Vehicle control device

Abstract

To suppress starting of a system from being restricted due to temporal defect.SOLUTION: A vehicle control device according to the present invention, which controls a vehicle using electric power as at least a portion of a drive source, comprises a discharging control part that makes a driving circuit having a motor and a capacitor perform active discharge in which currents are carried to a d-axis of the motor to discharge the capacitor when a system is terminated, and a determining part that determines whether the system should be permitted to start up or not, at the time of starting-up the system subsequently. When detecting abnormal discharge in the active discharge, the discharging control part makes a memorizing part memorize the abnormal discharge. When a voltage of the capacitor is below a threshold, the determining part permits the system to start-up even when the abnormal discharge is recorded.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a vehicle control device. [Background technology]

[0002] 2. Description of the Related Art In electrically powered vehicles such as hybrid vehicles, when the system is shut down, for example by shutting down the ignition power, active discharging is performed in which a current is passed through a motor in a drive circuit to discharge a capacitor in the circuit.

[0003] In this case, if some kind of fault occurs and active discharge fails, a power conversion device capable of identifying the faulty part of the drive circuit has been disclosed (see, for example, Patent Document 1).In addition, a power conversion device has been disclosed that notifies the state of a switching mechanism that electrically connects or disconnects a capacitor and the capacitor's discharge circuit, and the discharge status of the charge accumulated in the capacitor (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 039277 [Patent Document 2] International Publication No. 2011 / 111208 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, even if a discharge abnormality occurs in the capacitor and active discharge fails, there are cases where no failure is found in the drive circuit. In such cases, it is presumed that active discharge failed due to a temporary cause such as poor contact in the connector. However, since the discharge abnormality determination result is recorded, the system will not be allowed to start again until this record is erased, and in the worst case scenario, it may lead to a breakdown on the road.

[0006] An object of the present disclosure is to provide a vehicle control device that can suppress restrictions on system startup caused by a temporary malfunction. [Means for solving the problem]

[0007] A vehicle control device according to the present disclosure is a vehicle control device that controls a vehicle that uses electric power at least as part of a drive source, and includes a discharge control unit that, in a drive circuit having a motor and a capacitor, performs active discharge by flowing a current through a d-axis of the motor to discharge the capacitor when the system is shut down, and a determination unit that determines whether or not to permit the system to be started at the next system startup. a discharge circuit that performs passive discharge by discharging the capacitor by power consumption in an internal circuit that is composed of the capacitor and a discharge resistor; When the discharge control unit detects a discharge abnormality in the active discharge, the discharge control unit stores a record of the discharge abnormality in a storage unit, and the determination unit determines whether the discharge abnormality is detected at the next system startup. To, The discharge abnormality record is stored. There was none case for Allow system to start When the discharge abnormality is recorded, the next time the system is started, it is determined whether the voltage of the capacitor is equal to or lower than a threshold value. If the result of the determination is that the voltage of the capacitor is equal to or lower than the threshold value, the system is permitted to start up, and if the result of the determination is that the voltage of the capacitor exceeds the threshold value, the system is not permitted to start up. . Effect of the Invention

[0008] According to the vehicle control device of the present disclosure, it is possible to prevent restrictions on system startup caused by a temporary malfunction. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a drive system according to an embodiment. [Diagram 2] FIG. 2 is a block diagram illustrating an example of a hardware configuration of the hybrid control ECU together with a peripheral configuration according to the embodiment. [Figure 3A] FIG. 3A is a diagram illustrating an example of an operation performed by the hybrid control ECU according to the embodiment when active discharging is normally performed. [Figure 3B]FIG. 3B is a diagram illustrating an example of an operation performed by the hybrid control ECU according to the embodiment when a discharge abnormality occurs during active discharge. [Figure 3C] FIG. 3C is a diagram illustrating another example of the operation performed by the hybrid control ECU according to the embodiment when a discharge abnormality occurs during active discharge. [Figure 4] FIG. 4 is a flowchart illustrating an example of a procedure of a process performed by the hybrid control ECU according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a vehicle control device according to the present disclosure will be described with reference to the drawings.

[0011] (Example of drive system configuration) 1 is a diagram showing an example of the configuration of a drive system 1 according to an embodiment. The drive system 1 according to the embodiment is mounted on a vehicle such as a hybrid electric vehicle (HEV) that uses electric power from a battery and power from an internal combustion engine as drive sources, and supplies power to the vehicle.

[0012] As shown in FIG. 1, the drive system 1 includes a generator 11, a motor 12, a power control device 20, a battery 30, a DC / AC converter 40, and a hybrid control ECU (Electronic Control Unit) 50.

