CN112848900B

CN112848900B - Vehicle driving device

Info

Publication number: CN112848900B
Application number: CN202011306710.9A
Authority: CN
Inventors: 前田好彦; 吉川明孝
Original assignee: Panasonic Automotive Systems Co Ltd
Current assignee: Panasonic Automotive Systems Co Ltd
Priority date: 2019-11-26
Filing date: 2020-11-20
Publication date: 2024-07-05
Anticipated expiration: 2040-11-20
Also published as: CN112848900A

Abstract

Provided is a vehicle drive device capable of stably performing a three-phase short circuit. A vehicle driving device (5) is provided with: a microcontroller (40) that outputs a PWM signal that controls an inverter (10) for driving a three-phase motor, wherein a plurality of switching elements S1-S6 are connected in a three-phase bridge configuration; a PWM driving circuit (50) for driving the plurality of switching elements S1-S6 according to the PWM signal; a three-phase short-circuit driving circuit (60) performs a three-phase short circuit in which switching elements S4 to S6 of a lower arm are short-circuited together when an abnormality occurs in an inverter (10). The three-phase short-circuit driving circuit (60) has: a gate output of a PWM drive circuit (50) is cut off by a command signal of a three-phase short circuit, a power supply changeover switch (61) for applying a voltage to gates of switching elements S4 to S6 of a lower arm, and an insulation switch (63) for shorting gate sources of switching elements S1 to S3 of an upper arm.

Description

Vehicle driving device

Technical Field

The present disclosure relates to a vehicle drive device.

Background

Due to the limitation of Fuel consumption and the limitation of CO ₂, the electric motor of vehicles such as EV (ELECTRIC VEHICLE: electric vehicle), HEV (Hybrid ELECTRIC VEHICLE: hybrid vehicle), PHV (Plug-in Hybrid Vehicle: plug-in Hybrid vehicle), FCV (Fuel CELL VEHICLE: fuel cell vehicle) and the like have been developed. In addition, in order to improve the electric efficiency of the vehicle, there are many vehicles using a permanent magnet motor as a motor for driving the vehicle.

The permanent magnet motor is efficient because no exciting current is required, but the induced voltage generated by the exciting flux of the permanent magnet rises in proportion to the rotation speed, and when the rotation speed becomes equal to or higher than a predetermined rotation speed, the induced voltage exceeds the output voltage of the inverter. Therefore, when the permanent magnet motor is rotated at a high speed, the weak magnetic flux control is performed in order to suppress an induced voltage generated by the exciting magnetic flux of the permanent magnet.

On the other hand, when an abnormality occurs in the inverter during high-speed rotation, for example, when a contact failure occurs in a terminal of a battery for high voltage, and power supply for weak magnetic flux control is interrupted, a switching element of the inverter may be damaged due to a large induced voltage generated by rotation of the permanent magnet motor.

As a countermeasure, three phases of the permanent magnet motor are set as short-circuit states, and three-phase short-circuit control is performed so that the voltage induced from the permanent magnet motor becomes almost 0 (zero). As an example of such three-phase short-circuit control, patent document 1 describes a vehicle driving device including: an inverter for driving the permanent magnet motor; an abnormality detection unit that detects an abnormality such as an overvoltage generated in the inverter; and a three-phase short circuit for bringing the inverter into a three-phase short circuit control state by a logic circuit (logic IC). In this vehicle driving device, when the abnormality detection unit detects an abnormality, the inverter is switched from a state of three-phase PWM (Pulse Width Modulation: pulse width modulation) control to a state of three-phase short circuit control, whereby the overvoltage applied to the inverter is reduced.

(Prior art literature)

(Patent literature)

Patent document 1: japanese patent laid-open No. 2015-198503

However, in the vehicle driving device described in patent document 1, the inverter is switched to a three-phase short-circuit control state by a logic circuit, in other words, the gate is directly driven by the logic circuit. A logic circuit generally has difficulty outputting electric power for maintaining a gate potential. In other words, in the vehicle driving device described in patent document 1, a three-phase short circuit may not be stably implemented.

Disclosure of Invention

Accordingly, the present disclosure relates to a vehicle driving device capable of stably implementing a three-phase short circuit.

A vehicle driving device according to an aspect of the present disclosure includes: a microcontroller that outputs a PWM signal that is a pulse width modulation signal for controlling an inverter for driving a three-phase motor mounted on a vehicle, the inverter having a plurality of switching elements connected in a three-phase bridge configuration; a PWM driving circuit that drives the plurality of switching elements according to the PWM signal output from the microcontroller; and a three-phase short-circuit driving circuit that performs a three-phase short circuit when the inverter is abnormal, the three-phase short circuit being that switching elements of a lower arm among the plurality of switching elements are short-circuited together, the three-phase short-circuit driving circuit having a1 st switch and a 2 nd switch, the 1 st switch cutting off a gate output of the PWM driving circuit by a command signal of the three-phase short circuit and applying a voltage to the gate of the switching element of the lower arm, the 2 nd switch short-circuiting between gate sources of switching elements of an upper arm among the plurality of switching elements by the command signal of the three-phase short circuit.

A vehicle driving device according to an aspect of the present disclosure can stably implement a three-phase short circuit in an inverter.

Drawings

Fig. 1 is a schematic diagram illustrating an electric vehicle including a vehicle driving device according to embodiment 1.

