Control device for vehicle

Abstract

To identify a place where abnormality occurs, in a circuit including a motor, an inverter, a battery and a DC / DC converter.SOLUTION: A control device for a vehicle which is used in a vehicle including a motor for traveling, an inverter for driving the motor, a battery which is connected to a first power line that is a power line of the inverter and exchanges power with the motor, and a DC / DC converter which is connected to the first power line through a second power line and converts a voltage from the battery, and controls the motor, the inverter and the DC / DC converter, wherein the vehicle includes a first voltage sensor for detecting a voltage of the first power line, and a second voltage sensor for detecting a voltage of the second power line, and identifies a place where abnormality occurs in a circuit including the motor, the inverter, the battery and the DC / DC converter, on the basis of at least the voltages of the first and second voltage sensors.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, as this type of vehicle control device, one proposed for use in a vehicle equipped with a motor for driving, an inverter for driving the motor, a battery connected to a first power line which is a power line of the inverter and exchanging power with the motor, and a DC / DC converter connected to the first power line via a second power line and converting the voltage from the battery (see, for example, Patent Document 1). In this device, when an abnormality occurs in the battery, batteryless control is performed in which power generated by the motor is used to supply power to auxiliary devices connected to the DC / DC converter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-136973 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned documents do not disclose how to identify the location of an abnormality in a circuit including a motor, an inverter, a battery, and a DC / DC converter. It is recognized that it is an important issue to properly identify the location of an abnormality in such a circuit.

[0005] The main purpose of the vehicle control device disclosed herein is to identify the location where an abnormality has occurred in a circuit including a motor, an inverter, a battery, and a DC / DC converter. [Means for solving the problem]

[0006] The vehicle control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The vehicle control device disclosed herein is used in a vehicle including a motor for driving, an inverter for driving the motor, a battery connected to a first power line which is a power line of the inverter and exchanging power with the motor, and a DC / DC converter connected to the first power line via a second power line and converting voltage from the battery, and is a vehicle control device that controls the motor, the inverter, and the DC / DC converter, wherein the vehicle includes a first voltage sensor that detects the voltage of the first power line and a second voltage sensor that detects the voltage of the second power line, and the vehicle control device identifies the location where an abnormality has occurred in a circuit including the motor, the inverter, the battery, and the DC / DC converter based on at least the voltages of the first and second voltage sensors. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing the outline of the configuration of an electric drive system 20. [Diagram 2] 11 is a flowchart showing an example of a start-up determination process. [Diagram 3] 5 is a flowchart showing an example of a process to be performed when a voltage is abnormal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of an electric drive system 20 provided in a vehicle equipped with a vehicle control device of the present embodiment. The electric drive system (circuit) 20 of the present embodiment is mounted on a vehicle having an engine that outputs power to a drive shaft connected to an axle, and includes a motor 32, an inverter 34, a high-voltage battery 36, a DC / DC converter 50, and an electronic control unit (hereinafter referred to as "ECU") 60 as shown in the figure.

[0010] The motor 32 is configured as a synchronous generator motor, and has a rotor with a permanent magnet embedded in the rotor core, and a stator with a three-phase coil wound around the stator core. The rotor of the motor 32 may be connected to the output shaft of the engine, or may be connected to a drive shaft that is connected to the drive wheels via a differential gear.

[0011] The inverter 34 is used to drive the motor 32 and is connected to a first power line 42 on the high voltage side. The inverter 34 has six transistors T11-T16 as switching elements and six diodes D11-D16 connected in parallel to the six transistors T11-T16, respectively. The transistors T11-T16 are arranged in pairs, two at a time, so as to be on the source side and the sink side of the positive and negative lines of the first power line 42, respectively. Also, each of the three-phase coils (coils of U-phase, V-phase, and W-phase) of the motor 32 is connected to each of the connection points of two paired transistors of the transistors T11-T16. Therefore, when a voltage is applied to the inverter 34, the ECU 60 adjusts the ratio of the on time of the paired transistors T11-T16, thereby forming a rotating magnetic field in the three-phase coils, and the motor 32 is driven to rotate. A smoothing capacitor 46 is attached to the positive and negative lines of the first power line 42.

