm isolated power supply are controlled by a shared power supply control unit. Alternatively, a separate lower-arm isolated power supply may be provided for each of the three-phase lower-arm drivers 82.

[0074] Next, use Figure 3 The upper arm driver 81 and the lower arm driver 82 will be described.

[0075] The upper arm driver 81 includes an upper arm driver 81a, which serves as a switch driver, and an upper arm insulation transmission unit 81b. The upper arm driver 81a is located in the high-voltage region. The upper arm insulation transmission unit 81b is located between the low-voltage region and the high-voltage region, straddling the boundary between the low-voltage region and the high-voltage region. The upper arm insulation transmission unit 81b electrically insulates the low-voltage region from the high-voltage region and transmits switching commands output from the microcomputer 60 to the upper arm driver 81a. The upper arm insulation transmission unit 81b is, for example, a photocoupler or a magnetic coupler.

[0076] The upper arm driver 81 includes the upper arm drive unit 81a and the upper arm insulation transmission unit 81b on the high-voltage side thereof, and is configured to be operable by the upper arm drive voltage VdH supplied by the isolated power supply 80. The upper arm driver 81 includes the upper arm insulation transmission unit 81b on the low-voltage side thereof, and is configured to be operable by the first voltage V1r supplied by the first low-voltage power supply circuit 63.

[0077] If the input switching command is an on command, the upper arm drive unit 81a supplies a charging current to the gate of the upper arm switch SWH. This causes the gate voltage of the upper arm switch SWH to exceed the threshold voltage Vth, turning the upper arm switch SWH on. On the other hand, if the input switching command is an off command, the upper arm drive unit 81a causes a discharge current to flow from the gate of the upper arm switch SWH to the emitter side. This causes the gate voltage of the upper arm switch SWH to fall below the threshold voltage Vth, turning the upper arm switch SWH off.

[0078] The upper arm drive unit 81a transmits a fault signal Sgfail indicating an abnormality in the upper arm switch SWH and information on the temperature Tswd of the upper arm switch SWH to the microcomputer 60 via the upper arm insulating transmission unit 81b. The abnormality in the upper arm switch SWH includes at least one of an overheating abnormality, an overvoltage abnormality, and an overcurrent abnormality.

[0079] The upper arm driver 81 transmits the final switching command SWM for the low-voltage range of the upper arm switch SWH to the microcomputer 60. The final switching command is the logical operation of the switching command output from the microcomputer 60 to the upper arm insulation transmission unit 81b and the shutdown command CmdSDN output from the state determination unit 79 to the upper arm insulation transmission unit 81b. If the microcomputer 60 outputs an on command as the switching command, the final switching command SWM is an on command. If the microcomputer 60 outputs an off command as the switching command, the final switching command SWM is an off command.

[0080] The lower arm driver 82 includes a lower arm driver 82a as a switch driver and a lower arm insulation transmission unit 82b. In this embodiment, the configurations of the drivers 81 and 82 are basically the same. Therefore, a detailed description of the lower arm driver 82 will be omitted as appropriate.

[0081] The lower arm driver 82 includes the lower arm drive portion 82a and the lower arm insulation transmission portion 82b on the high-voltage side thereof, and is configured to be operable by the lower arm drive voltage VdL supplied by the isolated power supply 80. The lower arm insulation transmission portion 82b includes the lower arm driver 82 on the low-voltage side thereof, and is configured to be operable by the first voltage V1r supplied by the first low-voltage power supply circuit 63.

[0082] If the input switching command is an on command, the lower arm driving unit 82a supplies a charging current to the gate of the lower arm switch SWL. This causes the gate voltage of the lower arm switch SWL to exceed the threshold voltage Vth, turning the lower arm switch SWL on. On the other hand, if the input switching command is an off command, the lower arm driving unit 82a causes a discharge current to flow from the gate of the lower arm switch SWL to the emitter side. This causes the gate voltage of the lower arm switch SWL to fall below the threshold voltage Vth, turning the lower arm switch SWL off.

[0083] The lower arm drive unit 82a transmits a fault signal Sgfail indicating an abnormality in the lower arm switch SWL and information on the temperature Tswd of the lower arm switch SWL to the microcomputer 60 via the lower arm insulation transmission unit 82b. The abnormality in the lower arm switch SWL includes at least one of an overheating abnormality, an overvoltage abnormality, and an overcurrent abnormality.

[0084] Back to Figure 2As described above, the control circuit 50 includes a fault detection unit 83. The fault detection unit 83 is provided in a low-voltage area and receives a fault signal Sgfail from each driver 81, 82. When the fault signal Sgfail is input from any of the drivers 81, 82, the fault detection unit 83 outputs an abnormality signal to the microcomputer 60 and the state determination unit 79. The abnormality signal input to the microcomputer 60 is stored in the memory 60a as a storage unit included in the microcomputer 60. The memory 60a is a non-temporary physical storage medium other than a ROM (for example, a non-volatile memory other than a ROM).

[0085] The lower arm driver 82 transmits the final switching command SWMon for the low-voltage region of the lower arm switch SWL to the microcomputer 60. The final switching command is a logical operation value of the switching command output from the microcomputer 60 to the lower arm insulation transmission unit 82b and the shutdown command CmdSDN output from the state determination unit 79 to the lower arm insulation transmission unit 82b.

[0086] The monitoring unit 85 is provided in a low-voltage region and is operable by the output voltage VB supplied to the input circuit 61. The monitoring unit 85 has a function of monitoring whether an abnormality occurs in the microcomputer 60 and is composed of, for example, a watchdog counter (WDC) or a function watchdog counter (F-WDC).

[0087] The control circuit 50 includes a relay controller 45. The relay controller 45 is set in a low-voltage area. When the relay controller 45 determines that a relay on command (equivalent to a "switch on command") has been input from the microcomputer 60, the relay controller 45 outputs an on command to the first disconnect switch 23a and the second disconnect switch 23b, and outputs an off command to the pre-charging switch 23p. As a result, the first disconnect switch 23a and the second disconnect switch 23b become connected, and the pre-charging switch 23p becomes disconnected. When the relay controller 45 determines that a relay off command (equivalent to a "switch off command") has been input from the microcomputer 60, the relay controller 45 outputs an off command to the first disconnect switch 23a, the second disconnect switch 23b, and the pre-charging switch 23p. As a result, the first disconnect switch 23a, the second disconnect switch 23b, and the pre-charging switch 23p become disconnected.

[0088] When the relay controller 45 determines that a precharge command has been input from the microcomputer 60, it executes a precharge process for the smoothing capacitor 24. This process simultaneously turns the first disconnect switch 23a off and turns the precharge switch 23p and the second disconnect switch 23b on. This precharge process prevents inrush current from flowing through the smoothing capacitor 24.

[0089] State determination unit 79 determines whether an overvoltage signal from overvoltage detection unit 78 or an abnormality signal from fault detection unit 83 has been input. If state determination unit 79 determines that an overvoltage signal or an abnormality signal has been input, it outputs a shutdown command CmdSDN to the corresponding upper arm driver 81 and lower arm driver 82, which turns off the corresponding upper arm switch SWH and lower arm switch SWL. This executes shutdown control.

[0090] The microcomputer 60 performs three-phase short-circuit control. Figure 4 Next, a description will be given of the three-phase short-circuit control process and the shutdown control process executed by the microcomputer 60. The three-phase short-circuit control is also referred to as ASC (Active Short Circuit) control.

[0091] In step S10, a determination is made as to whether an abnormality has occurred in the control system. In this embodiment, the control system abnormality includes abnormalities in the upper arm switch SWH and the lower arm switch SWL. For example, based on the abnormality signal from the fault detection unit 83, a determination may be made as to whether an abnormality has occurred in any of the upper arm switches SWH and the lower arm switches SWL. In this case, it is also possible to determine whether an abnormality has occurred in any phase or any arm of the upper arm switch SWH or the lower arm switch SWL, and whether the abnormality is an open circuit abnormality or a short circuit abnormality.

[0092] Furthermore, control system abnormalities include sensor abnormalities or communication abnormalities. Sensor abnormalities include abnormalities in at least one of the phase current sensor 40, angle sensor 41, temperature sensor 42, and voltage sensor 77. Abnormalities in the phase current sensor 40 include at least one of an abnormality in the phase current sensor 40 itself and an abnormality in the current interface unit 70. Abnormalities in the angle sensor 41 include at least one of an abnormality in the angle sensor 41 itself, an abnormality in the excitation circuit 71, an abnormality in the FB interface unit 72, and an abnormality in the resolver-to-digital converter 73. Abnormalities in the temperature sensor 42 include at least one of an abnormality in the temperature sensor 42 itself and an abnormality in the temperature interface unit 74.

[0093] The communication abnormality includes an abnormality in at least one of the first CAN transceiver 75 , the second CAN transceiver 76 , the first CAN bus 43 , and the second CAN bus 44 .

[0094] Incidentally, in the present embodiment, the process of step S10 corresponds to an "abnormality determination unit."

[0095] If it is determined in step S10 that no abnormality has occurred, the process proceeds to step S11, where a relay-on command is output to the relay controller 45, and normal control is performed. In this embodiment, normal control refers to generating and outputting a switch command for controlling the control variable of the rotating electrical machine 10 to a command value in order to drive the vehicle. Furthermore, in response to the relay-on command, the first disconnect switch 23a and the second disconnect switch 23b are turned on, and the precharge switch 23p is turned off.

[0096] On the other hand, if it is determined in step S10 that any abnormality has occurred, the process proceeds to step S12 to determine whether electric power regeneration, a phenomenon in which current flows from the rotating electric machine 10 to the smoothing capacitor 24 , has occurred.