Fig. 2 is a circuit diagram illustrating an example of a three-phase bridge circuit provided in an inverter of the vehicle driving device according to embodiment 1.

Fig. 3A is a block diagram showing a functional configuration of one phase in the inverter according to embodiment 1.

Fig. 3B is a block diagram showing an example of a step-down DC power supply of the vehicle driving device according to embodiment 1.

Fig. 4 is a flowchart showing an example of the operation of the vehicle driving device according to embodiment 1.

Fig. 5 is a block diagram showing a functional configuration of one phase in an inverter according to a modification of embodiment 1.

Fig. 6 is a block diagram showing a functional configuration of an abnormality detection circuit according to a modification of embodiment 1.

Fig. 7 is a flowchart showing an example of the operation of the vehicle driving device according to the modification of embodiment 1.

Fig. 8 is a block diagram showing a functional configuration of one phase in the inverter according to embodiment 2.

Fig. 9 is a flowchart showing an example of the operation of the vehicle driving device according to embodiment 2.

Fig. 10 is a circuit diagram illustrating an example of a three-phase bridge circuit provided in an inverter of a vehicle driving device according to embodiment 3.

Fig. 11A is a block diagram showing a functional configuration of one phase in the inverter according to embodiment 3.

Fig. 11B is a block diagram showing an example of a step-down DC power supply of the vehicle driving device according to embodiment 3.

Fig. 12 is a flowchart showing an example of the 1 st operation of the vehicle driving device according to embodiment 3.

Fig. 13 is a flowchart showing an example of the 2 nd operation of the vehicle driving device according to embodiment 3.

Fig. 14 is a block diagram showing a functional configuration of one phase in an inverter according to a modification of embodiment 3.

Fig. 15 is a block diagram showing a functional configuration of an abnormality detection circuit according to a modification of embodiment 3.

Fig. 16 is a flowchart showing an example of the operation of the vehicle driving device according to the modification of embodiment 3.

Fig. 17 is a block diagram showing a functional configuration of one phase in the inverter according to embodiment 4.

Fig. 18 is a flowchart showing an example of the operation of the vehicle driving device according to embodiment 4.

Fig. 19 is a block diagram showing a functional configuration of one phase in the inverter according to embodiment 5.

Fig. 20 is a block diagram showing a functional configuration of one phase in the inverter according to embodiment 6.

Detailed Description

A vehicle driving device according to an aspect of the present disclosure includes: a microcontroller that outputs a PWM signal that is a pulse width modulation signal for controlling an inverter for driving a three-phase motor mounted on a vehicle, the inverter having a plurality of switching elements connected in a three-phase bridge configuration; a PWM driving circuit that drives the plurality of switching elements according to the PWM signal output from the microcontroller; and a three-phase short-circuit driving circuit that performs a three-phase short circuit when the inverter is abnormal, the three-phase short circuit being a short circuit of switching elements of a lower arm among the plurality of switching elements together. The three-phase short-circuit driving circuit has a1 st switch and a2 nd switch, wherein the 1 st switch cuts off a gate output of the PWM driving circuit and applies a voltage to the gate of the switching element of the lower arm by the command signal of the three-phase short circuit, and the 2 nd switch short-circuits between gate and source electrodes of the switching element of the upper arm among the plurality of switching elements by the command signal of the three-phase short circuit.

Accordingly, in the vehicle driving device, when the inverter is in the three-phase short-circuit control state by the command signal of the three-phase short circuit, the 1 st switch applies a voltage to the gate of the switching element of the lower arm, so that the switching element can be turned on. In the vehicle driving device, when the inverter is in the three-phase short-circuit control state by the command signal of the three-phase short circuit, the gate-source of the switching element of the upper arm is short-circuited by the 2 nd switch, and the switching element can be forcibly turned off. Thus, the vehicle driving device can stably perform the three-phase short circuit.

Further, for example, the power supply of the PWM driving circuit may be a power supply based on at least one of a1 st dc battery and a2 nd dc battery, wherein the 1 st dc battery is a battery for driving the three-phase motor, and the 2 nd dc battery is a battery for supplying electric power to an electric component of the vehicle, and a voltage of the battery is lower than that of the 1 st dc battery.

Thus, the vehicle driving device can apply a voltage to the gate of the switching element of the lower arm with a simple configuration in which the power supply for the PWM driving circuit and the gate of the switching element of the lower arm are connected via the 1 st switch without providing a dedicated power supply.

Furthermore, for example, the abnormality of the inverter may include an abnormality of the microcontroller.

Accordingly, when the microcontroller is abnormal and the microcontroller cannot normally control the on/off of the switching element, the vehicle driving device is in a state of three-phase short-circuit control. The vehicle driving device is in a state of three-phase short-circuit control when it is difficult to suppress an increase in the induced voltage, for example, because the weak magnetic flux control cannot be performed due to an abnormality of the microcontroller. Thus, the vehicle driving device can suppress an increase in the induced voltage due to the occurrence of an abnormality in the microcontroller.

Further, for example, the vehicle driving device may further include an abnormality detection circuit for detecting an abnormality of the microcontroller, and the abnormality detection circuit may be configured to output the command signal for the three-phase short circuit to the three-phase short circuit driving circuit when detecting the abnormality of the microcontroller.

