Control circuit of a power converter

Abstract

A control circuit (50) constitutes an in-vehicle system including a multiphase rotary electric machine (11) having a rotor (12) capable of power transmission to a drive wheel (14), and a power converter (20) having upper and lower arm switches (SWH, SWL) electrically connected to each phase winding (13) of the rotary electric machine. The control circuit includes an abnormality determination section (81) that determines whether an abnormality has occurred in the in-vehicle system, and a short-circuit control section (81) that executes short-circuit control that turns on a switch (SWL) of either one of the upper and lower arms and turns off a switch (SWH) of the other arm, as a condition for determining that an abnormality has occurred in a state in which the in-vehicle system is started.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a control circuit of a power converter having upper and lower arms whose switches are connected to windings of phases of a rotary electric machine. BACKGROUND

[0002] As such a control circuit, for example, as described in Patent Literature 1, a control circuit that configures an in-vehicle system including a rotary electric machine of multiple phases and a power converter having upper and lower arms whose switches are electrically connected to windings of phases of the rotary electric machine is known. The control circuit determines whether an abnormality has occurred in the in-vehicle system, and in the case where it is determined that an abnormality has occurred, performs short-circuit control that turns on the switches of one of the arms and turns off the switches of the other arm.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2017-118815 SUMMARY

[0006] However, there is a case where the vehicle is towed so that the rotor of the rotary electric machine that is capable of power transmission to the drive wheels is rotated. In this case, if the short-circuit control is performed, a circulating current flows through a closed circuit including the winding and the turned-on switch due to the counter electromotive force generated in the winding by the rotation of the rotor, and the power converter can possibly become in a state of overheating.

[0007] To solve this problem, for example, it can be conceivable to cause the power converter to include a cooling device and to cool the power converter by the cooling device. However, the cooling device is generally stopped when the vehicle is towed. Therefore, even if the cooling device is included in the power converter, it can be impossible to prevent the power converter from becoming in a state of overheating when the vehicle is towed.

[0008] Therefore, the main object of the present disclosure is to provide a control circuit of a power converter that can prevent the power converter from becoming in a state of overheating when a vehicle is towed.

[0009] The present disclosure is a control circuit of a power converter that constitutes a vehicle-mounted system including a multiphase rotary electric machine having a rotor capable of power transmission to drive wheels, and a power converter having upper and lower arm switches electrically connected to each phase winding of the rotary electric machine, wherein the control circuit of the power converter includes an abnormality determination section that determines whether an abnormality has occurred in the vehicle-mounted system, and a short-circuit control section that executes short-circuit control of turning on the switch of either one of the upper and lower arms, i.e., the on-side switch, and turning off the switch of the other arm, i.e., the off-side switch, on condition that it is determined that the abnormality has occurred in the vehicle-mounted system in a state where the vehicle-mounted system is started.

[0010] In the present disclosure, the short-circuit control is executed on condition that it is determined that an abnormality has occurred in the vehicle-mounted system in a state where the vehicle-mounted system is started. Therefore, the short-circuit control is not executed before the system is started. Since traction of the vehicle is usually performed before the vehicle-mounted system is started, according to the present disclosure, it is possible to prevent the short-circuit control from being executed at the time of traction of the vehicle. As a result, it is possible to prevent the power converter from becoming in an overheated state at the time of traction of the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0011] The above objects, other objects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0012] Figure 1 is a whole configuration diagram of the control system of the first embodiment.

[0013] Figure 2 is a diagram showing the control circuit and its surrounding structure.

[0014] Figure 3 is a diagram showing the upper and lower arm drive sections and their surrounding structure.

[0015] Figure 4 is a flowchart showing the processing steps of determination of the permission / prohibition state of the ASC control.

[0016] Figure 5 is a flowchart showing the processing steps of determination of the execution of the ASC control.

[0017] Figure 6 is a timing chart showing an example of the ASC control.

[0018] Figure 7 is a timing chart showing an example of the control at the time of parking.

[0019] Figure 8 is a timing chart showing an example of the ASC control.

[0020] Figure 9 This is a diagram showing the upper and lower arm drive units and their surrounding structures in the second embodiment.

[0021] Figure 10 This is a diagram showing the upper and lower arm drive units and their surrounding structures in the third embodiment.

[0022] Figure 11 It is a timing diagram that shows the starting method of the power supply in case of an emergency.

[0023] Figure 12 This is a diagram showing the upper and lower arm drive units and their surrounding structures according to the sixth embodiment. Detailed Implementation

[0024] <First Implementation>

[0025] Hereinafter, a first embodiment of the control circuit of this disclosure will be described with reference to the accompanying drawings. The control circuit of this embodiment is applicable to a three-phase inverter as a power converter. In this embodiment, a control system including the control circuit and the inverter is installed in a vehicle such as an electric vehicle or a hybrid vehicle.

[0026] like Figure 1 As shown, the vehicle 10 includes a control system, which includes a rotary motor 11 and an inverter 20. The rotary motor 11 is an on-board host, and its rotor 12 is capable of transmitting power to the drive wheels 14. In this embodiment, a synchronous machine is used as the rotary motor 11, and more specifically, a permanent magnet synchronous machine is used.

[0027] The inverter 20 includes a series connection of upper arm switches SWH and lower arm switches SWL, equivalent to three phases. In each phase, the first end of the winding 13 of the rotating motor 11 is connected to the connection point of the upper arm switches SWH and lower arm switches SWL. The second end of each phase winding 13 is connected at the neutral point. The phase windings 13 are arranged with electrical angles offset from each other by 120°. In this embodiment, voltage-controlled semiconductor switching elements are used as each of the switches SWH and SWL, more specifically, IGBTs are used. Upper arm diodes DH and lower arm diodes DL, which serve as freewheeling diodes, are connected in reverse parallel to the upper arm switches SWH and lower arm switches SWL.