[0013] Both the generator 11 and the motor 12 are three-phase AC motors that supply three-phase AC driving currents, namely, U-phase, V-phase, and W-phase.

[0014] The generator 11 is connected to an internal combustion engine, such as an engine (not shown), of the vehicle, and is configured as a motor generator that mainly operates as a generator. The generator 11 converts at least a part of the driving force generated by the internal combustion engine into electric power. The electric power converted by the generator 11 is used to charge the battery 30 or drive the motor 12.

[0015] The motor 12 is driven by electric power from a generator 11 that generates power using power from the internal combustion engine, and is configured as a motor generator that mainly outputs power for driving and regenerative braking force. In other words, the vehicle runs solely on the power from the motor 12. It is also possible to charge the battery 30 by the regenerative braking force output from the motor 12.

[0016] The power control device 20 is interposed between the generator 11 and the motor 12, and the battery 30, and is configured as a PCU (Power Control Unit) or the like that controls the power from the drive source.

[0017] The power control device 20 includes an inverter 21, a step-up converter 22, a step-down converter 23, a DC / DC converter 24, a motor generator (MG) ECU 25, a discharge resistor 261, a smoothing capacitor 262, a filter capacitor 263, current sensors 211 and 212, and voltage sensors 265a to 265c.

[0018] The inverter 21 includes a plurality of switching elements 213a-213f that drive the generator 11, and a plurality of switching elements 214a-214f that drive the motor 12. Each of the switching elements 213a-213f, 214a-214f includes a transistor such as an insulated gate bipolar transistor (IGBT), and a diode connected in parallel in the reverse direction to the transistor.

[0019] The individual transistors are paired in pairs, one on the source side and the other on the sink side with respect to the high voltage power line and the negative power line, and the connection points between the two transistors in a pair are electrically connected to the generator 11 or the three-phase coils of the motor 12, namely, the U-phase, V-phase, and W-phase.

[0020] The boost converter 22 includes a plurality of switching elements 221a, 221b, and boosts the power from the battery 30. The switching elements 221a, 221b of the boost converter 22 also each include a transistor such as an IGBT, and a diode connected in parallel to the transistor in the reverse direction.

[0021] The step-down converter 23 is, for example, a reactor, and steps down the power from the motor 12 and the like.

[0022] One end of the reactor of the step-down converter 23 is electrically connected to the positive power line. The other end of the reactor is electrically connected to the emitter of one of the transistors of the switching elements 221a, 221b and the collector of the other transistor. The collector of the one of the transistors is electrically connected to the high-voltage power line. The emitter of the other transistor is electrically connected to the negative power line.

[0023] A smoothing capacitor 262 is interposed on the inverter 21 side of the boost converter 22. The positive terminal of the smoothing capacitor 262 is electrically connected to the collector of one of the transistors of the boost converter 22 via a high-voltage power line. The negative terminal of the smoothing capacitor 262 is electrically connected to the emitter of the other transistor of the boost converter 22 via a negative power line.

[0024] As a result, the voltage boosted by the step-down converter 23 is smoothed by the smoothing capacitor 262 .

[0025] Discharge resistor 261 is provided in association with smoothing capacitor 262, and consumes internal power to discharge the charge stored in smoothing capacitor 262, for example, after the ignition power of the vehicle is turned off.

[0026] The configuration including the smoothing capacitor 262 and the discharge resistor 261 may be referred to as a discharge circuit 2.

[0027] A filter capacitor 263 is provided on the battery 30 side of the boost converter 22 and the step-down converter 23. A positive terminal of the filter capacitor 263 is electrically connected to one end of the reactor of the step-down converter 23 via a positive power line. A negative terminal of the filter capacitor 263 is electrically connected to the negative power line.

[0028] As a result, the voltage on the battery 30 side of boost converter 22, that is, the voltage applied to boost converter 22, is smoothed by filter capacitor 263.

[0029] The configuration including generator 11, motor 12, inverter 21, step-up converter 22, step-down converter 23, discharge resistor 261, smoothing capacitor 262, and filter capacitor 263 may be referred to as drive circuit 3. Drive circuit 3 may include current sensors 211, 212, and voltage sensors 265a to 265c.

[0030] The battery 30 is, for example, a lithium ion secondary battery or a nickel-hydrogen secondary battery, and is capable of receiving power from the generator 11 and the motor 12, storing the power, and also capable of supplying power to the generator 11 and the motor 12.

[0031] Current sensors 211, 212 are provided between the generator 11 and the inverter 21, and between the motor 12 and the inverter 21. The current sensors 211, 212 detect the currents flowing through the generator 11 and the motor 12, respectively.