Accordingly, the vehicle driving device is in a state of three-phase short-circuit control when the microcontroller is abnormal, and therefore, it is possible to suppress an increase in the induced voltage due to the occurrence of the abnormality of the microcontroller.

Further, for example, the abnormality of the inverter may include an overvoltage state in which the voltage of the 1 st dc battery exceeds a predetermined voltage.

Accordingly, the vehicle driving device is in a state of three-phase short-circuit control when an overvoltage is generated in the inverter, and therefore, the overvoltage applied to the three-phase bridge circuit can be reduced.

The vehicle driving device may further include an overvoltage detection circuit for detecting the overvoltage state, wherein the overvoltage detection circuit is electrically connected to the 1 st dc battery connected to the inverter, and outputs the command signal for the three-phase short circuit to the three-phase short circuit driving circuit when the overvoltage state is detected.

Thus, the overvoltage detection circuit electrically connected to the 1 st dc battery can detect the overvoltage of the inverter.

Further, for example, the vehicle driving device may further include a latch circuit that holds the command signal of the three-phase short circuit, and an output of the latch circuit may be input to the 1 st switch and the 2 nd switch.

Accordingly, when the voltage value of the overvoltage of the inverter fluctuates before and after the threshold value of the overvoltage is determined, the state of the normal control and the state of the three-phase short-circuit control can be suppressed from being repeatedly switched in a short period of time. In other words, the vehicle driving device can more stably perform the three-phase short circuit. Further, by using the latch circuit, switching of the 1 st switch and the 2 nd switch can be performed simultaneously.

Further, for example, the vehicle driving device may further include a semiconductor switch connected to the 2 nd switch and the switching element of the upper arm, wherein the 2 nd switch is a photoelectric coupling element, the command signal short-circuited by the three phases is input to the photoelectric coupling element, and the semiconductor switch is turned on to short-circuit between the gate and the source of the switching element of the upper arm.

Accordingly, the 2 nd switch can discharge the charge stored in the gate while maintaining insulation between the semiconductor switch and a member (for example, a latch circuit) connected to the 2 nd switch. In addition, the operation of the 2 nd switch can be performed at high speed.

Further, for example, the 2 nd switch may have a relay, and the command signal is input by the three-phase short circuit, and the relay may be turned on to short-circuit between the gate and the source of the switching element of the upper arm.

Accordingly, the 2 nd switch can discharge the charge stored in the gate while maintaining insulation between the gate of the switching element of the upper arm and a member (for example, a latch circuit) connected to the 2 nd switch. In addition, the 2 nd switch can be realized with a simple configuration.

For example, the vehicle driving device may further include a three-phase short-circuit switching circuit that outputs a signal for performing a three-phase short-circuit to the PWM driving circuit when the inverter is abnormal, wherein the three-phase short-circuit is a short-circuit of all switching elements of a lower arm among the plurality of switching elements, the three-phase short-circuit switching circuit is electrically connected between the microcontroller and the PWM driving circuit, outputs the PWM signal to the PWM driving circuit as a driving signal in a normal operation, and outputs the driving signal for turning on the switching element of the lower arm and turning off the switching element of an upper arm among the plurality of switching elements to the PWM driving circuit when a command signal for the three-phase short-circuit is input.

Thus, even when the 1 st switch fails and the connection cannot be switched to the three-phase short-circuit driving, the vehicle driving device performs the three-phase short-circuit driving by the driving signal from the three-phase short-circuit switching circuit. Thus, the reliability of being able to perform three-phase short-circuit driving is increased.

Further, for example, the three-phase short-circuit switching circuit may include a logic circuit that outputs the driving signal to the PWM driving circuit.

Thus, the vehicle driving device can perform the on/off operation of the plurality of switching elements at a higher speed than the case where the logic circuit is not used.

Further, for example, the vehicle driving device may further include an abnormality detection circuit for detecting an abnormality of the microcontroller, and the abnormality detection circuit may output the command signal for the three-phase short circuit to the three-phase short circuit switching circuit when detecting an abnormality of the microcontroller.

Further, for example, the abnormality of the inverter may include an overvoltage state in which a voltage of a power supply for driving the three-phase motor exceeds a predetermined voltage.

The vehicle driving device may further include an overvoltage detection circuit for detecting the overvoltage state, the overvoltage detection circuit may be electrically connected to the power supply connected to the inverter, and the command signal for the three-phase short circuit may be output to the three-phase short circuit switching circuit when the overvoltage state is detected.

Further, for example, the three-phase short-circuit switching circuit may further include a latch circuit that holds the command signal of the three-phase short circuit.

Accordingly, when the voltage value of the overvoltage of the inverter fluctuates before and after the threshold value of the overvoltage is determined, the state of the normal control and the state of the three-phase short-circuit control can be suppressed from being repeatedly switched in a short period of time. In other words, the vehicle driving device can more stably perform the three-phase short circuit.

For example, the drive signal may include an upper arm drive signal that drives a switching element of an upper arm of the plurality of switching elements and a lower arm drive signal that drives a switching element of a lower arm, and the three-phase short-circuit switching circuit may further include a monitor circuit to which the upper arm drive signal and the lower arm drive signal are input, and the monitor circuit may cause a shut-off circuit to perform an operation that shuts off an output of the PWM drive circuit to the plurality of switching elements when detecting that the upper arm drive signal and the lower arm drive signal are signals that turn on the switching element of the upper arm and the switching element of the lower arm at the same time.