[0028] The positive terminal of the high-voltage power supply 30 is connected to the collector of each upper arm switch SWH (which serves as the high-potential side terminal) via the high-potential side circuit 22H. The negative terminal of the high-voltage power supply 30 is connected to the emitter of each lower arm switch SWL (which serves as the low-potential side terminal) via the low-potential side circuit 22L. In this embodiment, the high-voltage power supply 30 is a secondary battery with an output voltage (rated voltage) of, for example, 100V or higher.

[0029] A first disconnect switch 23a is provided in the high-potential side circuit 22H, and a second disconnect switch 23b is provided in the low-potential side circuit 22L. Each switch 23a and 23b is, for example, a relay or a semiconductor switching element. Here, each switch 23a and 23b can be driven by the control circuit 50 included in the control system, or it can be driven by a higher-level control device relative to the control circuit 50.

[0030] The control system includes a smoothing capacitor 24. The smoothing capacitor 24 electrically connects a portion of the high-potential side circuit 22H that is closer to the inverter 20 side than the first disconnect switch 23a to a portion of the low-potential side circuit 22L that is closer to the inverter 20 side than the second disconnect switch 23b.

[0031] The control system includes on-board electrical equipment 25. Electrical equipment 25 includes, for example, 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 a high-voltage power supply 30 to circulate refrigerant in the on-board refrigeration cycle. The DC-DC converter steps down the output voltage of the high-voltage power supply 30 and supplies it to the on-board 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, such as a lead-acid battery, whose output voltage (rated voltage) is lower than the output voltage (rated voltage) of the high-voltage power supply 30 (e.g., 12V).

[0032] The control system includes a cooling device 40 for cooling the inverter 20. The cooling device 40 is driven, for example, by power supplied from a low-voltage power supply 31. The cooling device 40 includes a cooling water passage for supplying cooling fluid (cooling water) to the components of the inverter 20, such as the upper arm switch SWH and the lower arm switch SWL, and a pump for circulating the cooling water in the cooling water passage. Furthermore, the cooling device 40 is not limited to a liquid-cooled type; for example, it could be an air-cooled type including a fan.

[0033] like Figure 2 As shown, the control system includes a start switch 33. The start switch 33 is, for example, an ignition switch or a push-button start switch, operated by the user of the vehicle 10. When the start switch 33 is turned on, the user instructs the control system to start. Conversely, when the start switch 33 is turned off, the user instructs the control system to stop.

[0034] Next, the structure of the control circuit 50 will be described. The control circuit 50 includes an input circuit 60 and a power supply circuit 61. The positive terminal of the low-voltage power supply 31 is connected to the input circuit 60 via a fuse 32. A ground member, which is a ground site, is connected to the negative terminal of the low-voltage power supply 31. The power supply circuit 61 is supplied with power from the input circuit 60 and generates a second voltage V2. In the present embodiment, the power supply circuit 61 generates the second voltage V2 (for example, 5 V) by stepping down the first voltage VI output from the input circuit 60.

[0035] The control circuit 50 includes a microcomputer 62. The microcomputer 62 includes a CPU and a peripheral circuit other than the CPU. The peripheral circuit includes an input / output section for exchanging signals with the outside. A signal notifying that the start switch 33 is turned on or off is input to the microcomputer 62. In addition, the microcomputer 62 generates switching instructions for each of the switches SWH, SWL of the inverter 20 in order to control the control amount of the rotating electric machine 11 to the command value. The control amount is, for example, torque. In addition, the microcomputer 62 generates a switching instruction in which the upper arm switch SWH and the lower arm switch SWL are alternately turned on in each phase. The input circuit 60 and the power supply circuit 61 are provided in the low-voltage region of the control circuit 50 in addition to the microcomputer 62.

[0036] The control circuit 50 has an insulated power supply 70, an upper arm driver 71, a lower arm driver 72, and a determination signal transmission section 73. In the present embodiment, the upper arm driver 71 is separately provided corresponding to each of the upper arm switches SWH, and the lower arm driver 72 is separately provided corresponding to each of the lower arm switches SWL. Therefore, a total of six drivers 71, 72 are provided.

[0037] The insulated power supply 70 and the upper and lower arm drivers 71, 72 are provided in the low-voltage region and the high-voltage region across the boundary between the low-voltage region and the high-voltage region in the control circuit 50. Specifically, the insulated power supply 70 includes an upper arm insulated power supply separately provided for each of the upper arm drivers 71 of the three phases and a lower arm insulated power supply common to the lower arm drivers 72 of the three phases. Further, the lower arm insulated power supply can also be separately provided for each of the lower arm drivers 72 of the three phases.

[0038] The insulated power supply 70 generates an upper arm drive voltage VdH to be supplied to the upper arm driver 71 and a lower arm drive voltage VdL to be supplied to the lower arm driver 72 based on the first voltage VI supplied from the input circuit 60, and outputs to the high-voltage region.

[0039] Next, the use of the insulated power supply 70 will be described. Figure 3 The upper and lower arm drivers 71, 72 will be described.

[0040] The upper arm actuator 71 includes an upper arm drive unit 71a and an upper arm insulation transmission unit 71b. The upper arm drive unit 71a is located in the high-voltage region. The upper arm insulation transmission unit 71b is located across the boundary between the low-voltage and high-voltage regions. While electrically isolating the low-voltage and high-voltage regions, the upper arm insulation transmission unit 71b transmits switching commands output from the microcomputer 62 to the upper arm drive unit 71a. The upper arm insulation transmission unit 71b is, for example, an optocoupler or a magnetic coupler.

[0041] The upper arm drive section 71a and the upper arm insulation transmission section 71b in the upper arm driver 71 are configured such that they can operate by supplying the upper arm drive voltage VdH to the insulating power supply 70. The upper arm insulation transmission section 71b in the upper arm driver 71 is configured such that it can operate by supplying the second voltage V2 to the power supply circuit 61.

