Drive unit

Abstract

To ensure that the second control device can detect a short circuit abnormality in the inverter even when communication between the first control device and the second control device is interrupted.SOLUTION: A drive device includes a motor, an inverter that drives the motor by switching a plurality of switching elements, a power storage device connected to the inverter via a power line, a first control device that controls the inverter, and a second control device that communicates with the first control device. When the first control device detects a short circuit in the inverter, it transmits short circuit information related to the short circuit to the second control device. When the second control device receives short circuit information from the first control device, it determines that a short circuit in the inverter has occurred. The second control device also determines that a short circuit in the inverter has occurred when it detects both a communication interruption with the first control device and an absolute value of a current in the power storage device being equal to or greater than a predetermined value.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a drive device.

Background Art

[0002] Conventionally, as this type of drive device, there has been proposed one including an engine, a motor, an inverter that drives the motor, a battery connected to the inverter via a power line, a plurality of current sensors that detect the current of each phase of the motor, an MGECU that controls the inverter, and a hybrid ECU that communicates with the MGECU, and the MGECU determines at least a short circuit of one phase of the inverter based on information from the plurality of current sensors (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a drive device, when communication between the MGECU (first control device) and the hybrid ECU (second control device) is interrupted, that is, when the second control device cannot receive short - circuit abnormal information related to a short - circuit abnormality of the inverter from the first control device, it is an issue to make the second control device capable of detecting a short - circuit abnormality of the inverter. The main object of the drive device of the present disclosure is to enable the second control device to detect a short - circuit abnormality of the inverter even when communication between the first control device and the second control device is interrupted.

Means for Solving the Problems

[0005] The drive device of this disclosure employs the following means to achieve the main objective described above. The drive device of this disclosure comprises a motor, an inverter that drives the motor by switching a plurality of switching elements, a power storage device connected to the inverter via a power line, a first control device that controls the inverter, and a second control device that communicates with the first control device. The first control device transmits short-circuit abnormality information related to the short-circuit abnormality to the second control device when it detects a short-circuit abnormality in the inverter, and the second control device determines that a short-circuit abnormality has occurred in the inverter when it receives the short-circuit abnormality information from the first control device. The gist of the drive device is that the second control device also determines that a short-circuit abnormality has occurred in the inverter when it detects both a loss of communication with the first control device and the absolute value of the current in the power storage device being greater than or equal to a predetermined value.

[0006] In the drive system of this disclosure, when the first control unit detects a short-circuit anomaly in the inverter, it transmits short-circuit anomaly information related to the short-circuit anomaly to the second control unit, and the second control unit determines that a short-circuit anomaly has occurred in the inverter when it receives the short-circuit anomaly information from the first control unit. The second control unit also determines that a short-circuit anomaly has occurred in the inverter when it detects both a communication interruption with the first control unit and that the absolute value of the current in the energy storage device is greater than or equal to a predetermined value. When a short-circuit anomaly occurs in the inverter, a relatively large current flows through the energy storage device connected to the inverter via a power line. Therefore, through this process, the second control unit can detect a short-circuit anomaly in the inverter even when there is a communication interruption between the first and second control units, that is, when it cannot receive short-circuit anomaly information from the first control unit.

[0007] In the drive device of this disclosure, the detection of both conditions may include the detection of a communication interruption with the first control device while simultaneously detecting that the absolute value of the current in the energy storage device is equal to or greater than the predetermined value. Alternatively, the detection of both conditions may include the detection of a communication interruption with the first control device within a predetermined time period after detecting that the absolute value of the current in the energy storage device is equal to or greater than the predetermined value.