Accordingly, when a component, a board, or the like included in the three-phase short-circuit switching circuit fails and a signal for simultaneously turning on the switching elements of the upper and lower arms is output, the drive signals from the PWM drive circuit to the plurality of switching elements are cut off. In other words, each of the plurality of switching elements becomes off. Thus, the vehicle driving device can suppress the occurrence of an up-down short circuit by simultaneously turning on the switching elements of the upper and lower arms.

Further, for example, the monitoring circuit may output a detection result to the microcontroller, and the microcontroller may prohibit the output of the command signal for the three-phase short circuit and output a signal for limiting the rotation speed of the three-phase motor when the detection result is obtained.

Thus, the vehicle driving device can prohibit the three-phase short-circuit driving when the three-phase short-circuit switching circuit is abnormal. In addition, the vehicle driving device outputs a signal for limiting the rotation speed of the three-phase motor to the upper-level ECU (Electronic Control Unit), for example, and the upper-level ECU controls the speed of the vehicle to be low, so that the inverter can be kept in an overvoltage state by suppressing the increase in the rotation speed of the three-phase motor.

For example, when it is detected that the upper arm drive signal and the lower arm drive signal are signals for turning on the switching elements of the upper arm and the switching elements of the lower arm simultaneously, the shut-off circuit may shut off the outputs from the PWM drive circuit to the plurality of switching elements.

Accordingly, when it is detected that the upper arm drive signal and the lower arm drive signal are both on, the signal output from the PWM drive circuit to the plurality of switching elements is cut off by the cut-off circuit, and the signal is cut off on the path. In other words, the driving signals from the PWM driving circuit to the plurality of switching elements are not input to the plurality of switching elements. Accordingly, in the vehicle driving device, when a failure occurs in a component, a board, or the like included in the three-phase short-circuit switching circuit, and a signal for simultaneously turning on the switching elements of the upper and lower arms is output, the switching elements of the upper and lower arms are simultaneously turned off, and occurrence of an up-down short circuit can be suppressed.

For example, when it is detected that the upper arm drive signal and the lower arm drive signal are signals for turning on the switching element of the upper arm and the switching element of the lower arm simultaneously, the cut-off circuit may cut off the power supply to the PWM drive circuit.

Accordingly, when it is detected that the upper arm drive signal and the lower arm drive signal are both on, the power supply to the PWM drive circuit is turned off by the cut-off circuit. In other words, the output of the driving signals from the PWM driving circuit to the plurality of switching elements is stopped. Accordingly, in the vehicle driving device, when a failure occurs in a component, a board, or the like included in the three-phase short-circuit switching circuit, and a signal for simultaneously turning on the switching elements of the upper and lower arms is output, the switching elements of the upper and lower arms are simultaneously turned off, and occurrence of an up-down short circuit can be suppressed.

Further, for example, the shutdown circuit may be electrically connected between the 1 st switch and the PWM driving circuit.

Accordingly, when the logic circuit fails and outputs a signal that is turned on at the same time, the PWM driving circuit can be turned off by the cutoff circuit.

In addition, these general and specific aspects may be implemented by a system, method, or integrated circuit, or any combination of systems, methods, or integrated circuits.

Hereinafter, embodiments will be described specifically with reference to the drawings.

In addition, the embodiments to be described below are one general or specific example. The numerical values, shapes, materials, components, arrangement positions of components, connection patterns, steps, order of steps, and the like shown in the following embodiments are examples, and the gist of the present invention is not limited thereto. The following embodiments will be described with reference to the accompanying drawings, which are not intended to limit the scope of the invention. The drawings are schematic drawings, and are not strict. In the drawings, the same constituent members are given the same reference numerals.

In the present specification, terms and numerical values indicating the relationship between elements such as the same time are not strictly expressed, but represent substantially equivalent ranges, for example, expression including a difference of about several%.

(Embodiment 1)

Hereinafter, a vehicle driving device according to the present embodiment will be described with reference to fig. 1 to 4.

[1-1. Construction of vehicle drive device ]

First, the configuration of the vehicle driving device 5 according to the present embodiment will be described with reference to fig. 1 to 3B. Fig. 1 is a diagram illustrating an electric vehicle 1 provided with a vehicle driving device 5 according to the present embodiment.

As shown in fig. 1, the electric vehicle 1 includes a drive wheel 2, a power transmission mechanism 3, a permanent magnet motor M1, an inverter 10, and a battery P1. In these configurations, the vehicle driving device 5 is configured by the permanent magnet motor M1, the inverter 10, and the battery P1. Hereinafter, the permanent magnet motor M1 is sometimes referred to as a motor M1. The electric vehicle 1 is an example of a vehicle.

The motor M1 is a three-phase ac motor (three-phase motor) for driving the drive wheels 2 of the electric vehicle 1, and is, for example, an embedded magnet type synchronous motor or a surface magnet type synchronous motor.

The power transmission mechanism 3 is constituted by, for example, a differential gear and a drive shaft, and transmits power between the motor M1 and the drive wheels 2. The rotational force of the motor M1 is transmitted to the driving wheel 2 via the power transmission mechanism 3. Likewise, the rotational force of the driving wheel 2 is transmitted to the motor M1 via the power transmission mechanism 3. The electric vehicle 1 may not include the power transmission mechanism 3, and the motor M1 and the drive wheels 2 may be directly coupled.