[0042] When the switching command input via the upper arm insulation transfer unit 71b is an on command, the upper arm drive unit 71a supplies charging current to the gate of the upper arm switch SWH. As a result, the gate voltage of the upper arm switch SWH becomes above the threshold voltage Vth, and the upper arm switch SWH is turned on. On the other hand, when the input switching command is a off command, the upper arm drive unit 71a causes discharge current to flow from the gate of the upper arm switch SWH to the emitter side. As a result, the gate voltage of the upper arm switch SWH falls below the threshold voltage Vth, and the upper arm switch SWH is turned off.

[0043] The lower arm actuator 72 includes a lower arm driving section 72a and a lower arm insulation transmission section 72b. In this embodiment, the structures of each actuator 71 and 72 are basically the same. Therefore, a detailed description of the lower arm actuator 72 will be omitted hereafter.

[0044] The lower arm drive section 72a and the lower arm insulation transmission section 72b in the lower arm driver 72 are configured such that they can operate by supplying the lower arm drive voltage VdL to the insulating power supply 70. The lower arm insulation transmission section 72b in the lower arm driver 72 is configured such that it can operate by supplying the second voltage V2 to the power supply circuit 61.

[0045] When the switching command input via the lower arm insulation transfer unit 72b is an on command, the lower arm drive unit 72a supplies charging current to the gate of the lower arm switch SWL. As a result, the gate voltage of the lower arm switch SWL becomes above the threshold voltage Vth, and the lower arm switch SWL is turned on. On the other hand, when the input switching command is a off command, the lower arm drive unit 72a causes discharge current to flow from the gate of the lower arm switch SWL to the emitter side. As a result, the gate voltage of the lower arm switch SWL falls below the threshold voltage Vth, and the lower arm switch SWL is turned off.

[0046] like Figure 2 and Figure 3 As shown, the control circuit 50 includes a determination signal transmission unit 73 and a determination unit 81. The determination signal transmission unit 73 is provided across the boundary between the low-voltage region and the high-voltage region. While electrically isolating the low-voltage region from the high-voltage region, the determination signal transmission unit 73 transmits the start signal Sg1 and the abnormal signal Sg2 output from the microcomputer 62 to the determination unit 81. In this embodiment, the microcomputer 62 is equivalent to a "start signal output unit". In addition, the determination signal transmission unit 73 is equivalent to a "start signal transmission unit" and an "abnormal signal transmission unit", such as an optocoupler or a magnetic coupler. Furthermore, the determination signal transmission unit 73 can be provided separately to transmit the start signal Sg1 and the abnormal signal Sg2 respectively, or it can be provided as a common transmission unit for both the start signal Sg1 and the abnormal signal Sg2.

[0047] When the user instructs the control system to start by turning on the start switch 33, the microcomputer 62 is then turned on. In this case, in this embodiment, the logic of the start signal Sg1 output from the microcomputer 62 is reversed from L to H. On the other hand, when the user instructs the control system to stop by turning off the start switch 33, the microcomputer 62 is then turned off. In this case, the logic of the start signal Sg1 output from the microcomputer 62 is reversed from H to L.

[0048] The abnormal signal Sg2 indicates whether there is an abnormality in the components of the control system, such as the control circuit 50. If the microcomputer 62 determines that no abnormality has occurred in the control system, it sets the logic of the abnormal signal Sg2 to L. Conversely, if the microcomputer 62 determines that an abnormality has occurred in the control system, it reverses the logic of the abnormal signal Sg2 from L to H.

[0049] Furthermore, malfunctions in the control system include malfunctions such as the inability to supply power from the low-voltage power supply 31 to the control circuit 50, and malfunctions within the control circuit 50 itself. Malfunctions within the control circuit 50 include malfunctions of the microcomputer 62, malfunctions of the power supply circuit 61, malfunctions in the inability to properly transmit switching commands from the microcomputer 62 to the upper and lower arm drivers 71 and 72, and malfunctions in the inability to output voltage from the insulating power supply 70. Malfunctions in the inability to output voltage from the insulating power supply 70 include malfunctions of the insulating power supply 70 itself and malfunctions in the inability to supply power from the low-voltage power supply 31 to the insulating power supply 70. For example, the inability to supply power from the low-voltage power supply 31 to the insulating power supply 70 occurs due to a break in the electrical path from the low-voltage power supply 31 to the insulating power supply 70, such as in the input circuit 60. Additionally, taking the lower arm driver 72 as an example, malfunctions in the inability to properly transmit switching commands include a break in the signal path from the microcomputer 62 to the lower arm insulating transmission section 72b. Furthermore, the aforementioned malfunctions can occur, for example, due to a collision with the vehicle 10.

[0050] The control circuit 50 includes an emergency power supply 80 in its high-voltage region. The emergency power supply 80 generates an emergency drive voltage Veps by supplying the output voltage VH of the smoothing capacitor 24. Various power supplies, such as switching power supplies or series power supplies, are used as the emergency power supply 80. Furthermore, in this embodiment, the emergency power supply 80 is equivalent to a "drive power supply".

[0051] The control circuit 50 includes a normal power supply path 82, a normal diode 83, an emergency power supply path 84, and an emergency switch 85 in its high-voltage region. The normal power supply path 82 connects the output side of the isolated power supply 70 to the lower arm drive unit 72a, supplying the lower arm drive voltage VdL to the lower arm drive unit 72a. The normal diode 83 is positioned in the middle of the normal power supply path 82 with its anode connected to the output side of the isolated power supply 70.

[0052] The portion of the power supply path 82 that is closer to the lower arm drive unit 72a than the usual diode 83 is connected to the emergency power supply 80 via the emergency power supply path 84. An emergency switch 85 is provided in the emergency power supply path 84. The emergency power supply path 84 supplies the emergency drive voltage Veps to the lower arm drive unit 72a.

[0053] The lower arm drive voltage VdL of the insulated power supply 70 is supplied to the determination unit 81 via the normal power path 82. Additionally, the start signal Sg1 and the abnormal signal Sg2 are input to the determination unit 81 via the determination signal transmission unit 73. When the determination unit 81 performs three-phase short-circuit control (hereinafter referred to as ASC control), which opens the upper arm switch SWH (equivalent to three phases) and closes the lower arm switch SWL (equivalent to three phases), it switches the abnormal switch 85 to the on position. Power is then supplied to the lower arm drive unit 72a. Furthermore, the determination unit 81 outputs the ASC execution command SgASC to the lower arm drive unit 72a. The lower arm switch SWL is then closed by the lower arm drive unit 72a.