[0008] The drive device of the present disclosure further comprises a DC / DC converter that steps down the power of the power line and supplies it to a second power line, wherein the first control device controls the inverter so that the gate of the inverter is shut off when it determines that a short-circuit abnormality has occurred in the drive system, and the second control device stops the DC / DC converter when it determines that a short-circuit abnormality has occurred in the inverter and determines whether or not at least one of the plurality of switching elements is welded based on whether or not current is flowing in the power line. In this way, when the second control device detects a short-circuit abnormality in the inverter while communication between the first control device and the second control device is interrupted, the second control device can determine whether or not at least one of the plurality of switching elements of the inverter is welded. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a vehicle 20 equipped with the drive unit of the embodiment of the disclosure. [Figure 2] This is a schematic diagram of the high-voltage system of vehicle 20. [Figure 3] This flowchart shows an example of a processing routine executed by HVECU70. [Figure 4] This is a time chart showing an example of what happens when a short-circuit abnormality occurs in the inverter 32 while communication between the motor ECU 34 and HVECU 70 is interrupted. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of a vehicle 20 equipped with a drive system according to an embodiment of this disclosure, and Figure 2 is a schematic diagram of the high-voltage system of the vehicle 20. As shown in Figure 1, the vehicle 20 of the embodiment includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 24, a motor generator 30, an inverter 32, a motor electronic control unit (hereinafter referred to as "motor ECU") 34, a power transmission device 40, a high-voltage battery 50, a relay 54, a low-voltage battery 60, a DC / DC converter 64, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70. The engine ECU 24, motor ECU 34, and HVECU 70 can communicate with each other via a shared communication line (CAN bus) 90.

[0011] The engine 22 is an internal combustion engine that outputs power through four strokes: intake, compression, expansion (explosive combustion), and exhaust, using hydrocarbon fuels such as gasoline or diesel from a fuel tank. The crankshaft 23 of the engine 22 is connected to the torque converter 41 of the power transmission device 40.

[0012] The engine ECU 24 is equipped with a microcomputer, which has a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The engine ECU 24 receives signals from various sensors via its input ports. For example, the engine ECU 24 receives the crank angle θcr from the crank position sensor 23a, which detects the rotational position of the crankshaft 23 of the engine 22, and the coolant temperature from the coolant temperature sensor, which detects the coolant temperature of the engine 22. The engine ECU 24 outputs various control signals via its output ports. For example, the engine ECU 24 outputs control signals to the throttle valve, the fuel injection valve, and the spark plug. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 23a.

[0013] A starter 26 for cranking the engine 22 is connected to the crankshaft 23 of the engine 22. The starter 26 is connected to a low-voltage power line 62 along with a low-voltage battery 60, a DC / DC converter 64, and auxiliary equipment (not shown). A pulley 22a is also attached to the crankshaft 23 of the engine 22.

[0014] The motor-generator 30 is configured as a synchronous generator-motor and has a rotor with permanent magnets embedded in the rotor core and a stator with three-phase coils wound around the stator core. A pulley 30a is attached to the rotating shaft to which the rotor of the motor-generator 30 is mounted. A belt 28 is wrapped around the aforementioned pulleys 22a and 30a.

[0015] The inverter 32 is used to drive the motor generator 30. The inverter 32 is connected to the high-voltage power line 52 along with the high-voltage battery 50 and the DC / DC converter 64. As shown in Figure 2, the inverter 32 has six switching elements, transistors T11 to T16, and six diodes D11 to D16 connected in parallel to each of the six transistors T11 to T16. Transistors T11 to T16 can be, for example, IGBTs or MOSFETs. Transistors T11 to T16 are arranged in pairs, with two on each side, so as the source and sink sides with respect to the positive and negative lines of the high-voltage power line 52. Each connection point of a pair of transistors T11 to T16 is connected to each of the three-phase (U-phase, V-phase, W-phase) coils of the motor 32. Therefore, when voltage is applied to the inverter 32, the motor ECU 34 adjusts the ratio of the on-times of the paired transistors T11 to T16, thereby forming a magnetic field in the three-phase coil and driving the motor 32 in either a motorized or regenerative mode.