The battery P1 is a dc power supply such as a lithium ion battery. The battery P1 supplies electric power for driving the motor M1, and accumulates the electric power. The battery P1 is an example of the 1 st dc battery. The voltage of the battery P1 is, for example, 48V, but is not limited thereto. The battery P1 may be a higher voltage than a low-voltage dc battery described later, and may be referred to as a high-voltage dc battery.

The inverter 10 converts the direct current supplied from the battery P1 into, for example, three-phase alternating current, and supplies the alternating current to the motor M1. In this way, the vehicle driving device 5 is configured to drive the three-phase ac motor M1 by the electric power of the battery P1. The inverter 10 is, for example, a plurality of switching elements S1 to S6 connected in a three-phase bridge configuration.

Fig. 2 is a circuit diagram illustrating an example of a three-phase bridge circuit 20 provided in the inverter 10 of the vehicle driving device 5 according to the present embodiment. In addition, the voltage Vp shown in fig. 2 is a power supply voltage, and the voltage Vg is a ground voltage.

As shown in fig. 2, the vehicle driving device 5 includes a motor M1, an inverter 10, and a battery P1. The inverter 10 includes a three-phase bridge circuit 20 and a control circuit 30. In addition, fig. 2 also shows a smoothing capacitor C1 that smoothes the voltage applied to the three-phase bridge circuit 20.

The three-phase bridge circuit 20 is a circuit that converts direct current supplied from the battery P1 into three-phase alternating current by switching operation, supplies the three-phase alternating current to the motor M1, and drives the motor M1. The input side for controlling the switching operation of the three-phase bridge circuit 20 is connected to the PWM driving circuit 50 and the three-phase short-circuit driving circuit 60, the input side of the electric power is connected to the battery P1, and the output side is connected to the motor M1.

In addition, during the regeneration of the motor M1, a regenerative current is introduced from the output side of the three-phase bridge circuit 20 and flows to the input side of the electric power, and the side connected to the battery P1 is defined as the input side and the side connected to the motor M1 is defined as the output side.

The three-phase bridge circuit 20 is formed by connecting a plurality of switching elements S1 to S6 in a three-phase bridge structure. The three-phase bridge circuit 20 has: switching elements S1, S2, and S3 provided in an upper arm group located above the paper surface of fig. 2; and switching elements S4, S5, and S6 provided in a lower arm group located below the paper surface of fig. 2. For example, the switching elements S1 to S6 are formed of Field Effect Transistors (FETs), insulated Gate Bipolar Transistors (IGBTs), or the like. The switching elements S1 to S6 may be formed using a wide band gap semiconductor.

Each of the switching elements S1, S2, S3 is connected between 3 output lines led out from three terminals of the motor M1 and a power supply line Lp connected to the positive electrode of the battery P1. The switching elements S4, S5, and S6 are connected between the 3 output lines and the ground line Lg, and the ground line Lg is connected to the negative electrode of the battery P1. The flywheel diodes are connected in parallel to the switching elements S1 to S6. The flywheel diode may be a parasitic diode parasitic to each of the switching elements S1 to S6. In the following, the switching elements S1, S2, and S3 provided in the upper arm group may be referred to as switching elements S1, S2, and S3 of the upper arm, and the switching elements S4, S5, and S6 provided in the lower arm group may be referred to as switching elements S4, S5, and S6 of the lower arm.

The switching elements S1 to S6 are connected to the control circuit 30, and are driven by signals output from the control circuit 30. Specifically, the switching elements S1 to S6 convert the dc power supplied from the battery P1 into three-phase ac power by switching operation based on the signal output from the PWM driving circuit 50, and supply the ac power to the motor M1. The motor M1 is driven in a state of traction, regeneration, coasting, or the like according to the driving of the switching elements S1 to S6. The switching elements S1 to S6 are in a three-phase short-circuited state in which the switching elements S1, S2, S3 of the upper arm are turned off together and the switching elements S4, S5, S6 of the lower arm are short-circuited together, based on the signal output from the three-phase short-circuit driving circuit 60.

The control circuit 30 is a control device for controlling the driving of the switching elements S1 to S6. The control circuit 30 includes a microcontroller 40, a PWM drive circuit 50, and a three-phase short circuit drive circuit 60. Hereinafter, the microcontroller 40 is also referred to as a microcontroller 40.

The microcontroller 40 controls the inverter 10, the inverter 10 being for driving the motor M1 mounted on the electric vehicle 1, the inverter 10 including a three-phase bridge circuit 20 having a plurality of switching elements S1 to S6. The microcontroller 40 is electrically connected to the PWM driving circuit 50 and the three-phase short-circuit driving circuit 60, and generates and outputs control signals for controlling the PWM driving circuit 50 and the three-phase short-circuit driving circuit 60, respectively. The microcontroller 40 is configured by a microprocessor that performs various operations and the like, a memory that stores programs, information, and the like for operating the microprocessor, and peripheral circuits.