[0054] use Figure 4 The process for determining whether ASC control can also be performed is explained. This process is repeatedly executed by the determination unit 81, for example, at a predetermined control cycle.

[0055] In step S10, it is determined whether at least one of the following conditions is met: the first condition that the logic of the start signal Sg1 is H and the second condition that the lower arm drive voltage VdL is above the determination voltage Vs. Here, the determination voltage Vs only needs to be set to a value greater than 0.

[0056] If it is determined in step S10 that neither the first condition nor the second condition is met, proceed to step S11 and determine that the system is in a prohibited state under ASC control.

[0057] If, in step S10, it is determined that at least one of the first and second conditions is met, proceed to step S12 and determine that the system is in an ASC-controlled permitted state.

[0058] use Figure 5 The process for determining whether to perform ASC control is explained. This process is repeatedly executed by the determination unit 81, for example, at a predetermined control cycle.

[0059] In step S20, it is determined whether the system is in an ASC control permitted state. If a negative determination is made in step S20, the system is determined to be in an ASC control prohibited state, and the process proceeds to step S21. In step S21, ASC control is not executed.

[0060] On the other hand, if a positive determination is made in step S20, the process proceeds to step S22, where it is determined whether at least one of the following conditions is met: the third condition that the logic of the abnormal signal Sg2 is H, and the fourth condition that the lower arm drive voltage VdL is lower than the specified voltage Vp. Here, the specified voltage Vp is set to a value that can be determined to be a value that indicates a sufficient period has elapsed until the upper arm switch SWH is turned off; for example, it can be set to a value that is the same as or less than the threshold voltage Vth.

[0061] If, in step S22, it is determined that neither the third nor the fourth condition is met, the process proceeds to step S21. Conversely, if, in step S20, it is determined that at least one of the third and fourth conditions is met, the process proceeds to step S23, and ASC control is executed. Specifically, the fault switch 85 is switched to ON, and the ASC execution command SgASC is output to the lower arm drive unit 72a. Furthermore, during the processing of step S23, the switching command output from the microcomputer 62 to the upper arm driver 71 (equivalent to a three-phase drive) can also be set as a disconnect command.

[0062] Furthermore, in this embodiment, the determination unit 81 is equivalent to the "short circuit control unit", "start-up determination unit" and "abnormality determination unit".

[0063] use Figure 6 The control method of this embodiment will be explained. Figure 6 (a) indicates the operating state of the starter switch 33. Figure 6 (b) represents the operating state of the microcomputer 62. Figure 6 (c) represents the shift in the upper arm drive voltage VdH. Figure 6 (d) represents the shift in the lower arm drive voltage VdL. Figure 6 (e) indicates the shift of the abnormal driving voltage Veps. Figure 6 (f) represents the shift of the start signal Sg1. Figure 6 (g) indicates the permitted / prohibited status controlled by ASCII. Figure 6 (h) represents the shift of the abnormal signal Sg2. Figure 6 (i) represents the driving state of the lower arm switch SWL.

[0064] Before time t1, the start switch 33 is open, and the vehicle 10 stops. At time t1, with the start switch 33 open, traction of the vehicle 10 begins. Traction by the vehicle 10 causes the rotor 12 of the rotary motor 11 to rotate, generating a back electromotive force in the winding 13. If the first cut-off switch 23a and the second cut-off switch 23b are open with the start switch 33 open, the smoothing capacitor 24 is charged by the back electromotive force. Because the output voltage VH of the smoothing capacitor 24 is supplied to the emergency power supply 80, the emergency drive voltage Veps rises.

[0065] When towing vehicle 10, since the start switch 33 is off, the lower arm drive voltage VdL is 0V, which is lower than the determination voltage Vs. Furthermore, the logic of the start signal Sg1 input to the determination unit 81 is L. Therefore, ASC control is disabled, and ASC control is not executed when vehicle 10 is towing.

[0066] At time t2, traction of vehicle 10 ends, and vehicle 10 comes to a stop. At time t3, the start switch 33 is turned on. Power is then supplied from the low-voltage power supply 31 to the power circuit 61, and from the power circuit 61 to the microcomputer 62. At time t4, the microcomputer 62 is turned on. Power is also supplied from the low-voltage power supply 31 to the insulating power supply 70, and the upper arm drive voltage VdH and lower arm drive voltage VdL begin to rise. Then, at time t5, the lower arm drive voltage VdL reaches the determination voltage Vs. When the determination voltage Vs is set to a value greater than, for example, the threshold voltage Vth, during ASC control, the lower arm drive unit 72a can use the lower arm drive voltage VdL to turn on the lower arm switch SWL. Since at least one of the first and second conditions is met at time t5, the determination unit 81 determines that the control system is started, switching from the ASC control prohibited state to the permitted state. Furthermore, in Figure 6 In the example shown, the logic of the start signal Sg1 becomes the same as the first timing of H and the second timing of the lower arm drive voltage VdL reaching the determination voltage Vs, but it is not limited to this.

[0067] At time t6, if an anomaly occurs preventing power supply from the low-voltage power supply 31 to the control circuit 50, the isolation power supply 70 stops, and the upper arm drive voltage VdH and lower arm drive voltage VdL begin to decrease. Subsequently, at time t7, the lower arm drive voltage VdL falls below the specified voltage Vp. Furthermore, at... Figure 6 In the example shown, at time t7, the abnormal signal Sg2 output from the determination signal transmission unit 73 is logically inverted to H.

[0068] After the detection unit 81 detects that the lower arm drive voltage VdL begins to decrease, it waits until the upper arm drive voltage VdH falls below the aforementioned threshold voltage Vth, and then determines that an abnormality has occurred in the control system. Consequently, the determination unit 81 switches the abnormality switch 85 to the ON position and outputs the ASC execution command SgASC to the lower arm drive unit 72a. As a result, ASC control is executed by activating the lower arm switch SWL. Furthermore, in this embodiment, the lower arm switch SWL is equivalent to an "ON-side switch".