[0097] Specifically, for example, the line voltage Vdemf is estimated when back electromotive force is generated in winding 11. If the estimated line voltage Vdemf exceeds the high-side power supply voltage Vdc, it is determined that power regeneration has occurred. Here, the high-side power supply voltage Vdc is the terminal voltage of smoothing capacitor 24 calculated based on the voltage signal from voltage sensor 77. Furthermore, the line voltage Vdemf can be estimated, for example, based on the electrical angular velocity ωe using the formula "Vdemf = K × ωe." K is a constant determined by the magnetic flux φ of the rotor's magnetic poles.

[0098] Alternatively, for example, the line voltage Vdemf may be estimated based on the rotor's mechanical angular velocity instead of the electrical angular velocity ωe. Furthermore, the line voltage Vdemf may be estimated using a value detected by a temperature sensor that detects the temperature of the rotor of the rotating electrical machine 10 or an estimated value from a temperature estimating unit that estimates the rotor's temperature.

[0099] The value compared with the line voltage Vdemf is not limited to the calculated high-side power supply voltage Vdc, but may be a predetermined determination value, for example, which may be set to the minimum value within the normal range of the terminal voltage of the high-voltage power supply 30.

[0100] Incidentally, in the present embodiment, the process of step S12 corresponds to a "safe state determination unit."

[0101] If it is determined in step S12 that power regeneration is not occurring, the control for placing inverter 15 in a safe state is determined to be shutdown control, and the process proceeds to step S13. In step S13, an opening command is output as a switching command for the upper arm switch SWH and the lower arm switch SWL corresponding to three. This executes shutdown control to prevent the occurrence of power regeneration.

[0102] Next, in step S14, a determination is made as to whether the abnormality determined in step S10 has been resolved. If it is determined that the abnormality has not been resolved, the process proceeds to step S12. On the other hand, if it is determined that the abnormality has been resolved, the process proceeds to step S15, where it is determined whether a relay-off command has been output to the relay controller 45 through the processing of step S18, described later, between the determination that the abnormality has occurred in step S10 and the determination that the abnormality has been resolved in step S14. If it is determined in step S15 that a relay-off command has not been output, the process proceeds to step S10.

[0103] During the period from when an abnormality is determined to have occurred in step S10 to when it is determined that the abnormality has been eliminated in step S14 (hereinafter referred to as the abnormality occurrence period), when only the shutdown control among the three-phase short-circuit control and the shutdown control is executed, during the abnormality occurrence period, the relay on instruction (equivalent to the "switch on instruction") continues to be output from the microcomputer 60 to the relay controller 45, and the first disconnect switch 23a and the second disconnect switch 23b are maintained in the on state.

[0104] If it is determined in step S12 that power regeneration has occurred, the control for placing the inverter 15 in a safe state is determined to be three-phase short-circuit control, and the process proceeds to step S 16. In step S16, it is determined whether the three-phase short-circuit control is being executed.

[0105] If it is determined in step S16 that the three-phase short-circuit control is not being executed, the process proceeds to step S17. In step S17, a disconnection instruction is output as a switching instruction for one of the upper arm switch SWH and the lower arm switch SWL corresponding to the three (hereinafter referred to as the disconnection side switch), and a connection instruction is output as a switching instruction for the other arm switch (hereinafter referred to as the connection side switch). Thus, the three-phase short-circuit control is executed. When the process of step S17 is executed, a positive determination is made in the next step S16. In addition, the switching instruction in step S17 is equivalent to a "regeneration prevention instruction".

[0106] For example, when a sensor abnormality or communication abnormality occurs as a control system abnormality, an OFF command is output as a switching command for the corresponding upper arm switch SWH, and an ON command is output as a switching command for the corresponding lower arm switch SWL.

[0107] For example, when an abnormality occurs in the upper arm switch SWH or the lower arm switch SWL as an abnormality in the control system, the following may be performed depending on whether the abnormality is a short-circuit abnormality or an open-circuit abnormality.

[0108] When a short circuit abnormality occurs in at least one switch of one of the upper arm and the lower arm, an on command is output as a switching command for the three switches corresponding to the arm of the upper arm and the lower arm where the short circuit abnormality occurs, and an off command is output as a switching command for the three switches corresponding to the other arm.

[0109] On the other hand, when it is determined that an open circuit abnormality has occurred in at least one switch of one of the upper arm and the lower arm, a switch output corresponding to three of the upper arm and the lower arm that is different from the arm where the open circuit abnormality has occurred is instructed to turn on, and a switch output corresponding to three of the other arm is instructed to turn off.

[0110] Next, in step S18, in order to switch the first disconnect switch 23a and the second disconnect switch 23b to the OFF state, a relay OFF command is output to the relay controller 45. Thereafter, the process proceeds to step S14.

[0111] If the processing of step S18 is completed, or if it is determined in step S16 that three-phase short-circuit control is being executed, the process proceeds to step S14. If it is determined in step S14 that the abnormality determined in step S10 has not been eliminated, the process proceeds to step S12. On the other hand, if it is determined that the abnormality has been eliminated, the process proceeds to step S15, where it is determined whether a relay opening command was output to the relay controller 45 by the processing of step S18 during the period from the determination of the occurrence of the abnormality in step S10 to the determination of the elimination of the abnormality in step S14.

[0112] If it is determined in step S15 that a relay OFF command has been output, the process proceeds to step S19 . In step S19 , a pre-charge command is first output to the relay controller 45 . This executes the pre-charge process. Then, a relay ON command is output to the relay controller 45 .

[0113] Incidentally, in the present embodiment, the microcomputer 60 and the relay controller 45 correspond to an "abnormal time control unit."

[0114] use Figure 5 Three-phase short-circuit control and shutdown control are explained. Figure 5 (a) shows the transition of the output voltage VB of the input circuit 61. Figure 5 (b) shows the transition of the driving state of the first disconnect switch 23a, the second disconnect switch 23b and the pre-charge switch 23p. Figure 5 (c) shows the transition of the terminal voltage VH of the smoothing capacitor 24 . Figure 5 (d) shows the transition of the operating state of the microcomputer 60. Figure 5 (e) shows the transition of the operating state of the inverter 15 .

[0115] Under normal control, at time t1, the microcomputer 60 determines that an abnormality has occurred in the control system. Since the microcomputer 60 determines that the control for setting the inverter 15 to a safe state is three-phase short-circuit control, a switching instruction for executing the three-phase short-circuit control is output from the microcomputer 60. As a result, an off instruction is output as a switching instruction for the disconnect-side switch of the upper arm switch SWH and the lower arm switch SWL corresponding to three, and an on instruction is output as a switching instruction for the connect-side switch. Thus, the three-phase short-circuit control is executed. In addition, in the case where it is determined at time t1 that an abnormality has occurred in the control system, after the disconnection instruction for the upper arm switch SWH and the lower arm switch SWL corresponding to three is output and the shutdown control is executed, the three-phase short-circuit control is executed. This is to prevent the occurrence of short circuits in the upper and lower arms.

[0116] Then, at time t2, a relay disconnect command is output from microcomputer 60 to relay controller 45, thereby switching first disconnect switch 23a and second disconnect switch 23b to the open state. As a result, the discharge current of smoothing capacitor 24 flows through discharge resistor 26, gradually decreasing the terminal voltage of smoothing capacitor 24.

[0117] Then, at time t3, the microcomputer 60 determines that the control for placing the inverter 15 in the safe state is the shutdown control, and outputs an opening command as a switching command to the upper arm switch SWH and the lower arm switch SWL corresponding to three. As a result, the upper arm switch SWH and the lower arm switch SWL are placed in the opening state.

[0118] Then, at time t4, the microcomputer 60 determines that the control system abnormality has been resolved. Therefore, the microcomputer 60 outputs a precharge command to the relay controller 45, and the precharge process is executed. Then, at time t5, the microcomputer 60 outputs a relay-on command to the relay controller 45, turning on the first and second disconnect switches 23a and 23b, and turning off the precharge switch 23p. Normal control then resumes.

[0119] according to Figure 4 The processing shown can prevent the terminal voltage of the smoothing capacitor 24 from rising sharply when it is determined that power regeneration has occurred. As a result, it is possible to prevent the smoothing capacitor 24, the inverter 15, and the electrical equipment 25 from failing. In order to prevent the occurrence of such a failure, it is required to sequentially execute three-phase short-circuit control and switch the first disconnect switch 23a and the second disconnect switch 23b to the disconnect state. In this embodiment, a process is executed to check whether it can be executed in this order. Figure 6This inspection process is described below. This process is executed by the microcomputer 60.

[0120] In step S20, the rotating electrical machine 10 is stopped. This stop process is executed when a command to stop the control system is issued. In this embodiment, this process outputs an OFF command as a switch command for the corresponding upper arm switch SWH and lower arm switch SWL. In this embodiment, if the host ECU determines that the start switch 28 is in the OFF state, the host ECU instructs the microcomputer 60 to execute this stop process. If the microcomputer 60 determines that the execution of the stop process has been issued, it determines that the control system has been stopped and executes a predetermined termination sequence.

[0121] After the stop process of the rotating electrical machine 10 is performed, the process waits in step S21 until the rotation of the rotor of the rotating electrical machine 10 stops. Here, whether the rotation of the rotor stops may be determined based on, for example, the electrical angular velocity.

[0122] If the rotor is determined to have stopped rotating, the process proceeds to step S22, where a process simulating the process performed when a control system abnormality is determined to have occurred is executed. Specifically, an OFF command is output as a switching command for the OFF-side switch of the corresponding upper arm switch SWH or lower arm switch SWL, and an ON command is output as a switching command for the ON-side switch. Incidentally, in this embodiment, the upper arm drive unit 81a and the lower arm drive unit 82a to which the OFF command or ON command is input correspond to the "regeneration prevention unit."