The microcontroller 40 obtains information detected by various sensors including a current sensor CSu, CSv, CSw that detects a current flowing into the motor M1, a rotational position sensor RS that detects a magnetic pole position of the motor M1 and detects a rotational position, and the like. The current sensor CSu, CSv, CSw is a sensor for detecting current values of u-phase, v-phase, and w-phase of the motor M1. In addition, the microcontroller 40 obtains information about the voltage Vp in the power supply line Lp. The microcontroller 40 obtains control instruction information such as a torque instruction or a drive regeneration instruction signal, which is output from the outside of the control circuit 30, for example, from an ECU (Electronic Control Unit: electronic control unit) of the electric vehicle 1. The microcontroller 40 obtains the respective pieces of information, for example, via a motor control signal obtaining unit (not shown).

Based on the obtained information, the microcontroller 40 converts the torque command value into a current by calculation, and outputs a control signal for controlling the current of the motor M1. For example, the microcontroller 40 calculates a drive signal (for example, a PWM signal described later) necessary for driving the motor M1 so that the torque of the motor M1 at the time of driving the vehicle driving device 5 becomes a target torque (for example, a torque corresponding to an operation amount of an accelerator pedal or a brake pedal of the electric vehicle 1) indicated by torque command information, and outputs the drive signal to the PWM driving circuit 50. The microcontroller 40 outputs a drive signal for performing three-phase PWM control when the vehicle drive device 5 is normally driven. The drive signal is a control signal for current control of the motor M1.

The microcontroller 40 is an example of a signal generating unit that generates a drive signal. The signal generating unit is not limited to the microcontroller 40, and may be a microprocessor, a CPU (central processing unit), or the like.

The PWM driving circuit 50 controls driving of the plurality of switching elements S1 to S6 based on a PWM signal (an example of a driving signal) output from the microcontroller 40. The PWM driving circuit 50 converts the dc power supplied from the battery P1 into three-phase ac power, and controls the switching operation of each of the switching elements S1 to S6 so as to supply the ac power to the motor M1.

In order to suppress overvoltage applied to the inverter 10 when the inverter 10 is abnormal, the three-phase short-circuit driving circuit 60 performs a three-phase short-circuit in which the switching elements S4, S5, and S6 of the lower arm are short-circuited together among the plurality of switching elements S1 to S6. Specifically, the three-phase short-circuit driving circuit 60 turns off the switching elements S1, S2, S3 (switching elements of the upper arm) and turns on the switching elements S4, S5, S6 (switching elements of the lower arm) when the inverter 10 is abnormal.

Accordingly, the induced voltage generated from the motor M1 becomes almost 0 (zero), so that the overvoltage of the three-phase bridge circuit 20 can be suppressed. In addition, for example, overvoltage may occur due to disconnection of the positive-side wiring of the battery P1, disconnection of a wire, disconnection of a main relay, not shown, provided in the battery P1, or the like.

In the present embodiment, the abnormality of the inverter 10 is described as an example of an overvoltage state in which an overvoltage is generated in the inverter 10, in other words, the voltage of the battery P1 exceeds a predetermined voltage, but the present invention is not limited to this.

Details of the configuration and the like of the three-phase short-circuit driving circuit 60 will be described with reference to fig. 3A and 3B. Fig. 3A is a block diagram showing a functional configuration of one phase in the inverter 10 according to the present embodiment. Fig. 3B is a block diagram illustrating one embodiment of a buck DC power supply 70. Fig. 3A shows a functional configuration of the u-phase in the inverter 10. The u-phase is described below, but v-phase and w-phase are the same.

As shown in fig. 3A, the inverter 10 has a step-down DC power supply 70 and an overvoltage detection circuit 80 in addition to the control circuit 30. The three-phase short-circuit driving circuit 60 includes a power supply changeover switch 61, a latch circuit 62, an insulating switch 63, a discharge circuit 64, and resistor elements R1 to R3.

The step-down DC power supply 70 is a power supply for driving the PWM driving circuit 50. The step-down DC power supply 70 supplies a voltage of about 12V to 15V to the PWM driving circuit 50, for example. In the present embodiment, the step-down DC power supply 70 further supplies a voltage for turning on the switching element S4 of the lower arm when the three-phase short-circuit driving is performed, to the gate of the switching element S4. The step-down DC power supply 70 supplies no voltage to the gate of the switching element S4 via the PWM driving circuit 50 by switching the power supply changeover switch 61 when three-phase short-circuit driving is performed. The step-down DC power supply 70 is an example of a power supply of the PWM driving circuit 50.

The step-down DC power supply 70 is a power supply based on at least one of a battery P1 for driving the motor M1 and a low-voltage direct-current battery lower in voltage than the battery P1 for supplying electric power to electric components of the electric vehicle 1. As shown in fig. 3A, the step-down DC power supply 70 is a power supply that steps down the voltage of the battery P1 by a DC/DC converter. The step-down DC power supply 70 may be a low-voltage direct-current battery, that is, a battery P2 (see fig. 3B). In this case, the low-voltage direct-current battery is, for example, a 12V storage battery. The low-voltage dc battery is an example of the 2 nd dc battery.

In the case where the step-down DC power supply 70 is a power supply based on both the battery P1 and the battery P2 of the low-voltage direct-current battery, as shown in fig. 3B, the output of the DC/DC converter 71 that steps down the voltage of the battery P1 may be connected to the battery P2 via a diode OR to the power supply switching switch 61. For example, power is supplied from a battery on the side of a diode having a high voltage via the power supply changeover switch 61.