[0069] When the lower arm drive voltage VdL is lower than the specified voltage Vp, the upper arm switch SWH, which is equivalent to a three-phase switch, cannot be turned on through the upper arm drive unit 71a, and the upper arm switch SWH, which is equivalent to a three-phase switch, is turned off. Therefore, it is possible to prevent short circuits between the upper and lower arms. Furthermore, in this embodiment, the upper arm switch SWH is equivalent to a "disconnect side switch".

[0070] Furthermore, when the start switch 33 is off, it also becomes the disabled state for ASC control. Figure 7 (a) indicates the operating state of the starter switch 33.Figure 7 (b) represents the operating state of the microcomputer 62. Figure 7 (c) represents the shift in the upper arm drive voltage VdH and the lower arm drive voltage VdL. Figure 7 (d) indicates the permitted / prohibited status controlled by the ASCII control.

[0071] At time t1, when the start switch 33 is open, the system switches from the permitted state to the prohibited state of ASC control. Then, at time t2, the microcomputer 62 is deactivated, and the upper arm drive voltage VdH and lower arm drive voltage VdL begin to decrease. Furthermore, at time t3, both the upper arm drive voltage VdH and lower arm drive voltage VdL become 0V. With the start switch 33 open, the logic of the start signal Sg1 is L, thus becoming the prohibited state of ASC control. Therefore, it is possible to prevent ASC control from being executed when towing vehicle 10.

[0072] use Figure 8 Further Figure 4 and Figure 5 The processing method will be explained. Figure 8 (a)~(i) and the previous Figure 6 The (a) to (i) correspond. Additionally, Figure 8 The times t1, t2, ..., t7 and Figure 6 The times t1, t2, ..., t7 correspond to each other. For example... Figure 8 As shown in time t1 to t2 of (g), when towing vehicle 10, due to some reason, the control circuit 50 malfunctions, sometimes switching to the permitted state even when it is actually in the prohibited state of ASC control. Even in this case, the determination unit 81 performs a predetermined control cycle. Figure 4 The process shown can also switch the erroneously configured ASC control from the permitted state to the prohibited state.

[0073] like Figure 8 As shown in times t5 to t6 (g), during normal driving of vehicle 10, due to some reason, the control circuit 50 malfunctions, sometimes switching to the prohibited state even when it is actually in the permitted state of ASC control. Even in this case, the determination unit 81 performs a predetermined control cycle... Figure 4 The process shown can also switch the erroneously configured ASC control from a disabled state to a enabled state.

[0074] Based on the implementation method described above, the following effects can be obtained.

[0075] The determination unit 81 determines that the control system has started and switches from the ASC control prohibited state to the permitted state. Then, while in the permitted state, the determination unit 81 executes ASC control if it determines that an abnormality has occurred in the control system. Towing of vehicle 10 usually occurs before the control system starts. Before the control system starts, the start switch 33 is open, and the lower arm drive voltage VdL is lower than the determination voltage Vs. Therefore, before the control system starts, it is in the ASC control prohibited state. This prevents ASC control from being executed when towing vehicle 10. As a result, it prevents the inverter 20 from overheating when towing vehicle 10.

[0076] If the lower arm switch SWL is turned on via ASC control after the insulating power supply 70 is stopped, and the voltage supplied from the insulating power supply 70 to the upper arm switch SWH is not sufficiently reduced, a short circuit between the upper and lower arms may occur.

[0077] To address this, in this embodiment, the determination unit 81 determines that an abnormality has occurred when the lower arm drive voltage VdL is lower than a predetermined voltage Vp. Therefore, ASC control is performed when the gate voltage of the upper arm switch SWH is sufficiently reduced. As a result, when the upper arm switch SWH is turned on, the lower arm switch SWL will not be turned on. Consequently, short circuits between the upper and lower arms can be prevented during the execution of ASC control.

[0078] The determination unit 81 periodically performs a determination of whether the system is in either a permitted or prohibited state under ASC control. Therefore, even if the system is actually in a prohibited state but becomes permitted for some reason before the control system starts, it can be determined to be in a prohibited state in the next determination. Conversely, even if the system is actually in a permitted state but becomes prohibited for some reason after the control system starts, it can be determined to be in a permitted state in the next determination. As a result, it is possible to prevent erroneous ASC control operations performed before the control system starts, or to prevent inaction by failing to perform ASC control operations even if an anomaly occurs after the control system starts.

[0079] <Modifications of the First Embodiment>

[0080] · You can also Figure 4 Step S10 involves determining whether the following conditions are met: a first condition that the start signal Sg1 is logically H, and a second condition that the lower arm drive voltage VdL is above the determination voltage Vs. This improves the accuracy of the control system's start-up determination.

[0081] ·exist Figure 4In step S10, either the start signal Sg1 or the lower arm drive voltage VdL can be used. For example, when using the lower arm drive voltage VdL, step S10 becomes a process of determining whether the second condition is met. In this case, the control circuit 50 may not include the determination signal transmission unit 73 for transmitting the start signal Sg1.

[0082] · You can also Figure 5 Step S22 is set to determine whether the third condition of the abnormal signal Sg2 being H and the fourth condition of the lower arm drive voltage VdL being lower than the specified voltage Vp are true.

[0083] ·exist Figure 5 In step S22, either the abnormal signal Sg2 or the lower arm drive voltage VdL can be used. For example, when using the lower arm drive voltage VdL, the processing in step S22 becomes a process of determining whether the aforementioned fourth condition is met. In this case, the control circuit 50 may not include the determination signal transmission unit 73 for transmitting the abnormal signal Sg2.

[0084] • As an ASC control, it can also perform control to turn on the upper arm switch SWH (equivalent to a three-phase switch) and turn off the lower arm switch SWL (equivalent to a three-phase switch). In this case, the emergency power supply 80 only needs to be set separately for each of the upper arm drive units 71a (equivalent to a three-phase switch).