[0032] A voltage sensor 265a is provided between the terminals of the smoothing capacitor 262. The voltage sensor 265a detects a terminal voltage VH of the smoothing capacitor 262. The terminal voltage VH of the smoothing capacitor 262 corresponds to a voltage boosted by the boost converter 22.

[0033] A voltage sensor 265b is provided between the terminals of the filter capacitor 263. The voltage sensor 265b detects a voltage VL between the terminals of the filter capacitor 263. The voltage VL between the terminals of the filter capacitor 263 corresponds to a voltage before being boosted by the boost converter 22.

[0034] A voltage sensor 265c is provided between the terminals of the battery 30. The voltage sensor 265c detects the voltage between the terminals of the battery 30, that is, the battery voltage VB applied from the battery 30 to the boost converter 22.

[0035] The DC / DC converter 24 is connected to the output side of the battery 30, and converts a direct current (DC) voltage from the battery 30 into an operating voltage for various devices of a low voltage system such as an auxiliary battery. In other words, the DC / DC converter 24 steps down the high voltage from the battery 30 and supplies it to various devices of a low voltage system such as an auxiliary battery.

[0036] The MG-ECU 25 is configured as a computer equipped with, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), and is an electronic control unit that controls each part of the power control device 20, such as the inverter 21, the boost converter 22, the step-down converter 23, and the DC / DC converter 24.

[0037] More specifically, the MG-ECU 25 receives command signals and the like from the hybrid control ECU 50 and controls the on / off of each transistor included in the inverter 21 and the boost converter 22. The MG-ECU 25 also acquires detection results from the current sensors 211, 212 and the voltage sensors 265a to 265c and outputs them to the hybrid control ECU 50. The MG-ECU 25 also outputs an abnormality signal to the hybrid control ECU 50 when an abnormality is detected in each part of the power control device 20 including the transistors.

[0038] The DC / AC converter 40 is connected between the DC / DC converter 24 and the battery 30, and converts the direct current power from the battery 30 into alternating current (AC) power and outputs it, for example, to the interior of the vehicle. This makes it possible to use various devices, such as home appliances, that operate on AC power, inside the vehicle.

[0039] The hybrid control ECU (HEV-ECU) 50 serving as a vehicle control device is an electronic control unit that controls multiple drive sources, such as the power of the battery 30 and the power of an internal combustion engine, and is configured as a computer equipped with a CPU, ROM, RAM, etc.

[0040] In other words, the HEV-ECU 50 controls the vehicle to run solely on power from the motor 12, for example, when the vehicle is starting and at low speeds where the internal combustion engine is inefficient, and when accelerating rapidly, it obtains large acceleration force by using the driving forces of both the internal combustion engine and the motor 12.

[0041] Furthermore, when the system is shut down, for example when the vehicle ignition power is turned off, the HEV-ECU 50 outputs a command signal to the MG-ECU 25 of the power control device 20 to rapidly discharge the charge accumulated in the smoothing capacitor 262. At this time, the HEV-ECU 50 monitors, for example, via the MG-ECU 25, whether the discharge of the smoothing capacitor 262 is performed normally.

[0042] Furthermore, the HEV-ECU 50 determines whether or not to permit the system to start up depending on whether the smoothing capacitor 262 is normally discharged or not when the system is next started up, for example, when the ignition power is turned on again.

[0043] (Example of hybrid control ECU configuration) Next, a configuration example of the HEV-ECU 50 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of a hardware configuration of the HEV-ECU 50 according to the embodiment together with a peripheral configuration.

[0044] 2, the HEV-ECU 50 includes, as functional units, an input / output unit 51, a discharge control unit 52, a determination unit 53, a warning generation unit 54, and a storage unit 55. These functional units are realized by the CPU of the HEV-ECU 50 expanding a control program stored in the ROM, for example, into the RAM and executing the program, and by the ROM and RAM operating under the control of the CPU that executes the control program.

[0045] The input / output unit 51 is configured to be able to transmit and receive various signals between the HEV-ECU 50 and peripheral components such as the MG-ECU 25 provided in the power control device 20 and a display control ECU 60 that controls the display device 610.

[0046] For example, the input / output unit 51 acquires from the MG-ECU 25 detection results of current values ​​or voltage values ​​by the current sensors 211, 212 and the voltage sensors 265a to 265c included in the power control device 20. The input / output unit 51 also acquires from the MG-ECU 25 an abnormality signal indicating that some abnormality has occurred in the power control device 20. The input / output unit 51 also outputs to the MG-ECU 25 command signals generated by the discharge control unit 52, the determination unit 53, etc.