[0123] In step S23, it is checked that the ON-side switch corresponding to number 3 is in the ON state and the OFF-side switch corresponding to number 3 is in the OFF state by the process of step S22. A specific example of the checking method in step S23 will be described below.

[0124] First, the first inspection method will be described. This inspection method is based on the switch's gate voltage and collector-emitter voltage. Specifically, the switch is determined to be in the OFF state if both the gate voltage of the OFF-side switch is below the OFF determination voltage and the collector-emitter voltage of the OFF-side switch is near the terminal voltage of the high-voltage power supply 30. The OFF determination voltage can be set to a value less than the threshold voltage Vth, for example.

[0125] Furthermore, if both the conditions that the gate voltage of the ON-side switch is equal to or greater than the ON determination voltage and the condition that the collector-emitter voltage of the ON-side switch is near 0 V are satisfied, the ON-side switch is determined to be in the ON state. The ON determination voltage can be set to, for example, the same value as the threshold voltage Vth, or a value greater than the threshold voltage Vth and less than the output voltage of the isolated power supply 80. For example, if the ON-side switch is the lower arm switch SWL, the ON determination voltage can be set to, for example, a value greater than the threshold voltage Vth and less than the lower arm drive voltage VdL.

[0126] Next, the second inspection method will be described. This inspection method is based on the final switching command SWMon and the abnormality signal output from the fault detection unit 83. Specifically, if both the final switching command SWMon for the disconnecting switch is determined to be an disconnecting command and the abnormality signal is not stored in the memory 60a, the disconnecting switch is determined to be in the disconnected state.

[0127] Furthermore, when both the condition that the final switch command SW Mon to the closing side switch is an closing command and the condition that no abnormal signal is stored in the memory 60 a are satisfied, it is determined that the closing side switch is in the closing state.

[0128] According to the second inspection process, whether the ON-side switch and the OFF-side switch have reached the intended drive state can be determined using the result of executing normal control to control the torque of the rotary electric machine 10 to the command value.

[0129] In step S23 , when it is determined that the ON-side switch corresponding to three is in the ON state and the OFF-side switch corresponding to three is in the OFF state, it is determined that the three-phase short-circuit control can be normally performed.

[0130] Next, in step S24 , a process is executed to simulate the process to be executed when it is determined that an abnormality has occurred in the control system. Specifically, a relay opening command is output to the relay controller 45 .

[0131] Next, in step S25 , a discharge process of the smoothing capacitor 24 is performed. In the present embodiment, this process is a process of causing the discharge current of the smoothing capacitor 24 to flow through the discharge resistor 26 .

[0132] Next, in step S26, a check is performed to determine whether the first and second disconnect switches 23a, 23b have been switched to the open state by the process in step S25. Specifically, for example, if the high-side power supply voltage Vdc calculated based on the voltage signal from the voltage sensor 77 is lower than the high-side power supply voltage Vdc before step S25 is executed, or if the high-side power supply voltage Vdc calculated based on the voltage signal from the voltage sensor 77 is below a predetermined value near zero, the first and second disconnect switches 23a, 23b may be determined to be switched to the open state. If the first and second disconnect switches 23a, 23b are in the open state, the terminal voltage of the smoothing capacitor 24 will rapidly decrease to zero due to the discharge process. On the other hand, if the first and second disconnect switches 23a, 23b remain closed due to some abnormality, charge will be supplied from the high-voltage power supply 30 to the smoothing capacitor 24 even if the discharge process is executed.

[0133] According to the process of step S26 using the high-side power supply voltage Vdc, it can be reliably determined that the first disconnect switch 23 a and the second disconnect switch 23 b can be switched to the OFF state.

[0134] Furthermore, in step S25 , the discharge of the smoothing capacitor 24 may be accelerated by executing at least one of a process of causing the switching device unit 20 to flow a current through the winding 11 and a process of driving the electric device 25 .

[0135] Next, in step S27, a determination is made as to whether all of the first to third conditions are met. The first condition is the condition that the three-phase short-circuit control is determined to be able to be normally executed in step S23. The second condition is the condition that the first and second disconnect switches 23a, 23b are determined to be able to be switched to the OFF state in step S26. The third condition is the condition that the first and second disconnect switches 23a, 23b are switched to the OFF state after the three-phase short-circuit control is executed. For example, the determination as to whether the third condition is met can be made based on the determination results of steps S23 and S26.

[0136] If it is determined in step S27 that at least one of the first to third conditions does not hold, at least one of the following has occurred: an abnormality preventing normal execution of three-phase short-circuit control; an abnormality preventing the first and second disconnect switches 23a, 23b from being switched to the open state; or an abnormality preventing the sequential execution of three-phase short-circuit control and the switching of the first and second disconnect switches 23a, 23b to the open state. In this case, in step S28, information indicating the occurrence of the abnormality is stored in memory 60a. The process then transitions to step S29. Furthermore, in step S28, a process may be performed to notify the user of the occurrence of the abnormality. Incidentally, in this embodiment, the processes of steps S22 and S24 correspond to the "processing unit," the processes of steps S23, S26, and S27 correspond to the "inspection unit," and the process of step S25 corresponds to the "discharge processing unit."

[0137] If it is determined in step S27 that all the first to third conditions are met, it is determined that the three-phase short-circuit control and the switching of the first disconnector 23a and the second disconnector 23b to the OFF state can be normally performed in sequence.

[0138] In step S29, as a process for completing a predetermined end sequence including steps S20, S21, and S25, power supply from low-voltage power supply 31 to control circuit 50 is stopped. This process is executed when the host ECU switches power switch 33 to the OFF state.

[0139] use Figure 7 , an example of how to execute the end sequence is described. Figure 7 (e) shows the change in the rotation speed Nr of the rotor of the rotating electrical machine 10 . Figure 7 (a) to (d), (f) correspond to the previous Figure 5 (a)~(e).

[0140] By instructing the control system to stop, the rotating electrical machine 10 is stopped. Consequently, at time t1, the rotor's rotational speed Nr begins to decrease. Subsequently, at time t2, it is determined that the rotor has stopped rotating, and the microcomputer 60 outputs an OFF command as a switching command for the OFF-side switch of the corresponding upper arm switch SWH or lower arm switch SWL, and an ON command as a switching command for the ON-side switch. The process of step S23 is then executed.

[0141] Then, at time t3, a relay opening command is output from the microcomputer 60 to the relay controller 45. Then, at time t4, the discharge process of the smoothing capacitor 24 is executed, and the terminal voltage VH of the smoothing capacitor 24 starts to decrease toward zero.

[0142] Thereafter, at time t5, a normal determination is made by the process of step S27, and the process of step S29 is executed. As a result, the output voltage VB of the input circuit 61 decreases toward 0.

[0143] According to the present embodiment described in detail above, the following effects can be obtained.

[0144] If the microcomputer 60 determines that an abnormality has occurred in the control system, it outputs an on command to the three corresponding on-side switches and an off command to the three corresponding off-side switches. It then outputs a relay off command to the relay controller 45. After the three corresponding on-side switches are turned on and the three corresponding off-side switches are turned off, the microcomputer 60 switches the first and second disconnect switches 23a and 23b to their off states. This reliably prevents a sudden increase in the terminal voltage of the smoothing capacitor 24, thereby protecting the smoothing capacitor 24, the inverter 15, and the electrical equipment 25.

[0145] If the microcomputer 60 determines that a control system abnormality has occurred, and if power regeneration is occurring, it outputs an on command to the on-side switch, an off command to the off-side switch, and a relay off command to the relay controller 45. On the other hand, if the microcomputer 60 determines that a control system abnormality has occurred, and if power regeneration is not occurring, it continues to output the relay on command to the relay controller 45 and maintains the first and second disconnect switches 23a and 23b in the on state. Thus, if the control system abnormality is subsequently determined to have resolved, there is no need to output the precharge command and relay on command. As a result, the recovery time required from the resolution of the control system abnormality to the resumption of normal control can be shortened.

[0146] The microcomputer 60 performs steps S22 and S24, which simulate the processing performed when it is determined that an abnormality has occurred in the control system. In step S27, the microcomputer 60 determines whether the three-phase short-circuit control and the switching of the first and second disconnect switches 23a and 23b to the open state can be performed normally. This ensures that the three-phase short-circuit control and the switching of the first and second disconnect switches 23a and 23b to the open state can be performed normally.

[0147] After the relay-off command is output to the relay controller 45, the discharge process for the smoothing capacitor 24, included in the termination sequence, is executed. The microcomputer 60 then determines whether the first and second disconnect switches 23a and 23b can be switched to the OFF state based on the decrease in high-side power supply voltage Vdc caused by the discharge process. By utilizing the discharge process in the termination sequence, the termination sequence can be completed quickly.

[0148] <Modification of the First Embodiment>

[0149] The control system may include a DC current sensor that detects the DC current flowing in the high-potential side electrical path 22H and the low-potential side electrical path 22L. In this case, Figure 4 In step S12 , the microcomputer 60 may determine that electric power regeneration has occurred when it is determined that a DC current is flowing when shutdown control is executed based on the detection value of the DC current sensor.

[0150] If the control system includes a sensor for detecting line voltage, Figure 4 In step S12, the line voltage to be compared with the high-voltage side power supply voltage Vdc may not be an estimated value but a detected value of the line voltage.

[0151] ·exist Figure 4 In step S19, when the high-side power supply voltage Vdc is higher than the threshold, the precharge instruction may not be output.

[0152] ·exist Figure 4 In the process of , the process of steps S12 and S13 may not be performed. In this case, when a positive determination is made in step S10, the process proceeds to step S16.

[0153] For example, if there is a limit on the execution time of the three-phase short-circuit control due to thermal limitations of the winding 11 and the switchgear unit 20, the Figure 4 When a positive determination is made in step S12, a process of reducing the rotation speed of the rotor is executed by driving control of the rotary electric machine 10. This enables rapid switching to shutdown control.