[0085] The determination unit 81 can also determine the abnormality of the control system based on the upper arm drive voltage VdH, instead of based on the lower arm drive voltage VdL. In this case, the determination unit 81 can obtain the information of the upper arm drive voltage VdH via the insulation transmission unit.

[0086] • The specified voltage Vp can also be set to a value that is greater than the threshold voltage Vth but less than the first voltage V1.

[0087] <Second Implementation>

[0088] Hereinafter, the second embodiment will be described focusing on its differences from the first embodiment. In this embodiment, as... Figure 9 As shown, in order to directly supply voltage to the gate of the lower arm switch SWL, the structure of the high-voltage region of the control circuit 50 is partially modified. Additionally, in Figure 9 For convenience, the previous... Figure 3 The structures shown are labeled with the same symbols.

[0089] In the high-voltage region of the control circuit 50, a first limiting diode 92 is provided in the gate charging path that connects the lower arm drive unit 72a to the gate of the lower arm switch SWL. The first limiting diode 92 is provided with its anode connected to the lower arm drive unit 72a side. Furthermore, in Figure 9 The diagram of the gate discharge path of the lower arm switch SWL is omitted in the image.

[0090] The control circuit 50 includes an emergency charging switch 93, an emergency charging path 94, and a second limiting diode 95. The emergency charging switch 93 connects the emergency power supply 80 to the emergency charging path 94. The gate of the lower arm switch SWL is connected in the emergency charging path 94. The second limiting diode 95 is configured in the emergency charging path 94 with its anode connected to the side of the emergency charging switch 93.

[0091] If at least one of the following conditions is met—a third condition that determines the abnormal signal Sg2 as having logic H and a fourth condition that the lower arm drive voltage VdL is lower than the specified voltage Vp—the determination unit 81 switches the abnormal charging switch 93 to the on. This initiates the direct supply of the abnormal drive voltage Veps from the abnormal power supply 80 to the gate of each lower arm switch SWL. As a result, ASC control is executed.

[0092] According to the above-described embodiment, the same effects as the first embodiment can be obtained.

[0093] <Third Implementation Method>

[0094] The third embodiment will be described below, focusing on its differences from the first embodiment. In this embodiment, a structure for controlling the start-up of the power supply 80 for abnormal situations is added, such as... Figure 10 As shown, the structure of the high-voltage region of the control circuit 50 has been partially modified. Additionally, in Figure 10 For convenience, the previous... Figure 3 The structures shown are labeled with the same symbols.

[0095] The emergency power supply 80 includes a control unit 80a. An emergency power supply path 84 is connected to the output side of the emergency power supply 80. The control unit 80a controls the emergency drive voltage Veps output from the emergency power supply 80 to a target voltage. In this embodiment, the control unit 80a is equivalent to a "power supply control unit".

[0096] The start signal Sg1 output from the microcomputer 62 is input to the control unit 80a via the determination signal transmission unit 73.

[0097] The control circuit 50 includes a start-up determination path 86. A portion of the power supply path 82 that is closer to the isolated power supply 70 than the normally used diode 83 is connected to the control unit 80a via the start-up determination path 86. The lower arm drive voltage VdL of the isolated power supply 70 is input to the control unit 80a via the start-up determination path 86.

[0098] Control unit 80a via previous Figure 4 The same process is used to determine whether the control system has started. If the control system is determined to be started, the abnormal power supply 80 is activated. Specifically, the control unit 80a determines whether at least one of the following conditions is met: a first condition where the logic of the input start signal Sg1 is H and a second condition where the input lower arm drive voltage VdL is above the determination voltage Vs. If the control unit 80a determines that neither the first nor the second condition is met, it determines that the control system has not started and is in an ASC control disabled state. On the other hand, if the control unit 80a determines that at least one of the first and second conditions is met, it determines that the control system has started and is in an ASC control enabled state.

[0099] use Figure 11 The control method of this embodiment will be explained. Figure 11 (a) indicates the operating state of the starter switch 33. Figure 11 (b) represents the shift in the lower arm drive voltage VdL. Figure 11 (c) indicates the shift of the start signal Sg1. Figure 11 (d) indicates the shift of the abnormal driving voltage Veps. Figure 11 (e) indicates the permitted / prohibited status controlled by the ASCII control.

[0100] At time t1 when the vehicle is stopped, the start switch 33 is turned on. Before time t2, the control unit 80a determines that neither the first nor the second condition is met. Therefore, the emergency power supply 80 does not operate. In this state, even if the output voltage VH of the smoothing capacitor 24 is supplied to the emergency power supply 80 through the traction of the vehicle 10, the emergency drive voltage Veps will not rise. Therefore, power cannot be supplied to the lower arm drive unit 72a, and the execution of ASC control can be reliably prevented.

[0101] Furthermore, at time t2 during normal driving, the lower arm drive voltage VdL reaches the determination voltage Vs, and the logic of the start signal Sg1 is H. The control unit 80a determines that the control system is started if at least one of the first and second conditions is met. Therefore, the control unit 80a switches from the ASC-controlled prohibited state to the permitted state and starts the abnormal power supply 80.

[0102] In the embodiment described above, the control unit 80a starts the emergency power supply 80 on the condition that the control system is started. Therefore, the emergency power supply 80 does not operate before the control system is started. In this case, since the power used for ASC control is not supplied to the gate of the lower arm switch SWL, ASC control is not performed. As a result, it is possible to reliably prevent the execution of ASC control when traction vehicle 10 is in operation, and further, it is possible to reliably prevent the inverter 20 from overheating when traction vehicle 10 is in operation.

[0103] <Modifications of the Third Embodiment>

[0104] Alternatively, the control unit 80a in the control unit 80a and the determination unit 81 can be configured to determine the permission / prohibition status of ASC control, instead of the structure where both the control unit 80a and the determination unit 81 determine the permission / prohibition status of ASC control. In this case, the control unit 80a is equivalent to a "start determination unit".