[0047] Also, for example, when the input / output unit 51 acquires an abnormality signal from the MG-ECU 25 indicating that an abnormality has occurred in the discharge of the smoothing capacitor 262 when the system is shut down, the input / output unit 51 outputs the warning generated by the warning generation unit 54 to the display control ECU 60.

[0048] The discharge control unit 52 generates a command signal for the MG-ECU 25 when the system is shut down, and rapidly discharges the charge accumulated in the smoothing capacitor 262. That is, when the MG-ECU 25 receives a command signal from the discharge control unit 52 via the input / output unit 51, it causes a current to flow through the d-axis of the motor 12 to consume power, thereby discharging the smoothing capacitor 262.

[0049] Here, motor 12 has a d-axis (direct axis) that is in the same direction as the magnetic field lines extending from the north pole to the south pole of the permanent magnet provided in motor 12, and a q-axis (quadrature axis) that is perpendicular to the d-axis.

[0050] Under normal circumstances, torque can be generated by passing a current through the q-axis of the motor 12 to rotate the motor 12. On the other hand, when a current is passed through the d-axis of the motor 12, no torque is generated, and power is consumed by converting electrical energy into thermal energy in the coil of an electromagnet provided in the motor 12, allowing the smoothing capacitor 262 to be discharged.

[0051] This rapid discharge of the smoothing capacitor 262 by passing a current through the d-axis of the motor 12 is also called active discharge. Such active discharge is performed so that, for example, a maintenance worker can access high voltage parts such as the smoothing capacitor 262 without the risk of electric shock after the system is shut down.

[0052] As described above, the power control device 20 includes the discharge circuit 2 including the smoothing capacitor 262 and the discharge resistor 261. Therefore, if active discharge is not performed normally due to some malfunction, power continues to be consumed in the discharge circuit 2 by the discharge resistor 261 even after the system is shut down, making it possible to gradually discharge the smoothing capacitor 262.

[0053] Discharging the smoothing capacitor 262 by power consumption in the discharge circuit 2 in this manner is also called passive discharging. However, while active discharging can discharge the smoothing capacitor 262 in, for example, a few seconds, passive discharging takes, for example, several minutes to discharge the smoothing capacitor 262.

[0054] Here, the MG-ECU 25 can detect that some malfunction has occurred in the active discharge when the voltage of the smoothing capacitor 262 does not become equal to or lower than a predetermined threshold within a predetermined time during the active discharge. The voltage of the smoothing capacitor 262 can be known from the detection result of a voltage sensor 262a that detects the inter-terminal voltage VH of the smoothing capacitor 262, for example.

[0055] Furthermore, if any malfunction occurs in the active discharge, the HEV-ECU 50 receives an abnormality signal from the MG-ECU 25 via the input / output unit 51 as described above.

[0056] When the discharge control unit 52 receives an abnormality signal indicating that a discharge abnormality has occurred during active discharge from the MG-ECU 25, it stores a record of the discharge abnormality during active discharge in the storage unit 55. Note that since such a discharge abnormality determination is performed after the system is shut down, more specifically, the record of the discharge abnormality is stored in a non-volatile memory such as a ROM.

[0057] However, such an abnormality determination is not made if it is known that the active discharge is not or cannot be executed due to control reasons, such as when the vehicle is traveling at a certain speed or more when a command signal for active discharge is received. In this case, the MG-ECU 25 does not output an abnormality signal in the first place, or even if the MG-ECU 25 outputs an abnormality signal, the discharge control unit 52 does not record it in the memory unit 55, and a discharge abnormality is not confirmed.

[0058] The next time the system is started, the determination unit 53 refers to the memory unit 55 to check whether or not a record of a discharge abnormality during active discharge has been stored. If there is no record of a discharge abnormality remaining in the memory unit 55, the determination unit 53 allows the system to start up.

[0059] On the other hand, if a record of a discharge abnormality remains in memory unit 55, determination unit 53 outputs a command signal to MG-ECU 25 via input / output unit 51 to read out the detection result of voltage sensor 262a of power control device 20. Based on the detection result of voltage sensor 262a, determination unit 53 determines whether or not to permit the system to start up.

[0060] When the warning generation unit 54 receives an abnormality signal indicating a discharge abnormality in active discharge from the MG-ECU 25, the warning generation unit 54 generates a warning indicating that a discharge abnormality has occurred in active discharge. Note that when an abnormality signal other than the above-mentioned discharge abnormality is received from the power control device 20, the warning generation unit 54 may generate a warning about that abnormality.

[0061] The display control ECU 60 is an electronic control unit that controls a display device 610 provided, for example, in the passenger compartment of a vehicle, and is configured as a computer including a CPU, a ROM, a RAM, etc. The display control ECU 60 causes the display device 610 to perform various displays based on command signals from the HEV-ECU 50.