[0016] The motor ECU 34 is equipped with a microcomputer similar to the engine ECU 24. The motor ECU 34 receives signals from various sensors via input ports. For example, the motor ECU 34 receives the rotational position θm from the rotational position sensor 31a, which detects the rotational position of the rotor of the motor generator 30, and the phase currents Iu, Iv, and Iw from the current sensors 31u, 31v, and 31w, which detect the phase currents of each phase of the motor generator 30. The motor ECU 34 outputs control signals to the transistors T11 to T16 of the inverter 32 via output ports. The motor ECU 34 calculates the electrical angle θe and rotational speed Nm of the motor generator 30 based on the rotational position θm of the rotor of the motor generator 30 from the rotational position sensor 31a.

[0017] The power transmission system 40 comprises a torque converter 41 and an automatic transmission 42. The torque converter 41 is configured as a general fluid transmission device and includes a pump impeller connected to the crankshaft 23 of the engine 22, a turbine runner connected to the input shaft of the automatic transmission 42, a stator that rectifies the flow of hydraulic fluid from the turbine runner to the pump impeller, a one-way clutch that restricts the rotation direction of the stator to one direction, and a hydraulically driven lock-up clutch that connects and disconnects the pump impeller and the turbine runner. The torque converter 41 transmits power from the engine 22 to the input shaft of the automatic transmission 42 with or without torque amplification. The automatic transmission 42 is configured as, for example, a 4-speed to 10-speed automatic transmission and includes an input shaft, an output shaft, at least one planetary gear mechanism, and a plurality of hydraulically driven friction engagement elements (clutches and brakes). The input shaft is connected to the torque converter 41, and the output shaft is connected to the drive shaft 46, which is connected to the drive wheel DW via the drive shaft DS and differential gear DF. The automatic transmission 42 transmits the power transmitted from the torque converter 41 to the input shaft in multiple stages to the output shaft. The automatic transmission may be, for example, a continuously variable transmission (CVT) or a dual-clutch transmission.

[0018] The high-voltage battery 50 is configured as, for example, a lithium-ion battery or a nickel-metal hydride battery, and as described above, is connected to the high-voltage power line 52 together with the inverter 32. The relay 54 is provided in the high-voltage power line 52 and connects and disconnects the inverter 32 side and the high-voltage battery 50 side. The low-voltage battery 60 is configured as, for example, a lead-acid battery with a rated voltage lower than that of the high-voltage battery 50, and as described above, is connected to the low-voltage power line 62 together with the starter 26 and auxiliary equipment.

[0019] The DC / DC converter 64 is connected to the inverter 32 side of the relay 54 on the high-voltage power line 52 and to the low-voltage power line 62. The DC / DC converter 64 steps down the power from the high-voltage power line 52 and supplies it to the low-voltage power line 62.

[0020] The HVECU 70 includes a microcomputer similar to the engine ECU 24. The HVECU 70 inputs signals from various sensors via input ports. For example, the HVECU 70 inputs the rotational speed Nt1 from a rotational speed sensor that detects the rotational speed of the input shaft of the power transmission device 40 (the input side of the torque converter), the rotational speed Nt2 from a rotational speed sensor that detects the rotational speed of the input shaft of the automatic transmission, and the rotational speed Nt3 from a rotational speed sensor that detects the rotational speed of the output shaft of the automatic transmission. The HVECU 70 also inputs the voltage Vb1 from the voltage sensor 51a attached between the terminals of the high-voltage battery 50, the current Ib1 from the current sensor 51b attached to the output terminal of the high-voltage battery 50, the voltage Vb2 from the voltage sensor 61a attached between the terminals of the low-voltage battery 60, and the current Ib2 from the current sensor 61b attached to the output terminal of the low-voltage battery 60. The HVECU 70 inputs the high-voltage system voltage VH from a voltage sensor attached to the high-voltage system power line 52 and the low-voltage system voltage VL from a voltage sensor attached to the low-voltage system power line 62. The HVECU 70 inputs the start signal from the start switch 80, the shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed V from the vehicle speed sensor 87.