[0154] · It is also possible to configure each cut-off switch 23a, 23b to have a function of monitoring its own driving state and transmit the monitored driving state to the microcomputer 60. In this case, instead of Figure 6 In the processing of steps S25 and S26, the microcomputer 60 may execute processing for determining that each of the disconnect switches 23a and 23b is switched to the OFF state when it is determined that the monitored driving state is the OFF state.

[0155] You can also Figure 6Step S27 is replaced with a process that determines whether all of the first to fifth conditions are met. The fourth condition can be, for example, that the deviation between the first time from the start of step S22 to the determination in step S23 that three-phase short-circuit control can be normally executed and the first predetermined time is within a predetermined range. Furthermore, the fifth condition can be, for example, that the deviation between the second time from the start of step S24 to the determination in step S26 that the first and second disconnect switches 23a and 23b can be switched to the open state is within a predetermined range.

[0156] The process of determining whether the three-phase short-circuit control and the switching of the first disconnecting switch 23a and the second disconnecting switch 23b to the open state can be normally performed in sequence may not be included in the end sequence.

[0157] <Second embodiment>

[0158] Hereinafter, referring to the accompanying drawings, the second embodiment will be described focusing on the differences from the first embodiment. Figure 8 and Figure 9 As shown in Figure 2, the structure of the control system is partially changed. Figure 8 and Figure 9 For convenience, the previous Figures 1 to 3 The same structures are denoted by the same symbols.

[0159] The inverter 15 includes a discharge switch 29. The discharge switch 29 is connected in series with the discharge resistor 26. The series connection of the discharge switch 29 and the discharge resistor 26 electrically connects a portion of the high-potential-side electrical path 22H that is closer to the switching device unit 20 than the first disconnect switch 23a with a portion of the low-potential-side electrical path 22L that is closer to the switching device unit 20 than the second disconnect switch 23b. In this embodiment, the discharge switch 29 is an N-channel MOSFET and is included in the control circuit 50.

[0160] like Figure 9 As shown, the control circuit 50 includes a low-voltage side ASC command unit 84, an OR circuit 86, and a power supply stop unit 87. The low-voltage side ASC command unit 84, the OR circuit 86, and the power supply stop unit 87 are provided in the low-voltage region. The power supply stop unit 87 is configured to be operable by the fourth voltage V4r supplied to the fourth low-voltage power supply circuit 66.

[0161] When the low-voltage ASC command CmdASC is input from the state determination unit 79 , the low-voltage ASC command unit 84 forcibly sets the switching command input to the corresponding lower arm driver 82 to an ON command regardless of the switching command output from the microcomputer 60 .

[0162] use Figure 9 and Figure 10 , the structure of the high voltage area in the control circuit 50 is described.

[0163] The control circuit 50 includes an abnormality power supply 90 and a high-voltage side ASC command unit 91. The low-arm drive voltage VdL of the isolated power supply 80 is supplied to the high-voltage side ASC command unit 91.

[0164] The abnormal power supply 90 generates the abnormal driving voltage Veps by supplying the output voltage VH of the smoothing capacitor 24. In this embodiment, various power supplies, such as a switching power supply, can be used as the abnormal power supply 90. The high-potential side of the smoothing capacitor 24 is connected to the input side of the abnormal power supply 90. The control unit of the abnormal power supply 90 controls the abnormal driving voltage Veps output from the output side of the abnormal power supply 90 to a target voltage.

[0165] Furthermore, in this embodiment, the control unit of the abnormal power supply 90 activates the abnormal power supply 90 at the moment when the input voltage thereof reaches a predetermined voltage Vα, during the period from when the input voltage thereof begins to rise due to power supply from the smoothing capacitor 24 until the input voltage reaches the output voltage of the smoothing capacitor 24. In this embodiment, activation of the abnormal power supply 90 means that the control unit of the abnormal power supply 90 begins to control the abnormal drive voltage Veps to a target voltage. By initiating this control, the abnormal drive voltage Veps begins to rise toward the target voltage. By activating the abnormal power supply 90 at the moment when the predetermined voltage Vα is reached, the abnormal drive voltage Veps of the abnormal power supply 90 is set to a state that can be controlled early. In this embodiment, the predetermined voltage Vα is set as the startup voltage of the control unit.

[0166] In the high voltage region of the control circuit 50, a first limiting diode 102 is provided in a gate charging path connecting the lower arm drive unit 82a and the gate of the lower arm switch SWL. The first limiting diode 102 is provided with its anode connected to the lower arm drive unit 82a. Figure 10 In FIG, the gate discharge path of the lower arm switch SWL is omitted from illustration.

[0167] The control circuit 50 includes an abnormality switch 103. The abnormality switch 103 connects the output side of the abnormality power supply 90 to the common path 104. The gate of each lower arm switch SWL is connected to the common path 104 via each second limiting diode 105. The second limiting diode 105 is provided in a state where the anode is connected to the common path 104 side. The second limiting diode 105 is used to prevent the charging current output from the lower arm drive unit 82a to the gate of the lower arm switch SWL from flowing to the common path 104 side. In addition, a parallel connection of a plurality of second limiting diodes 105 can also be provided for the gate of each lower arm switch SWL.

[0168] Next, use Figure 11 The OR circuit 86, power supply stop unit 87, and their surrounding structures are described below. The OR circuit 86 includes first through fourth resistors 86a, 86d, and first and second switches 86e, 86f. The first end of the first resistor 86a is connected to the microcomputer 60, and the first end of the second resistor 86b is connected to the ground. The second end of the first resistor 86a is connected to the monitoring unit 85 via the third resistor 86c.

[0169] The fourth low-voltage power supply circuit 66 is connected to the first end of the fourth resistor 86d, and the second end of the fourth resistor 86d is connected to the ground via the first switch 86e. The first determination signal Sg1 from the monitoring unit 85 is supplied to the base of the first switch 86e. The second end of the first resistor 86a is connected to the ground via the second switch 86f. The base of the second switch 86f is connected to the connection point between the fourth resistor 86d and the first switch 86e.

[0170] The microcomputer 60 has a self-monitoring function. If the microcomputer 60 determines that no abnormality has occurred, it sets the logic level of the second determination signal Sg2 to "H." In this case, the logic level of the abnormality notification signal FMCU, which is the output signal of the OR circuit 86, also changes to "H." On the other hand, if the microcomputer 60 determines that an abnormality has occurred, it sets the logic level of the second determination signal Sg2 to "L." In this case, the logic level of the abnormality notification signal FMCU also changes to "L."

[0171] The monitoring unit 85 has a function of monitoring whether an abnormality has occurred in the microcomputer 60, and is composed of, for example, a monitoring counter (WDC) or a function monitoring counter (F-WDC). When the monitoring unit 85 determines that no abnormality has occurred in the microcomputer 60, the logic of the first determination signal Sg1 is set to L. In this case, the first switch 86e and the second switch 86f are maintained in the off state, and the logic of the abnormality notification signal FMCU becomes H. On the other hand, when the monitoring unit 85 determines that an abnormality has occurred in the microcomputer 60, the logic of the first determination signal Sg1 is set to H. In this case, the first switch 86e and the second switch 86f are switched to the on state, and the logic of the abnormality notification signal FMCU is set to L. Incidentally, in this embodiment, the microcomputer 60 and the monitoring unit 85 are equivalent to the "abnormality determination unit".

[0172] The abnormality notification signal FMCU is input to the power supply stop unit 87. The power supply stop unit 87 includes an abnormality detection circuit 87a and a switch 87b. The first end of the switch 87b is connected to a ground, and the second end of the switch 87b is connected to the connection point of the first and second voltage-dividing resistors 96a, 96b included in the control circuit 50. The first end of the series connection of the first and second voltage-dividing resistors 96a, 96b is connected to the input circuit 61, and the second end of the series connection is connected to the ground. The UVLO terminal of the isolated power supply 80 is connected to the connection point of the first and second voltage-dividing resistors 96a, 96b. If the control unit of the isolated power supply 80 determines that the voltage input to this connection point, namely the judgment voltage Vjin, is lower than the low-voltage threshold VUVLO, it executes a low-voltage malfunction prevention process that shuts down the isolated power supply 80. On the other hand, if the control unit of the isolated power supply 80 determines that the input judgment voltage Vjin exceeds a release threshold (<VB) that is higher than the low-voltage threshold VUVLO, it stops the low-voltage malfunction prevention process and resumes operation of the isolated power supply 80.

[0173] The abnormality detection circuit 87a is configured to be able to operate by supplying the fourth voltage V4r of the fourth low-voltage power supply circuit 66. When the abnormality detection circuit 87a determines that the logic of the abnormality notification signal FMCU is H, the switch 87b is set to the off state. In this case, the voltage Vjin is determined to be above the low voltage threshold value VUVLO. On the other hand, when the abnormality detection circuit 87a determines that the logic of the abnormality notification signal FMCU is L, the switch 87b is set to the on state. In this case, the voltage Vjin is determined to be less than the low voltage threshold value VUVLO, and a low voltage malfunction prevention process is implemented. When this process is implemented, the insulating power supply 80 stops, and the upper arm drive voltage VdH and the lower arm drive voltage VdL begin to gradually decrease to 0V.