[0062] As an example, when the display control ECU 60 receives a warning generated by the warning generation unit 54 from the input / output unit 51, it causes the display device 610 to display a warning that an abnormality, such as a discharge abnormality during active discharge, has occurred in the power control device 20.

[0063] The display device 610 is, for example, a liquid crystal display (LCD) or an organic electroluminescent display (OLED), and displays various information including the above warnings to the user of the vehicle.

[0064] The storage unit 55 stores the control program executed by the CPU of the HEV-ECU 50, and various control parameters necessary for the operation of the HEV-ECU 50. Furthermore, when an abnormality signal indicating a discharge abnormality in active discharge is received from the MG-ECU 25, the storage unit 55 stores a record of this discharge abnormality as described above. The record of the discharge abnormality is held in the storage unit 55 until it is erased by a maintenance worker, for example, by connecting a console to the HEV-ECU 50.

[0065] (Example of hybrid control ECU operation) Next, a detailed operation example of the HEV-ECU 50 of the embodiment will be described with reference to FIGS. 3A to 3C.

[0066] FIG. 3A is a diagram illustrating an example of an operation performed by the HEV-ECU 50 according to the embodiment when active discharging is normally performed.

[0067] 3A, when the system is shut down, for example when the ignition power is turned off, the discharge control unit 52 of the HEV-ECU 50 outputs a command signal for performing active discharge to the MG-ECU 25 via the input / output unit 51. In accordance with the command signal from the HEV-ECU 50, the MG-ECU 25 passes a current through the d-axis of the motor 12 to perform active discharge.

[0068] As a result, as shown by the voltage curve VHa due to active discharge in the figure, the terminal voltage VH of the smoothing capacitor 262 drops rapidly, and becomes equal to or lower than a predetermined threshold value TH, which is detected by, for example, the voltage sensor 265a.

[0069] Thereafter, the next time the system is started, for example when the ignition power is turned on, the determination unit 53 of the HEV-ECU 50 checks whether or not a record of a discharge abnormality in active discharge has been stored in the memory unit 55. In the example of Fig. 3A, the active discharge was performed normally the previous time the system was shut down, so no record of a discharge abnormality has been stored.

[0070] In this case, the HEV-ECU 50 permits the system to start up. As a result, the power output from the battery 30 and boosted by the boost converter 22 is supplied to the smoothing capacitor 262, and the generator 11 and the motor 12 start to be driven. Therefore, as shown by the voltage curve VHc due to the boost of the boost converter 22 in the figure, the voltage VH between the terminals of the smoothing capacitor 262 rapidly rises, which is detected by the voltage sensor 265a etc.

[0071] FIG. 3B is a diagram illustrating an example of an operation performed by the HEV-ECU 50 according to the embodiment when a discharge abnormality occurs during active discharge.

[0072] As shown in FIG. 3B, when the system is shut down, the discharge control unit 52 of the HEV-ECU 50 outputs a command signal to the MG-ECU 25 to perform active discharge, and the MG-ECU 25 passes a current through the d-axis of the motor 12 to perform active discharge.

[0073] At this time, it is assumed that some malfunction occurs in the power control device 20 and active discharge is not performed normally. In this case, as shown by the voltage curve VHa' due to active discharge in the figure, a rapid drop in the inter-terminal voltage VH of the smoothing capacitor 262 is not detected.

[0074] Based on the detection result of the voltage sensor 265 a, the MG-ECU 25 determines that a discharge abnormality has occurred in the active discharge, and outputs an abnormality signal to the HEV-ECU 50.

[0075] When the abnormality signal is received from the MG-ECU 25, the discharge control unit 52 stores a record of the occurrence of a discharge abnormality in active discharge in the memory unit 55. In addition, the warning generation unit 54 generates a warning of the occurrence of a discharge abnormality, and outputs it to the display control ECU 60 via the input / output unit 51. The display control ECU 60 causes the display device 610 to display the received warning.

[0076] 3B, it is assumed that passive discharge is normally performed by the discharge circuit 2 after the system is shut down. In other words, it is assumed that power is consumed by the discharge resistor 261 of the discharge circuit 2 and the smoothing capacitor 262 is discharged. As a result, as shown by the voltage curve VHp due to passive discharge in the figure, the terminal voltage VH of the smoothing capacitor 262 gradually decreases and becomes equal to or lower than a predetermined threshold value TH.

[0077] Thereafter, when the determination unit 53 of the HEV-ECU 50 refers to the storage unit 55 at the next system startup, in the example of FIG. 3B, a record of a discharge abnormality during active discharge is stored.