[0021] The HVECU70 outputs various control signals via its output ports. For example, the HVECU70 outputs control signals to the starter 26, the power transmission device 40, the relay 54, and the DC / DC converter 64. The HVECU70 calculates the charge level (SOC1) of the high-voltage battery 50 based on the integrated value of the current Ib1 of the high-voltage battery 50 from the current sensor 51b and the voltage Vb1 of the high-voltage battery 50 from the voltage sensor 51a, and calculates the charge level (SOC2) of the low-voltage battery 60 based on the integrated value of the current Ib2 of the low-voltage battery 60 from the current sensor 61b and the voltage Vb2 of the low-voltage battery 61 from the voltage sensor 61a.

[0022] In the vehicle 20 of the embodiment, the HVECU 70 sets the target gear position Gs* of the automatic transmission 42 of the power transmission device 40 based on the accelerator opening Acc and vehicle speed V, and controls the power transmission device 40 so that the gear position Gs of the automatic transmission 42 becomes the target gear position Gs*. The HVECU 70 also sets the required torque Td* required for the input shaft of the automatic transmission 42 based on the accelerator opening Acc, vehicle speed V and the gear position Gs of the automatic transmission 42, and sets the torque command Tm* of the motor generator 30 based on the charge / discharge required power Pb* of the high-voltage battery 50 based on the charge level SOC1 of the high-voltage battery 50. The charge / discharge required power Pb* is set so that the charge level SOC approaches the control center SOC*. Next, the system sets the required torque Te* for the engine 22 based on the requested torque Td* and the torque command Tm* of the motor generator 30, and transmits the required torque Te* to the engine ECU 24 and the torque command Tm* to the motor ECU 34. The engine ECU 24 controls the operation of the engine 22 (such as intake air volume control, fuel injection control, and ignition control) so that the engine 22 is driven based on the target torque Te*. The motor ECU 34 controls the switching of transistors T11 to T16 of the inverter 32 so that the motor generator 30 is driven by the torque command Tm*.

[0023] In the vehicle 20 of the embodiment, when the motor ECU 34 detects a short-circuit abnormality (abnormality in which some phases are short-circuited) of the inverter 32 through the short-circuit abnormality determination process, it sets the value 1 in the short-circuit abnormality flag Fscmg, executes the gate cutoff process of the inverter 32, and transmits short-circuit abnormality information related to the short-circuit abnormality of the inverter 32 (for example, information that the short-circuit abnormality flag Fscmg has the value 1) to the HV ECU 70. Here, in the short-circuit abnormality determination process, the motor ECU 34 determines that a short-circuit abnormality of the inverter 32 has occurred (detects the short-circuit abnormality of the inverter 32) when, for example, the absolute value of any of the phase currents Iu, Iv, Iw of each phase of the motor generator 30 satisfies the first motor current condition of being not less than the threshold value Imref1 over a predetermined time Tp11. In the gate cutoff process of the inverter 32, the motor ECU 34 controls the inverter 32 so that the inverter 32 is gate-cut off (specifically, all of the transistors T11 to T16 are turned off).

[0024] After starting the gate cutoff process of the inverter 32, the motor ECU 34 executes a welding determination process, and when the welding determination process ends, it transmits a welding determination process end signal to the HV ECU 70. When receiving the welding determination process end signal, the HV ECU 70 turns off the relay 54. Here, in the welding determination process, the motor ECU 34 determines that at least one of the transistors T11 to T16 of the inverter 32 (the transistor that caused the short-circuit abnormality) is welded (on-failure) when, for example, the absolute value of any of the phase currents Iu, Iv, Iw of each phase of the motor generator 30 satisfies the second motor current condition of being not less than the threshold value Imref2 over a predetermined time Tp12 at the welding determination time, and determines that none of the transistors T11 to T16 of the inverter 32 are welded (for example, the transistor that caused the short-circuit abnormality has an off-failure) when the second motor current condition is not satisfied.

[0025] Next, the operation of the drive unit mounted on the vehicle 20 of the embodiment will be described. Figure 3 is a flowchart of an example of a processing routine executed by the HVECU 70. This routine is executed repeatedly when no short-circuit abnormality is detected in the inverter 32. When this routine is executed, the HVECU 70 first inputs the communication interruption flag Fcd and the high current flag Fi (step S100).