[0012] The high-voltage battery 36 is configured as, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery. The high-voltage battery 36 is connected to the first power line 42 via a system main relay SMR.

[0013] The DC / DC converter 50 is connected to the second power line 44 on the high voltage side and the third power line 52 on the low voltage side, which are connected between the system main relay SMR of the first power line 42 and the capacitor 46. The DC / DC converter 50 is controlled by the ECU 60 to step down the power of the second power line 44 and supply it to the third power line 52, or to step up the power of the third power line 52 and supply it to the second power line 44. A smoothing capacitor 48 is attached to the positive and negative lines of the second power line 44. A low-voltage battery 54 having a rated voltage lower than that of the high-voltage battery 36 is connected to the third power line 52.

[0014] Although not shown, the ECU 60 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. Examples of signals input to the ECU 60 include a rotational position θm from a rotational position sensor (e.g., a resolver) that detects the rotational position of the rotor of the motor 32, phase currents Iv and Iw from a current sensor that detects the phase currents of each phase of the motor 32, a voltage Vb from a voltage sensor 36a attached between the terminals of the high-voltage battery 36, a current Ib from a current sensor 36b attached to an output terminal of the high-voltage battery 36, a voltage Vinv of the first power line 42 (capacitor 46) from a voltage sensor (first voltage sensor) 46a attached to the first power line 42 (between the terminals of the capacitor 46), and a voltage Vdc of the second power line 44 (capacitor 48) from a voltage sensor (second voltage sensor) 48a attached to the second power line 44 (between the terminals of the capacitor 48). Various control signals are output from the ECU 60 via the output port. Examples of signals output from the ECU 60 include switching control signals to the transistors T11-T16 of the inverter 34, a control signal to the DC / DC converter 50, and a control signal to the system main relay SMR. The ECU 60 calculates the electrical angle θe and rotation speed Nm of the motor 32 based on the rotational position θm of the rotor of the motor 32 from the rotational position detection sensor 32a, and calculates the power storage ratio SOC of the high-voltage battery 36 based on an integrated value of the current Ib of the high-voltage battery 36 from the current sensor 36b. The power storage ratio SOC is the ratio of the amount of power stored in the high-voltage battery 36 (amount of dischargeable power) to the total capacity of the high-voltage battery 36.

[0015] In the electric drive system 20 of this embodiment configured as described above, when braking the vehicle equipped with the electric drive system 20, the ECU 60 executes charging control to control the switching of the transistors T11-T16 of the inverter 34 and to control the DC / DC converter 50 so that the high-voltage battery 36 and the low-voltage battery 54 are charged with power generated by the motor 32. When the vehicle equipped with the electric drive system 20 is traveling and the power output from a driving power source other than the motor 32, such as an engine, is insufficient for the power required by the vehicle, the ECU 60 executes assist control to control the inverter 34 so that the insufficient power is output from the motor 32 to the output shaft or drive shaft of the engine to which the rotor is connected.

[0016] Next, a description will be given of the operation of the electric drive system 20 of this embodiment configured as described above, in particular the operation for identifying the location of an abnormality caused by a break in the first and second power lines 42, 44. First, a description will be given of the operation for identifying the location of an abnormality caused by a break in the first and second power lines 42, 44 when the system is started and the system main relay SMR is switched from off to on. Next, a description will be given of the operation for identifying the location of an abnormality caused by a break in the first power line 42 or an abnormality in the voltage sensor 46a when a voltage abnormality occurs in which the voltage Vinv detected by the voltage sensor 46a exceeds the upper limit voltage Vmax of the normal voltage range after the system is started.

[0017] 2 is a flowchart showing an example of a start-up determination process executed by the ECU 60. This routine is executed when an ignition switch (not shown) is turned on to issue an instruction to start the system, with the vehicle system stopped and the system main relay SMR turned off. When the vehicle system is stopped and the system main relay SMR is turned off, the capacitors 46, 48 are discharged, and the voltages Vinv, Vdc detected by the voltage sensors 46a, 48a are zero.