[0078] Therefore, determination unit 53 outputs a command signal for reading out the detection result of voltage sensor 265a to MG-ECU 25 via input / output unit 51. MG-ECU 25 obtains the detection result of voltage sensor 265a and outputs it to HEV-ECU 50 in accordance with the command signal from HEV-ECU 50.

[0079] The determination unit 53 determines whether or not the terminal voltage VH of the smoothing capacitor 262 is equal to or lower than the threshold value TH based on the detection result of the voltage sensor 265a. In the example of Fig. 3B, since the passive discharge was normally performed after the system was shut down, it is detected that the terminal voltage VH of the smoothing capacitor 262 is equal to or lower than the threshold value TH.

[0080] In this case, the determination unit 53 permits the system to start up. As a result, the smoothing capacitor 262 stores electricity, and as shown by the voltage curve VHc due to the boost of the boost converter 22 in the figure, the terminal voltage VH of the smoothing capacitor 262 rises rapidly, which is detected by the voltage sensor 265a etc.

[0081] FIG. 3C is a diagram illustrating another example of the operation performed by the HEV-ECU 50 according to the embodiment when a discharge abnormality occurs during active discharge.

[0082] As shown in FIG. 3A, when the system is shut down, the discharge control unit 52 of the HEV-ECU 50 outputs a command signal to the MG-ECU 25 to perform active discharge, and the MG-ECU 25 passes a current through the d-axis of the motor 12 to perform active discharge.

[0083] At this time, in the example of FIG. 3C, it is assumed that some malfunction occurs in the power control device 20, and the inter-terminal voltage VH of the smoothing capacitor 262 does not become equal to or lower than the threshold value TH, as shown by the voltage curve VHa' due to active discharge in the figure.

[0084] The MG-ECU 25 outputs an abnormality signal to the HEV-ECU 50, and the discharge control unit 52 of the HEV-ECU 50 stores a record of the discharge abnormality in the memory unit 55. The warning generation unit 54 generates a warning of the discharge abnormality, and the warning is displayed on the display device 610.

[0085] In the example of FIG. 3C, after the system is shut down, passive discharge by the discharge circuit 2 is not performed normally, and the inter-terminal voltage VH of the smoothing capacitor 262 remains high, as shown by the voltage curve VHp' due to passive discharge in the figure.

[0086] After that, when the determination unit 53 of the HEV-ECU 50 refers to the memory unit 55 at the next system startup, the determination unit 53 causes the MG-ECU 25 to output the detection result of the voltage sensor 265a.

[0087] Furthermore, the determination unit 53 determines that the inter-terminal voltage VH of the smoothing capacitor 262 exceeds the threshold value TH based on the detection result of the voltage sensor 265a. In this case, the determination unit 53 does not permit the system to start up.

[0088] Here, the abnormality in active discharge may be caused by a malfunction that occurs temporarily. As a temporary malfunction, a temporary disconnection may occur in an output line that outputs a command signal for active discharge from the HEV-ECU 50 to the MG-ECU 25, for example, due to poor contact of a connector or the like. Alternatively, a transition may occur in which the power control device 20 is temporarily in a state where it cannot receive a command signal for active discharge, for example, while being reset. Alternatively, a case may be assumed in which the power control device 20 does not receive a command signal for active discharge because the motor 12 is rotated from the outside by the rotation of the wheels, for example, while the vehicle is on a slope.

[0089] At the next system startup, even if a record of a discharge abnormality is stored, if the voltage of the smoothing capacitor 262 is equal to or lower than the threshold value TH, the determination unit 53 permits the system startup as described above. This prevents the system startup from being prohibited even in cases where active discharge occurs due to a temporary malfunction.

[0090] However, if the voltage of the smoothing capacitor 262 remains greater than the threshold value TH even at the next system startup due to, for example, the power control device 20 being in a continuous malfunction state, the determination unit 53 does not permit the system to start up, as described above. This ensures the safety of the vehicle user and maintenance workers.

[0091] On the other hand, even if some kind of failure other than a primary failure actually occurs in the mechanism related to the active discharge of the power control device 20, the system may be permitted to start up if the passive discharge is normally performed. However, even in this case, for example, a warning is repeatedly displayed at the time of system startup, so that the user of the vehicle or the like can become aware of the failure of the power control device 20.

[0092] (Example of processing by the hybrid control ECU) Next, an example of processing by the HEV-ECU 50 according to the embodiment will be described with reference to Fig. 4. Fig. 4 is a flow chart showing an example of a procedure of processing by the HEV-ECU 50 according to the embodiment.