[0026] Here, the communication interruption flag Fcd is input to the value set by the communication interruption flag setting process executed by HVECU70. In the communication interruption flag setting process, HVECU70 sets the value of the communication interruption flag Fcd to 0 when it has not detected a communication interruption with the motor ECU34, and sets the value of the communication interruption flag Fcd to 1 when it has detected a communication interruption with the motor ECU34. HVECU70 detects a communication interruption with the motor ECU34 when it does not receive a response signal from the motor ECU34 within a predetermined time Tp21 after sending a response request signal to the motor ECU34, or when it does not receive any signal from the motor ECU34 for a predetermined time Tp22. For example, the predetermined time Tp22 may be approximately the same as the predetermined time Tp21.

[0027] The high-current flag Fi is input to a value set by the high-current flag setting process executed by the HVECU 70. In the high-current flag setting process, the HVECU 70 sets the high-current flag Fi to an initial value of 0 when the start switch 80 is turned on, sets the high-current flag Fi to a value of 1 (switches from value 0 to value 1) when the first battery current condition is met, in which the absolute value of the current Ib1 of the high-voltage battery 50 is greater than or equal to the threshold Ibref1 for a predetermined time Tp31, and then sets the high-current flag Fi to a value of 0 (switches from value 1 to value 0) after a predetermined time Tp32 has elapsed. As mentioned above, when the motor ECU 34 detects a short-circuit abnormality in the inverter 32, it executes gate tripping processing for the inverter 32. As a result, it is assumed that the absolute value of the current Ib1 of the high-voltage battery 50 connected to the inverter 32 via the high-voltage power line 52 will also decrease.

[0028] If the communication interruption flag Fcd or the high current flag Fi is input in step S100, it is determined whether the communication interruption flag Fcd is valued at 1 (step S110), and whether the high current flag Fi is valued at 1 (step S120). If it is determined in step S110 that the communication interruption flag Fcd is valued at 0, or if it is determined in step S120 that the high current flag Fi is valued at 0, this routine is terminated.

[0029] If the communication interruption flag Fcd is determined to be value 1 in step S110 and the high current flag Fi is determined to be value 1 in step S120, then it is determined that a short-circuit abnormality has occurred in the inverter 32 (a short-circuit abnormality in the inverter 32 is detected), and the short-circuit abnormality flag Fschv is set to value 1 (step S130). Here, when both the communication interruption flag Fcd and the high current flag Fi are value 1, it is assumed that the HVECU 70 has detected a communication interruption with the motor ECU 34 and that the absolute value of the current Ib1 of the high-voltage battery 50 is greater than or equal to the threshold Ibref1, or that the HVECU 70 has detected a communication interruption with the motor ECU 34 within a predetermined time Tp32 after detecting that the absolute value of the current Ib1 of the high-voltage battery 50 is greater than or equal to the threshold Ibref1.

[0030] When communication is interrupted between the HVECU70 and the motor ECU34, even if the motor ECU34 detects a short-circuit anomaly in the inverter 32, the HVECU70 cannot receive short-circuit anomaly information from the motor ECU34. Incidentally, when a short-circuit anomaly occurs in the inverter 32, the absolute value of the phase current of some phases of the motor generator 30 and inverter 32 (for example, the phase current Iu of the U phase) increases, and it is assumed that the absolute value of the current Ib1 of the high-voltage battery 50 connected to the inverter 32 via the high-voltage power line 52 also increases. Based on these considerations, in this embodiment, the HVECU 70 determines that a short-circuit abnormality has occurred in the inverter 32 (detects a short-circuit abnormality in the inverter 32) when the communication interruption flag Fcd is valued at 1 and the high-current flag Fi is valued at 1, specifically when it detects a communication interruption with the motor ECU 34 and the absolute value of the current Ib1 of the high-voltage battery 50 is greater than or equal to the threshold Ibref1, or when it detects a communication interruption with the motor ECU 34 within a predetermined time Tp32 after detecting that the absolute value of the current Ib1 of the high-voltage battery 50 is greater than or equal to the threshold Ibref1. As a result, the HVECU 70 can detect a short-circuit abnormality in the inverter 32 even when a communication interruption with the motor ECU 34 occurs, that is, when it cannot receive short-circuit abnormality information from the motor ECU 34.