[0174] In this embodiment, even if an abnormality occurs within the control circuit 50, which would have been in a shutdown state as in the past, three-phase short-circuit control can be performed. The shutdown state refers to the disconnection of the upper arm switch SWH and the lower arm switch SWL corresponding to the three phases. Here, abnormalities within the control circuit 50 include: an abnormality in the microcomputer 60; an abnormality in at least one of the intermediate power supply circuit 62 and the first to third low-voltage power supply circuits 63 to 65; an abnormality in which switching commands cannot be properly transmitted from the microcomputer 60 to the upper arm driver 81 and the lower arm driver 82; and an abnormality in which voltage cannot be output from the isolated power supply 80. Abnormalities that prevent voltage output from the isolated power supply 80 include abnormalities in the isolated power supply 80 and abnormalities in which power cannot be supplied from the low-voltage power supply 31 to the isolated power supply 80. Here, the abnormality in which power cannot be supplied from the low-voltage power supply 31 to the isolated power supply 80 occurs, for example, due to a disconnection in the electrical path from the low-voltage power supply 31 to the isolated power supply 80, such as the input circuit 61. Furthermore, using the lower arm driver 82 as an example, an abnormality that prevents normal transmission of a switch command includes a disconnection of a signal path from the microcomputer 60 to the lower arm insulating transmission unit 82b.

[0175] use Figure 12 , the three-phase short-circuit control executed when an abnormality occurs in the control circuit 50 is described.

[0176] In step S40, the abnormality detection circuit 87a of the power supply stop unit 87 determines whether the logic level of the input abnormality notification signal FMCU is low. If the logic level of the second determination signal Sg2 output from the microcomputer 60 is low, or if the logic level of the first determination signal Sg1 output from the monitoring unit 85 is high, the logic level of the abnormality notification signal FMCU is low. If an abnormality occurs in the intermediate power supply circuit 62 or the first to third low-voltage power supply circuits 63 to 65 that power the microcomputer 60, the logic level of the second determination signal Sg2 output from the microcomputer 60 is also low. In this embodiment, the abnormality notification signal FMCU corresponds to a "regeneration prevention command."

[0177] Abnormality detection circuit 87a switches switch 87b to the on state when determining that the logic of abnormality notification signal FMCU is L. As a result, determination voltage Vjin input to the UVLO terminal of isolated power supply 80 decreases toward 0V, which is the ground potential.

[0178] In step S41, the power supply control unit of the isolated power supply 80 waits until the voltage Vjin is determined to be lower than the low-voltage threshold VUVLO. If the power supply control unit determines that the voltage Vjin is lower than the low-voltage threshold VUVLO, in step S42, the power supply control unit performs low-voltage malfunction prevention processing and shuts down the isolated power supply 80. As a result, the upper-arm drive voltage VdH and the lower-arm drive voltage VdL output from the isolated power supply 80 begin to decrease toward 0V.

[0179] In step S43, the high-side ASC command unit 91 detects the lower-arm drive voltage VdL output from the isolated power supply 80. After the detected lower-arm drive voltage VdL begins to decrease, the abnormality switch 103 is switched on. This starts supplying the abnormality drive voltage Veps directly from the abnormality power supply 90 to the gates of the lower-arm switches SWL via the abnormality switch 103, the common path 104, and the second limiting diode 105.

[0180] Specifically, the high-side ASC command unit 91 switches the abnormality switch 103 to the on state after a sufficient period of time has passed since the detected lower arm drive voltage VdL starts to decrease and until the upper arm switch SWH turns off. This is to prevent a short circuit between the upper and lower arms.

[0181] For example, the high-side ASC command unit 91 may switch the abnormality switch 103 to the on state if it determines that the detected lower-arm drive voltage VdL has fallen below the predetermined voltage Vp after the detected lower-arm drive voltage VdL begins to decrease. The predetermined voltage Vp is set to a value sufficient to determine that a sufficient period has elapsed before the upper-arm switch SWH turns off, and may be, for example, the same as or less than the threshold voltage Vth.

[0182] Alternatively, for example, the high-side ASC command unit 91 may switch the abnormality switch 103 to the on state when a predetermined period has elapsed since the detected lower-arm drive voltage VdL began to decrease. Here, the predetermined period may be set to a value sufficient to determine that a sufficient period has elapsed before the upper-arm switch SWH has been turned off.

[0183] By switching abnormality switch 103 to the on state, lower arm switch SWL corresponding to phase 3 is turned on. That is, lower arm switch SWL, which is the on-side switch corresponding to phase 3, is turned on. Furthermore, due to the decrease in upper arm drive voltage VdH supplied to upper arm drive unit 81a, upper arm switch SWH, which is the off-side switch corresponding to phase 3, is turned off. As a result, three-phase short-circuit control is executed in step S44.

[0184] use Figure 13 ,right Figure 12 The processing is further explained. Figure 13 (a) shows the change of whether the microcomputer 60 has abnormality or not. Figure 13 (b) shows the transition of the first determination signal Sg1 output from the monitoring unit 85. Figure 13 (c) shows the transition of the abnormality notification signal FMCU. Figure 13 (d) shows the transition of the operating state of the isolated power supply 80 . Figure 13 (e) and (f) show the transition of the upper arm drive voltage VdH and the lower arm drive voltage VdL output from the isolated power supply 80. Figure 13 (g) shows the transition of the driving state of the abnormal switch 103. Figure 13 (h) shows the change of the driving state of the lower arm switch SWL of each phase. Figure 13 (i) shows the transition of the abnormal driving voltage Veps of the abnormal power supply 90 .

[0185] At time t1, an abnormality occurs in microcomputer 60. Consequently, at time t2, the logic of first determination signal Sg1 output from monitoring unit 85 is inverted to H, and at time t3, the logic of abnormality notification signal FMCU is inverted to L. As a result, switch 87b is switched on, and low-voltage malfunction prevention processing is executed for isolated power supply 80. Consequently, at time t4, isolated power supply 80 stops, and upper-arm drive voltage VdH and lower-arm drive voltage VdL begin to decrease.

[0186] After the lower arm drive voltage VdL starts to decrease, at time t5, which is a sufficient period from time t4 until the upper arm switch SWH turns off, the high-side ASC command unit 91 switches the abnormality switch 103 to the on state. Figure 13 During the time period shown, the abnormal drive voltage Veps is controlled to the target voltage. Therefore, by switching the abnormal switch 103 to the on state, power begins to be supplied from the abnormal power supply 90 to the gate of each lower arm switch SWL. Therefore, at time t6, the corresponding lower arm switch SWL is turned on. As described above, whether a sufficient period has elapsed can be determined by, for example, whether the detected lower arm drive voltage VdL is lower than the specified voltage Vp or whether a specified period has elapsed since the lower arm drive voltage VdL began to decrease.

[0187] Furthermore, if an abnormality occurs in low-voltage power supply 31, input circuit 61, the power supply path electrically connecting low-voltage power supply 31 to control circuit 50 is disconnected, or isolated power supply 80 experiences an abnormality, three-phase short-circuit control is executed through the processing of steps S41 to S44. Specifically, in this case, the low-voltage malfunction prevention process stops isolated power supply 80, lowers upper-arm drive voltage VdH and lower-arm drive voltage VdL toward 0V, and performs three-phase short-circuit control.

[0188] Furthermore, three-phase short-circuit control is also implemented in the event of an overvoltage abnormality. Specifically, state determination unit 79 determines whether an overvoltage signal has been input from overvoltage detection unit 78. If state determination unit 79 determines that an overvoltage signal has been input, it outputs a low-voltage ASC command CmdASC to low-voltage ASC command unit 84.

[0189] Upon receiving the low-voltage ASC command CmdASC, the low-voltage ASC command unit 84 outputs a shutdown command CmdSDN. This shutdown command CmdSDN forcibly sets the switching command input to the corresponding upper arm driver 81 to an OFF command, regardless of the switching command output from the microcomputer 60. Furthermore, the low-voltage ASC command unit 84 forcibly sets the switching command input to the corresponding lower arm driver 82 to an ON command, regardless of the switching command output from the microcomputer 60. This executes three-phase short-circuit control.

[0190] Return to previous Figure 9 As described above, the control circuit 50 includes a discharge processing unit 110. Discharge processing unit 110 is provided in a high-voltage region of the control circuit 50 and is configured to execute discharge control of the smoothing capacitor 24 by driving the discharge switch 29. Discharge processing unit 110 controls the discharge of the smoothing capacitor 24 when it determines that a discharge command CmdAD has been input from the microcomputer 60.

[0191] In this embodiment, when the microcomputer 60 determines that an abnormality has occurred in the control system and that power regeneration has occurred, it outputs an on instruction to the lower arm switch SWL corresponding to three and an off instruction to the upper arm switch SWH corresponding to three, and outputs a relay off instruction to the relay controller 45 so that after the lower arm switch SWL corresponding to three becomes on and the upper arm switch SWH corresponding to three becomes off, the first disconnecting switch 23a and the second disconnecting switch 23b are switched to the off state.

[0192] use Figure 14 , the three-phase short-circuit control process and the shutdown control process executed by the microcomputer 60 are described. Figure 14 For convenience, Figure 4 The same processes shown are denoted by the same symbols.

[0193] If a negative determination is made in step S16 , the process proceeds to step S17 a , where an on command is output to the lower arm switch SWL corresponding to number three, and an off command is output to the upper arm switch SWH corresponding to number three.

[0194] Furthermore, in step S17a, a discharge command CmdAD is output to the discharge processing unit 110. This causes the discharge switch 29 to be continuously or intermittently turned on, allowing the discharge resistor 26 to consume the regenerative power generated by the winding 11. As a result, the rise in the terminal voltage of the smoothing capacitor 24 can be suppressed. After completing step S17a, the process proceeds to step S18.

[0195] Furthermore, when the three-phase short-circuit control is executed by the high-voltage-side ASC command unit 91 , the discharge control by the discharge processing unit 110 may also be executed.