[0093] 4, the determination unit 53 of the HEV-ECU 50 waits for a system startup operation such as turning on the ignition power (step S101). The determination unit 53 waits until the system startup operation is performed (step S101: No).

[0094] When the system startup operation is performed (step S101: Yes), the determination unit 53 refers to the storage unit 55 to check whether or not a record of a discharge abnormality in active discharge is stored (step S102).

[0095] If a record of a discharge abnormality remains (step S102: Yes), the determination unit 53 instructs the MG-ECU 25 to read out the detection result of the voltage sensor 265a (step S103).

[0096] When the detection result of the voltage sensor 265a is output from the MG-ECU 25, the determination unit 53 determines whether or not the voltage of the smoothing capacitor 262 is equal to or lower than the threshold value TH based on the detection result of the voltage sensor 265a (step S104).

[0097] If the voltage of the smoothing capacitor 262 is greater than the threshold value TH (step S104: No), the determination unit 53 ends the process without permitting the system to start up (step S111).

[0098] If the voltage of the smoothing capacitor 262 is equal to or lower than the threshold value TH (step S104: Yes), the determination unit 53 permits the system to start up (step S105).

[0099] Furthermore, when the memory unit 55 is referred to and no record of a discharge abnormality is found (step S102: No), the judgment unit 53 allows the system to start up (step S105) without performing processing such as steps S103, S104, and S111.

[0100] When the system is started, the discharge control unit 52 of the HEV-ECU 50 waits for a system shutdown operation, such as turning off the ignition power (step S106). The discharge control unit 52 waits until the system shutdown operation is performed (step S106: No).

[0101] When the system shutdown operation is performed (step S106: Yes), the discharge control unit 52 instructs the MG-ECU 25 to perform active discharge (step S107). The discharge control unit 52 also determines whether the active discharge has ended normally (step S108).

[0102] When an abnormality signal is output from the MG-ECU 25 and active discharge is not performed normally (step S108: No), the discharge control unit 52 stores a record of the discharge abnormality in the active discharge in the memory unit 55 (step S110). In addition, the warning generation unit 54 of the HEV-ECU 50 generates a warning of the discharge abnormality in the active discharge and outputs it to the display control ECU 60 via the input / output unit 51 (step S110). The output warning is displayed on the display device 610 under the control of the display control ECU 60.

[0103] If the active discharge has ended normally without an abnormality signal being output from the MG-ECU 25 (step S108: Yes), the processes of steps S109 and S110 are skipped.

[0104] This ends the processing by the HEV-ECU 50 of the embodiment.

[0105] (Overview) In vehicles such as hybrid vehicles that use electric power at least as part of the drive source, active discharge is performed to discharge the charge accumulated in smoothing capacitors, etc., when the system is shut down. This makes it possible to prevent vehicle users and maintenance workers from receiving electric shocks by accessing high-voltage parts.

[0106] During active discharge, if a discharge abnormality occurs, such as the voltage of the smoothing capacitor not dropping normally, a record of the discharge abnormality is stored in a memory unit or the like. In addition, the next time the system is started, the fail-safe function will prohibit the system from starting up. The record of the discharge abnormality is kept in the memory unit until it is deleted by a maintenance worker or the like.

[0107] Here, even if a discharge abnormality is detected, there are cases where no failure is found in the drive circuit, etc. It is assumed that such a discharge abnormality is due to a temporary malfunction, such as a temporary poor contact of a connector or a temporary inability to respond on the power control device 20 side. However, if the fail-safe function is activated even when a discharge abnormality occurs due to a temporary malfunction, the system cannot be started until, for example, a maintenance worker or the like erases the record of the discharge abnormality, which may lead to a breakdown on the road.

[0108] According to the HEV-ECU 50 of the embodiment, when the system is next started, if the voltage of the smoothing capacitor 262 is equal to or lower than the threshold value, the system is permitted to start even if a record of a discharge abnormality in active discharge is stored. This makes it possible to prevent the system start from being restricted due to a temporary malfunction. Therefore, it is possible to prevent the vehicle from breaking down on the road.

[0109] According to the HEV-ECU 50 of the embodiment, when the system is next started up, if a record of a discharge abnormality during active discharge is stored and the voltage of the smoothing capacitor 262 is greater than the threshold value, the system is not permitted to start up. This ensures the safety of the vehicle user and maintenance workers.

[0110] According to the HEV-ECU 50 of the embodiment, when the discharge control unit 52 detects a discharge abnormality during active discharge, a warning is generated to be displayed on the display device 610 provided in the vehicle. This makes it possible to inform the user of the vehicle that there is a possibility that some kind of malfunction has actually occurred in the power control device 20 or the like.