[0105] The control unit 80a can also determine the start of the control system using either the start signal Sg1 or the lower arm drive voltage VdL. For example, the control unit 80a can determine that the control system is started when it determines that the lower arm drive voltage VdL has reached the determination voltage Vs. According to this structure, unlike the isolated power supply 70, there is no need to add a structure to transmit the start-up status of the control system to the control unit 80a. As a result, the number of components in the control circuit 50 can be reduced.

[0106] <Fourth Implementation>

[0107] The fourth embodiment will be described below, focusing on the differences from the third embodiment.

[0108] like Figure 12 As shown, the abnormal signal Sg2 output from the determination signal transmission unit 73 can also be configured to be input to the control unit 80a. The control unit 80a, through the previous... Figure 5 The same processing is used to determine whether an anomaly has occurred in the control system. Specifically, the control unit 80a determines whether at least one of the following conditions is met: a third condition where the logic of the input anomaly signal Sg2 is H, and a fourth condition where the input lower arm drive voltage VdL is lower than a specified voltage Vp. If the control unit 80a determines that neither the third nor the fourth condition is met, it determines that no anomaly has occurred in the control system and outputs a disconnect command for the anomaly switch 85. On the other hand, if the control unit 80a determines that at least one of the third or fourth conditions is met, it outputs a turn-on command for the anomaly switch 85 and outputs an ASC execution command SgASC to the lower arm drive unit 72a.

[0109] The determination unit 81 determines whether at least one of the following conditions is met: a third condition where the logic of the input abnormal signal Sg2 is H, and a fourth condition where the input lower arm drive voltage VdL is lower than a specified voltage Vp. If the determination unit 81 determines that neither the third nor the fourth condition is met, it determines that no abnormality has occurred in the control system and outputs a disconnect command for the abnormality switch 85. On the other hand, if the determination unit 81 determines that at least one of the third and fourth conditions is met, it outputs a turn-on command for the abnormality switch 85 and outputs an ASC execution command SgASC to the lower arm drive unit 72a.

[0110] In this embodiment, the fault switch 85 is switched to ON by outputting an ON command to the fault switch 85 from both the control unit 80a and the determination unit 81. Additionally, by outputting an ASC execution command SgASC to the lower arm drive unit 72a from both the control unit 80a and the determination unit 81, the three-phase lower arm switch SWL is effectively ON.

[0111] According to this embodiment, the determination results of the control unit 80a and the determination unit 81 are used in determining whether to perform ASC control. Therefore, the accuracy of determining whether an anomaly has occurred in the control system can be improved.

[0112] <Modifications of the Fourth Embodiment>

[0113] Alternatively, the control unit 80a in the control unit 80a and the determination unit 81 can be configured to determine whether to perform ASC control, instead of the structure where both the control unit 80a and the determination unit 81 determine whether to perform ASC control. In this case, the control unit 80a is equivalent to an "abnormality determination unit" and a "short circuit control unit".

[0114] The control unit 80a can also determine the start of the control system using either the start signal Sg1 or the lower arm drive voltage VdL. For example, the control unit 80a can also determine that an abnormality has occurred in the control system if it determines that the lower arm drive voltage VdL is lower than the specified voltage Vp. According to this structure, unlike the isolated power supply 70, there is no need to add a structure to transmit the abnormality in the control system to the control unit 80a. As a result, the number of components in the control circuit 50 can be reduced.

[0115] • Control unit 80a can also be used with the previously Figure 8 Similarly, the structure described herein determines whether ASC control can be performed within a specified control cycle.

[0116] <Other Implementation Methods>

[0117] · It is also possible to omit the cooling device 40 from the control system.

[0118] • The switch constituting the inverter 20 is not limited to IGBT; for example, it can also be an N-channel MOSFET with a built-in body diode.

[0119] • The control quantity of the rotary motor 11 is not limited to torque; for example, it can also be the rotational speed of the rotor 12 of the rotary motor 11.

[0120] The control unit and methods described in this disclosure can also be implemented using a dedicated computer, which is provided by comprising a processor and memory, the processor being programmed to perform one or more functions embodied in the computer program. Alternatively, the control unit and methods described in this disclosure can be implemented using a dedicated computer, which is provided by comprising a processor composed of one or more dedicated hardware logic circuits. Alternatively, the control unit and methods described in this disclosure can be implemented using one or more dedicated computers, which are constituted by a combination of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. Furthermore, the computer program can also be stored on a computer-readable non-transitory tangible storage medium as instructions executable by a computer.

[0121] While this disclosure has been described based on embodiments, it should be understood that this disclosure is not limited to the above embodiments and structures. This disclosure also includes various modifications and equivalent variations. Furthermore, various combinations and arrangements, and consequently, combinations and arrangements containing only one element, or more than or less thereof, also fall within the scope and spirit of this disclosure.

Claims

1. A control circuit for a power converter, the control circuit of the power converter constituting a system installed in a vehicle, the system comprising: A multiphase rotating electric motor having a rotor capable of transmitting power to a drive wheel; as well as A power converter having upper and lower arm switches electrically connected to each phase winding of the rotating motor, wherein the control circuit of the power converter includes: An anomaly determination unit determines whether an anomaly has occurred in the system. Startup determination unit, which determines whether the system has started; and The short-circuit control unit, upon determining that the system has started and that the abnormality has occurred, executes short-circuit control to turn on the on-side switch of one of the upper and lower arms and turn off the off-side switch of the other arm. The short-circuit control unit and the start-up determination unit are located in the high-voltage area. The system includes: A start switch, which is operated by a user of the vehicle, indicating the start of the system by turning it on and indicating the stop of the system by turning it off; and A low-voltage power supply located in a low-voltage region that is electrically insulated from the high-voltage region. The control circuit of the power converter includes an isolated power supply that spans the boundary between the low-voltage region and the high-voltage region. The isolated power supply is located in both the low-voltage and high-voltage regions. When the start switch is turned on, power is supplied from the low-voltage power supply to generate power for the gates of the on-side switch and the off-side switch. The start-up determination unit determines that the system is started if the output voltage of the insulating power supply is determined to be above a predetermined voltage.