[0031] Next, the DC / DC converter 64 is stopped (step S140), and a predetermined time Tp41 is waited for to elapse (step S150). Here, the predetermined time Tp41 is set in advance as the time required to de-excite the DC / DC converter 64 when none of the transistors T11 to T16 of the inverter 32 are welded (for example, when the transistor that caused the short circuit malfunction has turned off).

[0032] Then, it is determined whether or not current is flowing through the high-voltage power line 52 (step S170). In this determination process, for example, if the second battery current condition is met during the current determination time, where the absolute value of the current Ib1 of the high-voltage battery 50 connected to the high-voltage power line 52 is greater than or equal to a threshold Ibref2 for a predetermined time Tp51, it is determined that current is flowing through the high-voltage power line 52. If the second battery current condition is not met, it is determined that no current is flowing through the high-voltage power line 52.

[0033] If it is determined in step S170 that current is flowing through the high-voltage power line 52, it is determined that at least one of the transistors T11 to T16 of the inverter 32 (the transistor that caused the short-circuit malfunction) is welded (on-fault). In this case, the welded flag Fwl is set to value 1 (step S180), the relay 54 is turned off (step S190), and this routine is terminated. If it is determined in step S170 that no current is flowing through the high-voltage power line 52, it is determined that none of the transistors T11 to T16 of the inverter 32 are welded (for example, the transistor that caused the short-circuit malfunction has turned off). In this case, the processing in step S180 is skipped (the welded determination flag Fwl is kept at value 0), the relay 54 is turned off (step S190), and this routine is terminated. These processes allow the HVECU70 to determine whether or not at least one of the transistors T11 to T16 of the inverter 32 is welded together when communication between the motor ECU34 and the HVECU70 is interrupted and the HVECU70 detects a short-circuit abnormality in the inverter 32.

[0034] Figure 4 is a time chart showing an example of what happens when a short-circuit anomaly occurs in the inverter 32 while communication between the motor ECU 34 and the HVECU 70 is interrupted. Figure 4 shows the short-circuit anomaly flag Fscmg, whether or not the inverter 32's gate-cutting process is executed, whether or not communication between the motor ECU 34 and the HVECU 70 is interrupted, the absolute value of the high-voltage battery 50's current Ib1, the communication interruption flag Fcd, the high-current flag Fi, the short-circuit anomaly flag Fschv, the drive / stop of the DC / DC converter 64, and the welding flag Fwl. The presence or absence of communication interruption between the motor ECU 34 and the HVECU 70, and the absolute value of the high-voltage battery 50's current Ib1 are events (phenomena), the short-circuit anomaly flag Fscmg and whether or not the inverter 32's gate-cutting process is executed are related to the motor ECU 34's processing, and the communication interruption flag Fcd, the high-current flag Fi, the short-circuit anomaly flag Fschv, the drive / stop of the DC / DC converter 64, and the welding flag Fwl are related to the HVECU 70's processing.