[0196] Return to previous Figure 11 As described above, the control circuit 50 includes a filter 46. Filter 46 is located in the low-voltage region of the control circuit 50. When the logic level of the abnormality notification signal FMCU is low, filter 46 is configured to switch the first disconnect switch 23 and the second disconnect switch 23b to the off state after the corresponding lower arm switch SWL is turned on and the corresponding upper arm switch SWH is turned off. Filter 46, for example, is a low-pass filter that delays the abnormality notification signal FMCU output from the OR circuit 86 and outputs it to the relay controller 45. Specifically, filter 46 switches the logic level of the abnormality notification signal FMCU output to the relay controller 45 from high to low at a time delayed by a predetermined time from the time the logic level of the abnormality notification signal FMCU output from the OR circuit 86 switches from high to low. If the relay controller 45 determines that the logic level of the input abnormality notification signal FMCU has switched to low, it outputs a relay disconnect command. Incidentally, in this embodiment, the microcomputer 60, monitoring unit 85, OR circuit 86, relay controller 45, and filter 46 constitute the "abnormality control unit."

[0197] Next, use Figure 15 , describes the inspection process for determining whether the three-phase short-circuit control and the switching of the first disconnect switch 23a and the second disconnect switch 23b to the disconnect state can be performed in sequence. This process is executed by the microcomputer 60. Figure 15 For convenience, Figure 6 The same processes shown are denoted by the same symbols.

[0198] In steps S20 to S28 , the same processing as that described in the first embodiment is performed.

[0199] If the process in step S28 is completed, or if a positive determination is made in step S27, the process proceeds to step S30. In step S30, a precharge command is output to the relay controller 45. This causes charge to be supplied from the high-voltage power supply 30 to the smoothing capacitor 24, increasing the terminal voltage of the smoothing capacitor 24. In this embodiment, the precharge process is performed until the terminal voltage of the smoothing capacitor 24 reaches a value close to the terminal voltage of the high-voltage power supply 30.

[0200] Next, in steps S31 to S36 , a simulation is performed for the case where the logic of the abnormality notification signal FMCU is L, to determine whether the three-phase short-circuit control and the switching of the first disconnecting switch 23 a and the second disconnecting switch 23 b to the open state can be sequentially executed.

[0201] Specifically, in step S31, as a simulation of the process executed when it is determined that an abnormality has occurred in the control system, the logic of the abnormality notification signal FMCU is switched to L. This process can be, for example, a process in which the microcomputer 60 switches the logic of the second determination signal Sg2 to L, or a process in which the microcomputer 60 instructs the monitoring unit 85 to switch the logic of the first determination signal Sg1 output by the monitoring unit 85 to H. Incidentally, in this embodiment, the power supply stop unit 87, the isolated power supply 80, the high-side ASC command unit 91, the abnormality switch 103, and the common path 104 correspond to the "regeneration prevention unit."

[0202] Next, in step S32, a check is performed to determine whether the lower arm switch SWL corresponding to phase 3 is turned on and the upper arm switch SWH corresponding to phase 3 is turned off, as determined by the processing in step S31. The check method in step S23 can be, for example, the check method described in step S23 of the first embodiment. In step S32, if it is determined that the lower arm switch SWL corresponding to phase 3 is turned on and the upper arm switch SWH corresponding to phase 3 is turned off, it is determined that three-phase short-circuit control is being performed normally.

[0203] Next, in step S33, the discharge process is performed in the same manner as in step S25. Next, in step S34, a check is performed to verify that the first and second disconnect switches 23a and 23b have been switched to the OFF state by the process in step S31. The inspection method in step S34 can be, for example, the inspection method described in step S26 of the first embodiment.

[0204] Next, in step S35, a determination is made as to whether all conditions A through C are satisfied. Condition A is the condition for determining in step S32 that three-phase short-circuit control can be normally executed. Condition B is the condition for determining in step S34 that first and second disconnect switches 23a, 23b can be switched to the OFF state. Condition C is the condition for switching first and second disconnect switches 23a, 23b to the OFF state after three-phase short-circuit control is executed. For example, the determination of whether condition C is satisfied can be made based on the determination results of steps S32 and S34.

[0205] If it is determined in step S35 that at least one of conditions A through C does not hold, at least one of the following has occurred: an abnormality preventing normal execution of three-phase short-circuit control; an abnormality preventing the first and second disconnect switches 23a, 23b from being switched to the open state; or an abnormality preventing the sequential execution of three-phase short-circuit control and the switching of the first and second disconnect switches 23a, 23b to the open state. In this case, in step S36, information indicating the occurrence of the abnormality is stored in memory 60a. The process then transitions to step S29. Alternatively, in step S36, a process may be performed to notify the user of the abnormality. Incidentally, in this embodiment, the process in step S31 corresponds to the "processing unit," the processes in steps S32, S34, and S35 correspond to the "inspection unit," and the process in step S33 corresponds to the "discharge processing unit."

[0206] If it is determined in step S35 that all conditions A to C are satisfied, it is determined that the three-phase short-circuit control and the switching of the first disconnector 23a and the second disconnector 23b to the OFF state can be normally performed in sequence.

[0207] According to the present embodiment described above, even when it is determined that an abnormality has occurred in the control system, the first disconnector 23a and the second disconnector 23b can be switched to the open state after the three-phase short-circuit control is executed.

[0208] <Modification of Second Embodiment>

[0209] In the configuration for switching the first disconnect switch 23 and the second disconnect switch 23b to the OFF state after the lower arm switch SWL corresponding to the third is turned on and the upper arm switch SWH corresponding to the third is turned off when the logic level of the abnormality notification signal FMCU is L, the filter 46 is not essential.

[0210] For example, a configuration may be employed in which a signal path connecting the OR circuit 86 to the abnormality detection circuit 87a and a signal path connecting the OR circuit 86 to the relay controller 45 are separately provided as the signal path of the abnormality notification signal FMCU output from the OR circuit 86. In this configuration, the OR circuit 86 switches the logic of the abnormality notification signal FMCU output to the abnormality detection circuit 87a to L and then switches the logic of the abnormality notification signal FMCU output to the relay controller 45 to L.

[0211] Alternatively, for example, a configuration may be employed in which a common signal path is provided for transmitting the abnormality notification signal FMCU output from the OR circuit 86, and signal paths branching from the signal path and connected to the abnormality detection circuit 87a and the relay controller 45, respectively. In this configuration, if a capacitor is provided for supplying power to the relay controller 45, the capacitance of the capacitor may be determined such that, after the logic level of the abnormality notification signal FMCU transmitted to the abnormality detection circuit 87a switches to L, the logic level of the abnormality notification signal FMCU transmitted to the relay controller 45 switches to L.

[0212] ·exist Figure 15 In steps S25 and S33, the discharge of the smoothing capacitor 24 may be promoted by executing at least one of a process of causing the switching device unit 20 to flow current through the winding 11, a process of driving the electrical device 25, and a process of turning on the discharge switch 29.

[0213] The discharge processing unit 110 may not be included in the control circuit 50 .

[0214] · It is also possible to configure each of the cut-off switches 23a, 23b to have a function of monitoring its own driving state and transmit the monitored driving state to the microcomputer 60. In this case, instead of Figure 5 In the processing of steps S25 and S26 and the processing of steps S33 and S34, the microcomputer 60 may also execute processing for determining that each of the disconnect switches 23a and 23b is switched to the OFF state when it is determined that the monitored driving state is the OFF state.

[0215] ·exist Figure 15 In the illustrated process, after the process group of steps S31 to S26 is executed, the process group of steps S20 to S28 may be executed via step S30 .

[0216] ·exist Figure 15In the illustrated process, it is not necessary to execute both the processing group of steps S20 to S28 and the processing group of steps S31 to S26 in one end sequence. For example, the processing group of steps S20 to S28 and the processing group of steps S31 to S26 may be executed alternately for each end sequence.

[0217] Instead of the lower arm drive voltage VdL, the high-side ASC command unit 91 may switch the abnormality switch 103 to the OFF state based on the upper arm drive voltage VdH. In this case, the high-side ASC command unit 91 may obtain information on the upper arm drive voltage VdH via the insulating transmission unit.

[0218] The power supply control units that comprise isolated power supply 80 may be provided separately for the upper and lower arm isolated power supplies. In this case, the low-voltage malfunction prevention process can be used to shut down both the power supply control units corresponding to the upper and lower arm isolated power supplies, thereby shutting down isolated power supply 80.

[0219] As the three-phase short-circuit control executed by the high-voltage-side ASC command unit 91, control can also be performed by turning on the three corresponding upper arm switches SWH and turning off the three corresponding lower arm switches SWL. In this case, the abnormal power supply 90 can be provided separately for each of the three corresponding upper arm drive units 81a.

[0220] <Third embodiment>

[0221] Hereinafter, referring to the accompanying drawings, the third embodiment will be described focusing on the differences from the first embodiment. Figure 16 As shown, the control system includes a switch 34. In addition, Figure 16 For convenience, the previous Figure 1 The same structures are denoted by the same symbols.

[0222] The changeover switch 34 is provided in a conductive path (for example, a bus bar) that connects a connection point between the upper arm switch SWH and the lower arm switch SWL of each phase and the first end of the winding 11 of each phase.

[0223] The microcomputer 60 performs switching control to output an OFF command or an ON command to the selector switch 34 for each phase. This switches the selector switch 34 for each phase into the OFF state or the ON state. Incidentally, in this embodiment, the processing of the microcomputer 60 that outputs an OFF command or an ON command to the selector switch 34 corresponds to the "regeneration prevention unit."

[0224] use Figure 17 , the processing performed by the microcomputer 60 is described. Figure 17 For convenience, Figure 4 The same processes shown are denoted by the same symbols.

[0225] If it is determined in step S10 that no abnormality has occurred, the process proceeds to step S11 and normal control is performed. In the present embodiment, when normal control is performed, the selector switch 34 of each phase is turned on.