2. A control circuit for a power converter, the control circuit of the power converter constituting a system installed in a vehicle, the system comprising: A multiphase rotating electric motor having a rotor capable of transmitting power to a drive wheel; as well as A power converter having upper and lower arm switches electrically connected to each phase winding of the rotating motor, wherein the control circuit of the power converter includes: An anomaly determination unit determines whether an anomaly has occurred in the system. Startup determination unit, which determines whether the system has started; and The short-circuit control unit, upon determining that the system has started and that the abnormality has occurred, executes short-circuit control to turn on the on-side switch of one of the upper and lower arms and turn off the off-side switch of the other arm. The system includes a start switch, which is operated by the user of the vehicle to indicate the start of the system by turning it on and to indicate the stop of the system by turning it off. The short-circuit control unit and the start-up determination unit are located in the high-voltage area. The control circuit of the power converter includes: A start signal output unit is provided in a low-voltage area that is electrically insulated from the high-voltage area, and outputs a start signal by turning on the start switch; A start signal transmission unit is provided in both the high-voltage and low-voltage regions, spanning the boundary between them. This unit electrically insulates the high-voltage and low-voltage regions while transmitting the start signal output from the start signal output unit to the high-voltage region. The start determination unit determines that the system is started if it determines that the start signal has been input via the start signal transmission unit.

3. A control circuit for a power converter, the control circuit of the power converter constituting a system installed in a vehicle, the system comprising: A multiphase rotating electric motor having a rotor capable of transmitting power to a drive wheel; as well as A power converter having upper and lower arm switches electrically connected to each phase winding of the rotating motor, wherein the control circuit of the power converter includes: An anomaly determination unit determines whether an anomaly has occurred in the system. Startup determination unit, which determines whether the system has started; and The short-circuit control unit, upon determining that the system has started and that the abnormality has occurred, executes short-circuit control to turn on the on-side switch of one of the upper and lower arms and turn off the off-side switch of the other arm. The short-circuit control unit and the start-up determination unit are located in the high-voltage area. The system includes: A start switch, which is operated by a user of the vehicle, indicating the start of the system by turning it on and indicating the stop of the system by turning it off; and A low-voltage power supply located in a low-voltage region that is electrically insulated from the high-voltage region. The control circuit of the power converter includes: An insulated power source is provided in the low-voltage region and the high-voltage region, spanning the boundary between the low-voltage region and the high-voltage region, and supplies power from the low-voltage power source to generate power to the respective gates of the on-side switch and the off-side switch when the start switch is turned on. A start signal output unit, wherein the start signal output unit is disposed in the low-voltage region, and outputs a start signal by turning on the start switch; and A start signal transmission unit is provided in both the high-voltage and low-voltage regions, spanning the boundary between them. This unit electrically insulates the high-voltage and low-voltage regions while transmitting the start signal output from the start signal output unit to the high-voltage region. The start-up determination unit determines that the system is started if it determines that the output voltage of the insulating power supply is above a predetermined voltage and that the start-up signal has been input via the start-up signal transmission unit.

4. The control circuit of the power converter as described in claim 1 or 3, characterized in that, The anomaly determination unit is located in the high-voltage area and determines whether the anomaly has occurred based on the output voltage of the insulating power supply.

5. The control circuit of the power converter as described in claim 4, characterized in that, If the voltage supplied from the insulating power source to the gate of the on-side switch is lower than a specified voltage, the abnormality determination unit determines that the abnormality has occurred.

6. The control circuit of the power converter as described in any one of claims 1 to 5, characterized in that, The startup determination unit periodically performs the following process: if the system is determined to be starting, it determines that the system is in a permitted state for short-circuit control; if the system is not determined to be starting, it determines that the system is in a prohibited state for short-circuit control. The short-circuit control unit executes the short-circuit control condition based on the condition that it is in the permitted state and that the abnormality has occurred.

7. The control circuit of the power converter as described in any one of claims 1 to 6, characterized in that, The control circuit of the power converter includes a drive power supply disposed in the high-voltage region and supplying power to the gate of the on-side switch. The short-circuit control unit uses power generated by the drive power supply to perform the short-circuit control. The drive power supply includes a power control unit that starts the drive power supply when the system is determined to be started.

8. The control circuit of the power converter as described in any one of claims 1, 3 to 5, characterized in that, The control circuit of the power converter includes a drive power supply disposed in the high-voltage region and supplying power to the gate of the on-side switch. The short-circuit control unit uses power generated by the drive power supply to perform the short-circuit control. The drive power supply includes a power control unit that starts the drive power supply when the system is determined to be started. The power control unit The system is deemed to be started if the output voltage of the insulated power supply is determined to be above a specified voltage. If the system is determined to be started, the drive power supply is started.

9. The control circuit of the power converter as described in claim 8, characterized in that, The power control unit determines whether the abnormality has occurred based on the output voltage of the insulated power supply. The short-circuit control unit executes the short-circuit control condition when the abnormality determination unit and the power control unit determine that the abnormality has occurred and that the system has started.

10. The control circuit of the power converter as described in claim 9, characterized in that, If the voltage supplied from the insulated power source to the gate of the on-side switch is lower than a specified voltage, the power control unit determines that the abnormality has occurred.

11. The control circuit of the power converter as described in any one of claims 7 to 10, characterized in that, The power control unit periodically performs the following process: if it determines that the system has started, it determines that the system is in a permitted state for short-circuit control; if it does not determine that the system has started, it determines that the system is in a prohibited state for short-circuit control. The short-circuit control unit executes the short-circuit control condition when the start-up determination unit and the power control unit determine that the system is in the permitted state and that the abnormality has occurred.

12. The control circuit of the power converter as described in any one of claims 1 to 11, characterized in that, The short-circuit control unit prohibits the execution of short-circuit control when instructing the system to stop.

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