[0018] When this routine is executed, the CPU of the ECU 60 turns on the system main relay SMR (S100) and waits until a time tref has elapsed (S110). The time tref is a time determined in advance by experiment, analysis, or machine learning as a sufficient time for the capacitors 46, 48 to be charged and for the voltages Vinv, Vdc detected by the voltage sensors 46a, 48a to rise to a predetermined voltage Vref (e.g., several volts) higher than 0 when no break occurs in the first and second power lines 42, 44.

[0019] When the time tref has elapsed, the ECU 60 inputs the voltages Vb, Vinv, and Vdc detected by the voltage sensors 36a, 46a, and 48a (S120). Then, it is determined whether or not the voltages Vinv and Vdc have both increased from the value 0 (S130). When the voltages Vinv and Vdc are both equal to or higher than the predetermined voltage Vref, it is determined that the voltages Vinv and Vdc have both increased from the value 0. When the voltages Vinv and Vdc have both increased from the value 0, it is determined that the first and second power lines 42 and 44 are not disconnected and are normal (S140), and this routine ends. When the ECU 60 determines that the system is normal in S140, it starts up the system, and after the system is started up, it executes the above-mentioned charging control and assist control.

[0020] When at least one of the voltages Vinv and Vdc has not increased in S130, it is determined whether the voltage Vinv is 0 (not increasing) and whether the voltages Vb and Vdc are equal (S150). When the voltage Vinv is 0 and the voltages Vb and Vdc are equal, it is determined that an abnormality has occurred on the inverter 34 side from the connection point of the first power line 42 and the second power line 44 (S160), and this routine ends. When it is determined that an abnormality has occurred on the inverter 34 side from the connection point of the first power line 42 and the second power line 44, the ECU 60 starts up the system, and after the start-up, it stops driving the motor 32 and executes motorless control to control the DC / DC converter 50 so that the low-voltage battery 54 is charged with power from the high-voltage battery 36.

[0021] If the voltage Vinv is not 0 or the voltage Vb is not equal to the voltage Vdc in S150, it is then determined whether the voltage Vdc is 0 (not rising) and the voltage Vb is equal to the voltage Vinv (S170). If the voltage Vdc is 0 and the voltage Vb is equal to the voltage Vinv, it is determined that an abnormality has occurred on the first power line 42 side of the capacitor 48 of the second power line 44, causing a disconnection (S180), and this routine is terminated. When it is determined that an abnormality has occurred on the first power line 42 side of the capacitor 48 of the second power line 44, causing a disconnection, the ECU 60 starts up the system, and after the system start-up, it stops driving the DC / DC converter 50 and executes the above-mentioned assist control.

[0022] When the voltage Vdc is not equal to 0 in S170 or when the voltage Vb is not equal to the voltage Vinv, it is then determined whether the voltage Vb exceeds the determination voltage Vbref and the voltages Vdc and Vinv are both equal to 0 (S190). The determination voltage Vbref is a threshold value for determining whether the high-voltage battery 36 is normal. When the voltage Vb exceeds the determination voltage Vbref and the voltages Vdc and Vinv are both equal to 0, it is determined that an abnormality has occurred, causing a disconnection between the connection point of the first power line 42 with the second power line 44 and the system main relay SMR (S200), and this routine is terminated. When the ECU 60 determines that an abnormality has occurred, causing a disconnection between the connection point of the first power line 42 with the second power line 44 and the system main relay SMR, the ECU 60 starts up the system, and after startup, executes batteryless control in which the system main relay SMR is turned off and power from the motor 32 is supplied to the low-voltage battery 54 via the DC / DC converter 50, thereby controlling the DC / DC converter 50 so that the low-voltage battery 54 is charged.