[0226] If it is determined in step S10 that an abnormality has occurred, the process proceeds to step S12. If it is determined in step S12 that power regeneration has occurred, the process proceeds to step S16b. In step S16b, it is determined whether an opening command is being output to the switching switches 34 of each phase.

[0227] If it is determined in step S16b that an OFF command is being output to the selector switches 34 for each phase, the process proceeds to step S14. On the other hand, if it is determined in step S16b that an ON command is being output to the selector switches 34 for each phase, the process proceeds to step S17b. In step S17b, an OFF command (equivalent to a "switching control execution command") is output to the selector switches 34 for each phase. After executing step S17b, a positive determination is made in the next step S16b. After completing step S17b, the process proceeds to step S18.

[0228] according to Figure 17 In the process shown, after the selector switches 34 for each phase are switched to the OFF state, the first and second disconnect switches 23a and 23b are switched to the OFF state. This prevents the terminal voltage of the smoothing capacitor 24 from rising sharply when an abnormality occurs in the control system and power regeneration is likely to occur.

[0229] Next, use Figure 18 , explaining the process of checking whether the switching switch 34 can be switched to the OFF state and the switching of the first disconnect switch 23a and the second disconnect switch 23b to the OFF state can be performed in sequence. This process is executed by the microcomputer 60. Figure 18 For convenience, Figure 6 The same processes shown are denoted by the same symbols.

[0230] In step S22b, a process is executed to simulate the process to be executed when it is determined that an abnormality has occurred in the control system. Specifically, an opening command is output to the selector switch 34 of each phase.

[0231] In step S23b, the switch 34 for each phase is checked to determine whether it is in the open state based on the processing in step S22b. For example, if the switch 34 is a voltage-controlled semiconductor switching element, the switch 34 may be determined to be in the open state if the gate voltage of the switch 34 is determined to be below the open determination voltage. Alternatively, if the switch 34 is a relay with a drive state monitoring function, the switch 34 may be determined to be in the open state based on the monitored drive state. After the processing in step S23b is completed, the process proceeds to step S24.

[0232] In step S27b, a determination is made as to whether all six to eight conditions are met. The sixth condition is determined in step S23b to be capable of switching the selector switches 34 for each phase to the OFF state. The seventh condition is the same as the second condition described above. The eighth condition is determined to be the same as the first and second disconnect switches 23a and 23b after the selector switches 34 are switched to the OFF state. For example, the determination of whether the eighth condition is met can be made based on the determination results of steps S23b and S26.

[0233] According to the present embodiment described above, the same effects as those of the first embodiment can be obtained.

[0234] <Modification of the Third Embodiment>

[0235] ·exist Figure 17 In the process of , the process of steps S12 and S13 may not be performed. In this case, if a positive determination is made in step S10, the process proceeds to step S16b. This is based on the assumption that switching the switch 34 to the off state can play the same role as the shutdown control.

[0236] Instead of switching all three-phase selectors 34 , only two corresponding selectors 34 may be switched to the OFF state.

[0237] The switch 34 included in the control system may correspond to two rather than three.

[0238] <Fourth embodiment>

[0239] Hereinafter, referring to the accompanying drawings, the fourth embodiment will be described focusing on the differences from the first embodiment. Figure 19 The vehicle 200 (equivalent to the "mobile body") shown in FIG. 1 is equipped with a control system. Figure 19 For convenience, Figure 1 The same structures or corresponding structures shown in the figures are denoted by the same symbols.

[0240] Vehicle 200 includes a control system with one electric motor and two clutches. As a driving power source, vehicle 200 includes an internal combustion engine 210 in addition to a rotating electric machine 10. Furthermore, vehicle 200 includes a first clutch 211, a second clutch 212, a transmission 213, a differential 214, and wheels 220. Transmission 213 is, for example, a CVT.

[0241] The output shaft 210a (e.g., a crankshaft) of the internal combustion engine 210 is connected to the rotating shaft 10a, which constitutes the rotor of the rotating electric machine 10, via a first clutch 211. Control of the first clutch 211 switches the power transmission state between the output shaft 210a, which serves as the drive shaft, and the rotating shaft 10a to either a power transmission state or a power disconnection state. The first clutch 211 is controlled by a higher-level ECU (not shown) included in the vehicle 200.

[0242] The first rotating shaft 213a of the speed change device 213 is connected to the rotating shaft 10a via the second clutch 212. In the speed change device 213, the ratio of the rotational speed of the first rotating shaft 213a to the rotational speed of the second rotating shaft 213b, i.e., the speed ratio, is controlled to a target speed ratio. By controlling the second clutch 212, the first rotating shaft 213a, which serves as the drive shaft, and the rotating shaft 10a of the rotating electric machine 10 are switched to either a power transmission state or a power disconnection state. The second clutch 212 is controlled by a higher-level ECU. In this embodiment, the microcomputer 60 constituting the control circuit 50 can instruct the higher-level ECU to control the first clutch 211 and the second clutch 212.

[0243] In the present embodiment, the processing of the microcomputer 60 that controls the first clutch 211 and the second clutch 212 corresponds to a "regeneration prevention unit."

[0244] use Figure 20 , the processing performed by the microcomputer 60 is described. Figure 20 For convenience, Figure 4 The same processes shown are denoted by the same symbols.

[0245] If it is determined in step S10 that no abnormality has occurred, the process proceeds to step S11, and normal control is performed. In this embodiment, during normal control, when only the rotating electric machine 10 of the internal combustion engine 210 is used as the driving power source, control is performed such that, for example, the second clutch 212 is in the power transmission state and the first clutch 211 is in the power interruption state. Furthermore, during normal control, when both the rotating electric machine 10 and the internal combustion engine 210 are used as the driving power source, control is performed such that both the first clutch 211 and the second clutch 212 are in the power transmission state.

[0246] If an abnormality is determined to have occurred in step S10, the process proceeds to step S12. If power regeneration is determined to have occurred in step S12, the process proceeds to step S16c. In step S16c, it is determined whether the first clutch 211 and the second clutch 212 are being controlled to be in the power cutoff state.

[0247] If it is determined in step S16c that the first clutch 211 and the second clutch 212 are controlled to be in the power-off state, the process proceeds to step S14. On the other hand, if it is determined in step S16c that the first clutch 211 and the second clutch 212 are controlled to at least set the second clutch 212 to the power-transmitting state, the process proceeds to step S17c. In step S17c, a command is output to the higher-level ECU indicating that the first clutch 211 and the second clutch 212 are controlled to switch to the power-off state. In this embodiment, this process is equivalent to outputting a "clutch control execution command." While in the power-off state, since power is not supplied to the rotating shaft 10a, the rotational speed of the rotor gradually decreases. As a result, the occurrence of power regeneration can be prevented. After executing step S17c, a positive determination is made in the next step S16c. After completing step S17c, the process proceeds to step S18.

[0248] according to Figure 20 In the process shown, after the first clutch 211 and the second clutch 212 are in the power-off state and no power regeneration occurs, the first disconnect switch 23a and the second disconnect switch 23b are switched to the open state. This prevents a sudden increase in the terminal voltage of the smoothing capacitor 24 in the event of a control system abnormality and the possibility of power regeneration.

[0249] Next, use Figure 21 , explaining the process of checking whether the switching to the power cut-off state by the first clutch 211 and the second clutch 212 and the switching to the disconnected state by the first cut-off switch 23a and the second cut-off switch 23b can be executed in sequence. This process is executed by the microcomputer 60. Figure 21 For convenience, Figure 6 The same processes shown are denoted by the same symbols.

[0250] In step S22c, a process is executed to simulate the process executed when it is determined that an abnormality has occurred in the control system. Specifically, a command is output to the upper ECU to control the first clutch 211 and the second clutch 212 to switch to the power cutoff state.

[0251] In step S23c, the first clutch 211 and the second clutch 212 are checked to determine whether they have entered the power-off state as a result of the processing in step S22c. For example, if the rotational speed of the rotating shaft 10a is determined to be lower than the rotational speed of the first rotating shaft 213a by a predetermined rotational speed or more, then the first clutch 211 and the second clutch 212 may be determined to have entered the power-off state. After the processing in step S23c is completed, the process proceeds to step S24.

[0252] In step S27c, a determination is made as to whether all of the ninth to eleventh conditions are met. The ninth condition is determined in step S23c to be capable of switching to the power-off state. The tenth condition is the same as the second condition described above. The eleventh condition is determined to be the condition that, after switching to the power-off state, the first and second disconnect switches 23a and 23b are switched to the OFF state. For example, the determination of whether the eleventh condition is met can be made based on the determination results of steps S23c and S26.

[0253] According to the present embodiment described above, the same effects as those of the first embodiment can be obtained.

[0254] <Other Implementation Methods>

[0255] Furthermore, the above-described embodiments may be implemented with the following modifications.

[0256] The mobile object is not limited to a vehicle, for example Figure 22 As shown, it can also be an aircraft 300 including a rotating motor as a flight power source. Figure 22 For convenience, the previous Figure 19 The same structures or corresponding structures shown in the figures are denoted by the same symbols.

[0257] The aircraft 300 includes a rotating electrical machine 10, an inverter 15, a high voltage power supply 30, a clutch 310, a drive shaft 310a, and a propeller 320. Figure 22 In the figure, the first disconnect switch 23a, the second disconnect switch 23b, etc. are omitted.

[0258] The drive shaft 310a is connected to the rotating shaft 10a of the rotating electric machine 10 via the clutch 310, and the propeller 320 is connected to the drive shaft 310a. By controlling the clutch 310, the drive shaft 310a and the rotating shaft 10a are switched to either a power transmission state or a power disconnection state. By being in the power transmission state, the drive shaft 310a rotates to cause the aircraft 300 to fly. The microcomputer 60 that constitutes the control circuit 50 can instruct the higher-level ECU to control the clutch 310.