[0035] As shown in the figure, at time t12, when the motor ECU 32 detects a short-circuit anomaly in the inverter 32 due to the fulfillment of the first motor current condition based on the absolute values ​​of the phase currents Iu, Iv, and Iw of each phase of the motor generator 30, it switches the short-circuit anomaly flag Fscmg from value 0 to value 1, executes gate tripping processing for the inverter 32, and attempts to send the short-circuit anomaly information to the HVECU 70. However, since communication between the motor ECU 34 and the HVECU 70 has been lost since time t10, before time t12, the HVECU 70 cannot receive the short-circuit anomaly information. At time t11, after time t10, the HVECU 70 switches the high-current flag Fi from value 0 to value 1 when the first battery current condition based on the absolute value of the current Ib1 of the high-voltage battery 50 is fulfilled. At this time, the HVECU 70 has not detected (confirmed) the communication loss with the motor ECU 34, and the communication loss flag Fcd is value 0, so it holds the short-circuit anomaly flag Fschv at value 0. At time t13, when the HVECU 70 detects a communication interruption with the motor ECU 34, it switches the communication interruption flag Fcd from value 0 to value 1, and, given that both the high current flag Fi and the communication interruption flag Fsc are value 1, it determines that a short-circuit abnormality has occurred in the inverter 32, and switches the short-circuit abnormality flag Fschv from value 0 to value 1. In this way, the HVECU 70 can detect a short-circuit abnormality in the inverter 32 even when there is a communication interruption with the motor ECU 34, that is, when it cannot receive short-circuit abnormality information from the motor ECU 34. Then, the HVECU 70 stops the DC / DC converter 64, and at time t14, when it determines that current is flowing in the high-voltage power line 52, it determines that welding (on failure) has occurred in at least one of the transistors T11 to T16 of the inverter 32 (the transistor that caused the short-circuit abnormality), and switches the welding flag Fwl from value 0 to value 1. In this way, welding of at least one of the transistors T11 to T16 can be detected.

[0036] In the drive unit mounted on the vehicle 20 of this embodiment described above, the HVECU 70 determines that a short-circuit abnormality has occurred in the inverter 32 when the communication interruption flag Fcd is valued at 1 and the high current flag Fi is valued at 1, specifically when it detects a communication interruption with the motor ECU 34 and detects that the absolute value of the current Ib1 of the high-voltage battery 50 is greater than or equal to the threshold Ibref1, or when it detects a communication interruption with the motor ECU 34 within a predetermined time Tp32 after detecting that the absolute value of the current Ib1 of the high-voltage battery 50 is greater than or equal to the threshold Ibref1. As a result, the HVECU 70 can detect a short-circuit abnormality in the inverter 32 even when a communication interruption with the motor ECU 34 occurs, that is, when it cannot receive short-circuit abnormality information from the motor ECU 34.

[0037] Furthermore, in the drive unit mounted on the vehicle 20 of the embodiment, when the HVECU 70 determines that a short-circuit abnormality has occurred in the inverter 32 because the communication interruption flag Fcd is valued at 1 and the high-current flag Fi is valued at 1, it stops the DC / DC converter 64 and determines whether at least one of the transistors T11 to T16 of the inverter 32 is welded together based on whether or not current is flowing through the high-voltage power line 52. In this way, when a short-circuit abnormality in the inverter 32 is detected while communication between the motor ECU 34 and the HVECU 70 is interrupted, the HVECU 70 can determine whether at least one of the transistors T11 to T16 of the inverter 32 is welded together.

[0038] In the embodiment described above, when it is determined that a short-circuit abnormality has occurred in the inverter 32 because the communication interruption flag Fcd is valued at 1 and the high current flag Fi is valued at 1, the DC / DC converter 64 is stopped, it is determined whether or not at least one of the transistors T11 to T16 of the inverter 32 is welded together, and then the relay 54 is turned off. However, in this case, the relay 54 may be turned off without determining whether or not at least one of the transistors T11 to T16 of the inverter 32 is welded together.

[0039] In the embodiment described above, the engine 22 and the motor generator 30 were connected by a belt mechanism consisting of two pulleys 22a and 30a and a belt 28. However, the engine 22 and the motor generator 30 may also be connected by a chain mechanism, a gear mechanism, or directly connected.

[0040] In the embodiment described above, the motor generator 30 and inverter 32 are three-phase, but other phases, such as five-phase, may also be used.

[0041] In the above-described embodiment, a high-voltage battery 50 was used as the first energy storage device, but a capacitor or the like may be used instead or in addition to it. A low-voltage battery 60 was used as the second energy storage device, but a capacitor or the like may be used instead or in addition to it.

[0042] In the embodiment described above, the drive unit mounted on the vehicle 20 includes an engine ECU 24, a motor ECU 34, and an HVECU 70, but the engine ECU 24 and the HVECU 70 may be formed as a single unit. That is, it is sufficient to have a configuration that includes a first control device for controlling the inverter that drives the motor, and a second control device for communicating with the first control device.