The overvoltage detection circuit 80 is a circuit for detecting a predetermined overvoltage of the dc voltage in the three-phase bridge circuit 20. The overvoltage detection circuit 80 detects, for example, a predetermined overvoltage in the power supply line Lp. More specifically, the overvoltage detection circuit 80 outputs a three-phase short-circuit signal for performing a three-phase short-circuit when a predetermined overvoltage in the power supply line Lp is detected. The three-phase short-circuit signal can be said to be a signal showing that an overvoltage is detected. The overvoltage detection circuit 80 is electrically connected to the power supply line Lp and the ground line Lg, respectively.

The predetermined overvoltage is a voltage predetermined as a voltage that does not exceed the tolerable voltage of the components constituting the circuit. The components constituting the circuit are, for example, switching elements S1 to S6 of the three-phase bridge circuit 20, a smoothing capacitor C1, and the like. The overvoltage detection circuit 80 outputs a three-phase short-circuit signal to the three-phase short-circuit driving circuit 60. In addition, the overvoltage detection circuit 80 may output a three-phase short-circuit signal to the microcontroller 40. The three-phase short-circuit signal is, for example, a pulse signal of a high level, but is not limited thereto. The three-phase short-circuit signal is an example of a command signal for three-phase short-circuit.

The circuit configuration of the overvoltage detection circuit 80 is not particularly limited as long as it can detect an overvoltage and can output a signal indicating that the overvoltage is detected. The overvoltage detection circuit 80 includes, for example, a plurality of resistor elements and a comparator circuit. The comparison circuit includes: a +input terminal, -an input terminal, and an output terminal outputting a result of comparing the voltage of the +input terminal with the voltage of the-input terminal. The comparison circuit outputs a three-phase short-circuit signal from the output terminal, for example, when the detection voltage input to the +input terminal is higher than the reference voltage input to the-input terminal. The detection voltage is a voltage to be a target for determining whether or not the overvoltage is present, and is, for example, a voltage based on the voltage Vp on the power supply line Lp. The reference voltage is a voltage that becomes a reference for detecting an overvoltage, for example, a voltage based on a voltage (for example, 5V) in a constant voltage source. In addition, a plurality of resistance elements are used to divide the voltage Vp and the voltage in the constant voltage source.

The power supply changeover switch 61 is a switch that cuts off the gate output of the PWM driving circuit 50 by a signal from the latch circuit 62 and applies a voltage to the gate of the switching element S4 of the lower arm of the plurality of switching elements S1 to S6. In the power supply changeover switch 61, one end is connected to the step-down DC power supply 70, and one end is connected to the PWM driving circuit 50, while the other end is connected to the gate of the switching element S4, so that the power supply destination of the step-down DC power supply 70 can be selectively changed. The power supply changeover switch 61 connects the step-down DC power supply 70 to the PWM driving circuit 50 when the vehicle driving device 5 is normally driven. The power supply changeover switch 61 connects the step-down DC power supply 70 to the gate of the switching element S4 when the vehicle driving device 5 performs three-phase short-circuit driving. Note that the gate output is cut off means that, for example, the output side of the PWM driving circuit 50 is high-impedance, which will be described in detail later. The power supply changeover switch 61 is an example of the 1 st switch.

In the latch circuit 62, an input side is connected to the microcontroller 40 and the overvoltage detection circuit 80, an output side is connected to the power supply changeover switch 61 and the insulation switch 63, and a three-phase short-circuit signal output from the overvoltage detection circuit 80 is held and output to the power supply changeover switch 61 and the insulation switch 63. In other words, the output of the latch circuit 62 is input to the power supply changeover switch 61 and the insulating switch 63. In addition, in the case where the microcontroller 40 has a function of outputting a three-phase short-circuit signal, the latch circuit 62 can hold the three-phase short-circuit signal output from the microcontroller 40 and output the three-phase short-circuit signal to the power supply changeover switch 61 and the isolation switch 63.

The latch circuit 62 switches the power supply changeover switch 61 by outputting a three-phase short-circuit signal to the power supply changeover switch 61 so that the step-down DC power supply 70 is turned on with the gate of the switching element S4. The latch circuit 62 outputs a three-phase short-circuit signal to the insulating switch 63, thereby switching the insulating switch 63 from off to on. The latch circuit 62 performs, for example, switching of the power supply changeover switch 61 and switching of the insulation switch 63 at the same time.

When the three-phase short-circuit signal is obtained from the overvoltage detection circuit 80, the latch circuit 62 outputs the three-phase short-circuit signal to the power supply changeover switch 61 and the insulating switch 63 until the unlock signal is obtained from the microcontroller 40.

The insulating switch 63 short-circuits the gate and source of the switching element S1 of the upper arm among the switching elements S1 and S4 by the three-phase short-circuit signal from the latch circuit 62, and forcibly turns off the gate of the switching element S1 of the upper arm.

In the insulating switch 63, an input side is connected to the latch circuit 62, and an output side is connected to the discharge circuit 64, and is turned on when a three-phase short-circuit signal is obtained from the latch circuit 62. The insulating switch 63 is turned on, and a signal for causing the discharge circuit 64 to perform discharge is output. In the case where the discharge circuit 64 is a semiconductor switch, the output side of the insulating switch 63 is connected to the gate of the semiconductor switch, and the semiconductor switch is turned on by the insulating switch 63 being turned on.