[0111] In the above embodiment, the possibility of system startup is determined based on the detection result of voltage sensor 265a, which detects the voltage of smoothing capacitor 262, among multiple voltage sensors 265a-265c included in power control device 20. However, a predetermined threshold may be set for each of multiple voltage sensors 265a-265c, and system startup may be permitted when the detection results of at least some of the voltage sensors are equal to or lower than the threshold, or when the detection results of all of these voltage sensors are equal to or lower than the threshold.

[0112] In the above embodiment, the HEV-ECU 50 that controls the vehicle, which is a hybrid vehicle, determines whether or not to start the system based on whether or not a discharge abnormality has been recorded and the actual voltage of the smoothing capacitor 262. However, the above configuration of the embodiment can also be applied to a vehicle control device that controls a vehicle that is driven exclusively by electricity, such as an electric vehicle (EV).

[0113] (Additional Note) Preferred aspects of the present invention will be described below.

[0114] (Appendix 1) According to one aspect of the present invention, A vehicle control device that controls a vehicle that uses electric power at least as part of a driving source, a discharge control unit that, in a drive circuit having a motor and a capacitor, performs active discharge by passing a current through a d-axis of the motor to discharge the capacitor when the system is shut down; a determination unit that determines whether or not to permit system startup at the next system startup, The discharge control unit is When a discharge abnormality is detected in the active discharge, a record of the discharge abnormality is stored in a memory unit; The determination unit is When the voltage of the capacitor is equal to or lower than a threshold value at the next system startup, the system startup is permitted even if the record of the discharge abnormality is stored. A vehicle control device is provided.

[0115] (Appendix 2) In the vehicle control device described in Supplementary Note 1, The determination unit is At the next system startup, if the record of the discharge abnormality is stored and the voltage of the capacitor is greater than the threshold value, startup of the system is not permitted.

[0116] (Appendix 3) In the vehicle control device according to the above-mentioned supplementary note 1 or supplementary note 2, The vehicle further includes a warning generating unit that generates a warning to be displayed on a display device provided in the vehicle when the discharge control unit detects a discharge abnormality during the active discharge.

[0117] (Appendix 4) In the vehicle control device according to any one of Supplementary Note 1 to Supplementary Note 3, The drive circuit includes: The power supply further includes a discharge circuit that performs passive discharge by discharging the capacitor through power consumption in an internal circuit even after the system has been shut down.

[0118] (Appendix 5) In the vehicle control device according to any one of Supplementary Note 1 to Supplementary Note 4, The drive circuit includes: The capacitor includes at least a voltage sensor for detecting a voltage of the capacitor. The determination unit is When the system is next started, if the discharge abnormality is recorded, it is determined whether or not to permit the system to start based on the detection result of the voltage sensor.

[0119] (Appendix 6) In the vehicle control device according to any one of Supplementary Note 1 to Supplementary Note 4, The drive circuit includes: The power supply further includes a plurality of voltage sensors including a voltage sensor for detecting a voltage of the capacitor, The determination unit is When the discharge abnormality record is stored at the next system startup, if all detection results of the multiple voltage sensors are equal to or lower than the threshold value, the system is permitted to start even if the discharge abnormality record is stored. [Explanation of symbols]

[0120] 1. Drive system 2 Discharge circuit 3. Drive circuit 11. Generator 12 Motor 20 Power control device 25 MG-ECU 30 Battery 50 Hybrid control ECU (HEV-ECU) 51 Input / output section 52 Discharge control unit 53 Judgment section 54 Warning generator 55 Storage section 60 Display control ECU 261 Discharge resistor 262 Smoothing capacitor 265a~265c Voltage Sensor 610 Display device

Claims

[Claim 1] A vehicle control device that controls a vehicle that uses electric power at least as part of a driving source, a discharge control unit for causing a current to flow through a d-axis of the motor to discharge the capacitor when the system is shut down, in a drive circuit having a motor and a capacitor; a determination unit that determines whether or not to permit system startup at the next system startup; a discharge circuit that performs passive discharge by discharging the capacitor through power consumption in an internal circuit that is composed of the capacitor and a discharge resistor, The discharge control unit is When a discharge abnormality is detected in the active discharge, a record of the discharge abnormality is stored in a memory unit; The determination unit is When the discharge abnormality is not recorded at the next system startup, the system startup is permitted. When the system is started next time, if the discharge abnormality is recorded, it is determined whether the voltage of the capacitor is equal to or lower than a threshold value. permitting the system to start up when the voltage of the capacitor is equal to or lower than a threshold value as a result of the determination; If the result of the determination is that the voltage of the capacitor exceeds a threshold value, startup of the system is not permitted. Vehicle control device.

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