[0043] In the embodiment described above, the drive system mounted on the vehicle 20 is configured such that the engine 22 is connected to the drive wheel DW via a power transmission device 40, the motor generator 30 is connected to the engine 22 via pulleys 22a, 30a and belt 28, and the inverter 32 that drives the motor generator 30 is connected to the high-voltage battery 50 via a high-voltage power line 52. However, it is not limited to this configuration, and any system comprising a motor, an inverter that drives the motor by switching of a plurality of switching elements, and a power storage device connected to the inverter via a power line is acceptable. For example, the motor may be connected to the drive wheel via a power transmission device, the engine may be connected to the motor via a clutch, and the power storage device may be connected to the inverter that drives the motor via a power line. Alternatively, the engine and the first motor may be connected to the drive wheel via planetary gears, the second motor may be connected to the drive wheel, and the power storage device may be connected to the first and second inverters that drive the first and second motors, respectively, via a common power line. Furthermore, a motor may be connected to the drive wheels, and a power storage device may be connected to the inverter that drives the motor via a power line.

[0044] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be explained. In the embodiment, the motor generator 30 corresponds to the "motor", the inverter 32 corresponds to the "inverter", the high-voltage battery 50 corresponds to the "energy storage device", the motor ECU 40 corresponds to the "first control device", and the engine ECU 24 and HVECU 70 correspond to the "second control device".

[0045] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0046] While embodiments for implementing this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0047] This disclosure can be used in industries such as the manufacturing of drive systems. [Explanation of Symbols]

[0048] 20 Vehicle, 30 Motor Generator, 31a Rotation Position Sensor, 31u, 31v, 31w Current Sensor, 32 Inverter, 34 Motor ECU, 40 Power Transmission, 41 Torque Converter, 42 Automatic Transmission, 46 Drive Shaft, 50 High Voltage Battery, 51a Voltage Sensor, 51b Current Sensor, 52 High Voltage Power Line, 54 Relay, 60 Low Voltage Battery, 61a Voltage Sensor, 61b Current Sensor, 62 Low Voltage Power Line, 64 DC / DC Converter, 70 HVECU, 80 Start Switch, 81 Shift Lever, 82 Shift Position Sensor, 83 Accelerator Pedal, 84 Accelerator Pedal Position Sensor, 85 Brake Pedal, 86 Brake Pedal Position Sensor, 87 Vehicle Speed ​​Sensor, D11~D16 Diodes, T11~T16 Transistors.

Claims

1. The system comprises a motor, an inverter that drives the motor by switching multiple switching elements, a power storage device connected to the inverter via a power line, a first control device that controls the inverter, and a second control device that communicates with the first control device. When the first control device detects a short-circuit abnormality in the inverter, it transmits short-circuit abnormality information related to the short-circuit abnormality to the second control device. The second control device, upon receiving the short-circuit abnormality information from the first control device, determines that a short-circuit abnormality has occurred in the inverter. A drive device, The second control device also determines that a short-circuit abnormality has occurred in the inverter when it detects both a loss of communication with the first control device and the absolute value of the current in the energy storage device being greater than or equal to a predetermined value. Drive unit.

2. A drive device according to claim 1, When both of the above detections occur, it includes the case when a communication interruption with the first control device is detected and the absolute value of the current in the energy storage device is detected to be equal to or greater than the predetermined value, Drive unit.

3. A drive device according to claim 1, The above-mentioned detections include the detection of a communication interruption with the first control device within a predetermined time after detecting that the absolute value of the current of the energy storage device is equal to or greater than the predetermined value, Drive unit.

4. A drive device according to any one of claims 1 to 3, The system further includes a DC / DC converter that steps down the power of the aforementioned power line and supplies it to a second power line. When the first control device determines that a short-circuit abnormality has occurred in the drive system, it controls the inverter so that the gate of the inverter is shut off. When the second control device determines that a short-circuit abnormality has occurred in the inverter, it stops the DC / DC converter and determines whether at least one of the plurality of switching elements is welded together based on whether or not current is flowing in the power line. Drive unit.

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