[0023] If, in S190, the voltage Vb is equal to or lower than the reference voltage Vbref or if the voltages Vdc and Vinv are not both 0, it is determined that the location where the disconnection abnormality has occurred cannot be identified, and this routine is terminated. By executing such a startup determination process, the location where the disconnection abnormality has occurred in the electric drive system 20 can be identified.

[0024] Next, an operation of determining whether an abnormality is due to a disconnection in the first and second power lines 42, 44 when a voltage abnormality occurs in which the voltage Vinv detected by the voltage sensor 46a exceeds the upper limit voltage Vmax after the system is started will be described. Fig. 3 is a flowchart showing an example of a voltage abnormality process executed by the ECU 60. This routine is executed when the voltage Vinv exceeds the upper limit voltage Vmax after the first and second power lines 42, 44 are determined to be normal and the system is started.

[0025] When this routine is executed, the CPU of the ECU 60 inputs the voltages Vdc, Vinv, and Vb in the same process as in S120 described above (S300). Then, it is determined whether the voltages Vdc and Vinv are equal (S310). When the voltages Vdc and Vinv are equal, it is determined that an abnormality has occurred on the system main relay SMR side from the connection point of the first power line 42 and the second power line 44, causing a disconnection (S320), and this routine ends. When the ECU 60 determines that an abnormality has occurred on the system main relay SMR side from the connection point of the first power line 42 and the second power line 44, causing a disconnection, it executes the batteryless control described above.

[0026] If it is determined in S310 that the voltages Vdc and Vinv are not equal, it is then determined whether the voltages Vdc and Vb are equal (S330). If the voltages Vdc and Vb are equal, it is determined that at least one of an abnormality occurring on the inverter 34 side of the connection point of the first power line 42 with the second power line 44, or an abnormality in the voltage sensor 46a, has occurred (S340), and this routine is terminated. If it is determined that an abnormality occurring on the inverter 34 side of the connection point of the first power line 42 with the second power line 44, or an abnormality in the voltage sensor 46a, has occurred, the motorless control described above is executed.

[0027] If voltage Vdc and voltage Vb are not equal in S330, it is determined that it is not possible to identify the location of the disconnection or to determine whether there is an abnormality in the voltage sensor, and this routine is terminated. In this case, inverter 34 is not driven, and the charge in capacitor 46 is discharged via a discharge resistor (not shown) connected between the positive line of power line 42 and ground. By executing such a process for voltage abnormality, it is possible to identify the location of the disconnection in electric drive system 20 and to determine whether there is an abnormality in the voltage sensor.

[0028] According to the electric drive system 20 provided in a vehicle equipped with the vehicle control device of the present embodiment described above, the location where the abnormality has occurred in the electric drive system 20 as a circuit including the motor 32, the inverter 34, the high-voltage battery 36, and the DC / DC converter 50 can be identified based on the voltages of at least the voltage sensors 46a, 48a, thereby making it possible to identify the location where the abnormality has occurred in the electric drive system 20.

[0029] In the above-described embodiment, in the abnormal voltage process illustrated in FIG. 3, S330 may not be executed, and S340 may be executed if it is determined in S310 that the voltage Vdc and the voltage Vinv are not equal.

[0030] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the embodiment is an example for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the Means for Solving the Problem column.

[0031] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure. [Industrial Applicability]

[0032] The present disclosure can be used in the vehicle control device manufacturing industry and the like. [Explanation of symbols]

[0033] 36a, 46a, 48a voltage sensors, 60 electronic control unit (ECU).

Claims

[Claim 1] A driving motor; an inverter that drives the motor; a battery connected to a first power line, which is a power line of the inverter, for exchanging power with the motor; a DC / DC converter connected to the first power line via a second power line and configured to convert a voltage from the battery; A vehicle control device for controlling the motor, the inverter, and the DC / DC converter, The vehicle is a first voltage sensor that detects a voltage of the first power line; a second voltage sensor for detecting a voltage of the second power line; Equipped with A location where an abnormality has occurred in a circuit including the motor, the inverter, the battery, and the DC / DC converter is identified based on at least the voltages of the first and second voltage sensors. Vehicle control device.

Images