[0259] For the aircraft 300 described above, the same Figure 20 and Figure 21 Same treatment.

[0260] In addition, the mobile body is not limited to an aircraft, and may be a ship, for example. In this case, refer to the previous Figure 22 The rotating motor 10 becomes the power source for sailing of the ship. The driving shaft 310a is connected to the screw and rotates to make the ship sail.

[0261] The second cutoff switch 23b may not be provided.

[0262] The first disconnect switch 23a may not be provided. In this case, a series connection of the precharge switch 23p and the precharge resistor 27 may be connected in parallel with the second disconnect switch 23b.

[0263] The first disconnecting switch 23 a , the second disconnecting switch 23 b , and the precharge switch 23 p may also be included in the inverter 15 .

[0264] The relay controller 45 may be provided outside the inverter 15 in the control system. In this case, for example, a configuration may be employed in which instructions are transmitted from the microcomputer 60 to the relay controller 45 via communication or the like. Furthermore, in this case, instructions may be transmitted from the microcomputer 60 to the relay controller 45 via an ECU external to the inverter 15, such as a higher-level ECU.

[0265] The first disconnect switch 23 a , the second disconnect switch 23 b , and the precharge switch 23 p are not limited to relays, and may be, for example, semiconductor switching elements.

[0266] As the actuators 81 and 82 , actuators that do not straddle the boundary between the low-pressure region and the high-pressure region and are provided only in the high-pressure region may be used.

[0267] In the previous Figure 1 In the illustrated configuration, a boost converter may be included between the smoothing capacitor 24 and the switches 23 a , 23 b , and 23 p .

[0268] The switch constituting the switching device portion is not limited to an IGBT, and may be, for example, an N-channel MOSFET having a built-in body diode.

[0269] The switches in each phase and each arm of the switching device section may be two or more switches connected in parallel. In this case, the combination of switches connected in parallel may include, for example, a combination of a SiC switching element and a Si switching element, or a combination of an IGBT and a MOSFET.

[0270] The controlled variable of the rotating electrical machine is not limited to the torque, and may be, for example, the rotational speed of the rotor of the rotating electrical machine.

[0271] The rotating electrical machine is not limited to having a single winding set and may include multiple winding sets. For example, if it has two winding sets, the rotating electrical machine is a six-phase rotating electrical machine. Alternatively, the rotating electrical machine may be a nine-phase rotating electrical machine, for example.

[0272] The rotating electrical machine is not limited to a permanent magnet synchronous machine; for example, a winding-excitation synchronous machine may be used. Furthermore, the rotating electrical machine is not limited to a synchronous machine; for example, an induction machine may be used. For example, when a winding-excitation synchronous machine is used as the rotating electrical machine, a process for preventing the occurrence of power regeneration may be performed, for example, by reducing the excitation current flowing through the field winding provided on the rotor to a predetermined current to reduce the magnetic flux. Here, the predetermined current can be set to, for example, 0 A or a value greater than 0 A.

[0273] The rotary electric machine is not limited to being used as an in-vehicle main machine, but can also be used for other applications such as electric motors constituting electric power steering systems and electric compressors for air conditioners.

[0274] The control unit and method thereof described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor and a memory, and the above-mentioned processor is programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and method thereof described in the present disclosure may be implemented by a special-purpose computer, which is provided by constituting a processor by one or more special-purpose hardware logic circuits. Alternatively, the control unit and method thereof described in the present disclosure may be implemented by one or more special-purpose computers, which are constituted by a combination of a processor and a memory programmed to execute one or more functions and a processor constituted by one or more hardware logic circuits. In addition, the computer program may also be stored in a computer-readable non-transitory tangible storage medium as an instruction executed by a computer.

[0275] Although the present disclosure is described based on embodiments, it should be understood that the present disclosure is not limited to the above-described embodiments and structures. The present disclosure also includes various modifications and variations within the scope of equivalents. In addition, various combinations and methods, and further combinations and methods that include only one element, or more or less than the above elements, also fall within the scope and concept of the present disclosure.

Claims

1. A control circuit for a power converter, wherein the control circuit for the power converter is applicable to a system, the system comprising: Rotating electric machines; a power converter having upper and lower arm switches electrically connected to windings of respective phases of the rotating electrical machine; power supply; a disconnect switch disposed in an electrical path connecting the power source to the power converter; as well as a power storage unit connected to a side of the electrical path opposite to the power supply with respect to the disconnect switch, The control circuit of the power converter comprises: a switch command generating unit that performs normal control, in which a switch command is generated and output to the switches of the upper and lower arms so as to control the control amount of the rotating electric machine to a command value; an abnormality determination unit configured to determine whether an abnormality has occurred in the system; a regeneration prevention unit that prevents occurrence of electric power regeneration, which causes current to flow from the rotating electric machine side toward the power storage unit; and an abnormality control unit, which, when the abnormality determination unit determines that an abnormality has occurred during the execution of the normal control, outputs a regeneration prevention instruction to the regeneration prevention unit and outputs a switch-off instruction to the disconnect switch to switch the disconnect switch to an open state after the regeneration prevention unit has prevented the occurrence of the power regeneration, After the abnormality control unit outputs a regeneration prevention instruction to the regeneration prevention unit and a switch-off instruction to the disconnect switch, if the abnormality determination unit determines that no abnormality has occurred, the abnormality control unit outputs a switch-on instruction to the disconnect switch. In a state where the disconnect switch is turned on by the switch-on command, the normal control is resumed by the switch-on command generating unit.

2. The control circuit of the power converter according to claim 1, wherein: The regeneration prevention unit performs short-circuit control to turn on the switch of one of the upper and lower arms, i.e., the on-side switch, and turns off the switch of the other arm, i.e., the off-side switch. The abnormality control unit outputs the execution instruction of the short-circuit control as the regeneration prevention instruction to the regeneration prevention unit, and outputs the switch disconnection instruction to the disconnection switch in a manner that switches the disconnection switch to the disconnection state after setting the on-side switch to the on-state and the off-side switch to the off-state.

3. The control circuit of the power converter according to claim 1, wherein: The system is installed on a mobile body. The system includes a clutch that switches between a drive shaft that rotates to move the movable body and a rotating shaft of the rotating motor to either a power transmission state or a power cutoff state. The regeneration prevention unit controls the clutch to switch the power supply between the drive shaft and the rotating shaft to a power cutoff state. The abnormal control unit outputs an execution instruction for controlling the clutch as the regeneration prevention instruction to the regeneration prevention unit, and outputs the switch disconnection instruction to the disconnection switch, by switching the disconnection switch to the disconnected state after switching the power disconnection state between the drive shaft and the rotating shaft.

4. The control circuit of the power converter according to claim 1, wherein: The system includes a switch provided in a conductive path connecting a connection point of the switches of the upper and lower arms with the winding, The regeneration prevention unit performs switching control to switch the switch to an OFF state. The abnormality control unit outputs the switching control execution instruction to the regeneration prevention unit as the regeneration prevention instruction, and outputs the switch opening instruction to the disconnect switch so as to switch the disconnect switch to the open state after switching the changeover switch to the open state.

5. A control circuit for a power converter, wherein the control circuit for the power converter is applicable to a system, the system comprising: Rotating electric machines; a power converter electrically connected to the windings of the rotating electrical machine; power supply; a disconnect switch disposed in an electrical path connecting the power source to the power converter; as well as a power storage unit connected to a side of the electrical path opposite to the power supply with respect to the disconnect switch, The control circuit of the power converter comprises: an abnormality determination unit configured to determine whether an abnormality has occurred in the system; a regeneration prevention unit that prevents occurrence of electric power regeneration, the occurrence of which causes current to flow from the rotating electric machine side toward the power storage unit; an abnormality control unit that, when the abnormality determination unit determines that an abnormality has occurred, outputs a regeneration prevention instruction to the regeneration prevention unit and outputs a switch-off instruction to the disconnect switch to switch the disconnect switch to an open state after the regeneration prevention unit has prevented the occurrence of power regeneration; and a safe state determination unit that determines whether the power regeneration occurs when the abnormality determination unit determines that an abnormality has occurred, When the safe state determination unit determines that the electric power regeneration has occurred, the abnormality control unit outputs the regeneration prevention instruction to the regeneration prevention unit and outputs the switch opening instruction to the disconnect switch. When the safe state determination unit determines that the electric power regeneration is not occurring, a switch-on command is output to the disconnect switch.

6. The control circuit of the power converter according to any one of claims 1 to 5, wherein: The control circuit of the power converter comprises: a processing unit that causes the abnormality control unit to simulate a process to be executed when it is determined that an abnormality has occurred in the system; and A check unit determines whether the disconnect switch can be switched to an OFF state after the abnormal-time control unit prevents the occurrence of the electric power regeneration by causing the abnormal-time control unit to perform a simulation.

7. The control circuit of the power converter according to claim 6, wherein: The control circuit of the power converter includes a discharge processing unit that performs a discharge process of the power storage unit after outputting the switch-off instruction to the disconnect switch. The inspection unit determines that the disconnect switch is switched to the OFF state by the switch OFF instruction based on the fact that the voltage of the power storage unit is reduced by execution of the discharge process.

8. The control circuit of the power converter according to claim 7, wherein: The discharge processing unit performs the discharge processing when a stop instruction of the system is issued. The inspection unit determines that the disconnect switch is switched to the open state by the switch opening instruction based on the fact that the voltage of the power storage unit is reduced by the execution of the discharge process when the system stop instruction is issued.

9. The control circuit of the power converter according to any one of claims 1 to 8, wherein: The system includes a series connection of a discharge resistor and a discharge switch connected in parallel with the power storage unit. The abnormality control unit turns on the discharge switch when the abnormality determination unit determines that an abnormality has occurred.

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