The insulating switch 63 has a structure in which the latch circuit 62 is insulated from the discharge circuit 64, and the discharge circuit 64 can be controlled by an output from the latch circuit 62. The insulating switch 63 is realized, for example, by a photo-coupling element or a relay. Thus, the insulating switch 63 can insulate (protect) the latch circuit 62 from the discharge circuit 64.

When the insulating switch 63 is a photoelectric coupling element, the input side is connected to the latch circuit 62, and the output side is connected to the discharge circuit 64 (the gate of the semiconductor switch when the discharge circuit 64 is a semiconductor switch). In the case where the insulating switch 63 is a relay, the relay includes, for example, a switch and a coil that turns the switch on or off by a magnetic force generated by a current flow, the coil (primary winding side) is connected to the latch circuit 62, and the switch (contact side) is connected to the discharge circuit 64 (gate of the semiconductor switch in the case where the discharge circuit 64 is a semiconductor switch). The insulating switch 63 is an example of the 2 nd switch.

In the discharging circuit 64, one end (for example, a drain) is connected to the gate of the switching element S1, and the other end (for example, a source) is connected to the source of the switching element S1, and when three-phase short-circuit driving is performed, the insulating switch 63 is turned on to discharge the electric charge on the gate of the switching element S1. The discharge circuit 64 is implemented by a semiconductor switch such as a transistor. By supplying a signal from the insulating switch 63 to the gate, the gate is turned on, and the charge of the gate of the switching element S1 is discharged.

Accordingly, the discharge circuit 64 can set the gate and the source of the switching element S1 to the same potential, and thus can turn off the switching element S1. The discharge circuit 64 is provided to reliably turn off the switching element S1 when the three-phase short-circuit driving is performed.

When the insulating switch 63 is a photocoupling element, the discharge circuit 64 is input to the photocoupling element by a three-phase short-circuit signal from the latch circuit 62, and an output corresponding to the input is input to the gate of the transistor, so that the discharge circuit 64 is turned on. And the discharge circuit 64 is turned on, so that the gate and the source are short-circuited. In other words, the insulating switch 63 is input with a three-phase short-circuit signal from the latch circuit 62 to the photoelectric coupling element, and the discharge circuit 64 is turned on, thereby short-circuiting between the gate and the source of the switching element S1 of the upper arm. So that the charge of the gate of the switching element S1 is discharged.

When the insulating switch 63 is a relay, the discharge circuit 64 inputs a three-phase short-circuit signal from the latch circuit 62 to a coil of the relay, and causes a current to flow in the coil, so that a magnetic force generated by the current turns on the switch. Further, the switch is turned on, and the gate and the source are short-circuited. In other words, the insulating switch 63 is turned on by the three-phase short-circuit signal from the latch circuit 62 being input to the relay, thereby short-circuiting between the gate and the source of the switching element S1 of the upper arm. Thereby, the charge of the gate of the switching element S1 is discharged.

In addition, when the insulating switch 63 is a relay, the insulating switch 63 functions as a discharge circuit 64. In other words, the insulating switch 63 and the discharge circuit 64 can be realized by 1 circuit part.

In this way, the three-phase short-circuit driving circuit 60 has a configuration in which the switching element S1 of the upper arm is turned off and the switching element S4 of the lower arm is turned on by the three-phase short-circuit signal output from the latch circuit 62.

As shown in fig. 3A, the power supply changeover switch 61 is connected to the gate of the switching element S4 via the resistor element R1. The PWM driving circuit 50 is connected to the gate of the switching element S1 via the resistor element R2, and is connected to the gate of the switching element S4 via the resistor element R3. In other words, in the resistor element R1, one terminal is connected to the other terminal of the other end of the power supply changeover switch 61, and the other terminal is connected to the gate of the switching element S4. In the resistor element R2, one terminal is connected to the PWM driving circuit 50 (for example, a high-side terminal of the PWM driving circuit 50), and the other terminal is connected to the gate of the switching element S1. In the resistor element R3, one terminal is connected to the PWM driving circuit 50 (for example, a low side terminal of the PWM driving circuit 50), and the other terminal is connected to the gate of the switching element S4.

As described above, the three-phase short-circuit driving circuit 60 is a circuit that turns off the switching elements S1, S2, S3 of the upper arm of the three-phase bridge circuit 20 via the insulating switch 63 and turns off the switching elements S4, S5, S6 of the lower arm via the power supply changeover switch 61 when three-phase short-circuit driving is performed. In other words, unlike patent document 1 described in the related art, the three-phase short-circuit driving circuit 60 short-circuits the switching elements S4, S5, and S6 of the lower arm group by the output signal from the logic circuit (logic circuit). The three-phase short-circuit driving circuit 60 directly drives the gates of the switching elements S4, S5, and S6 without using an output from the logic circuit.

Accordingly, when the three-phase bridge circuit 20 detects an overvoltage, the vehicle driving device 5 operates the three-phase short-circuit driving circuit 60 to stably perform the three-phase short-circuit driving, and can suppress the overvoltage applied to the three-phase bridge circuit 20. In this way, the three phases of the control motor M1 are respectively stably short-circuited, and the voltage induced from between the winding coils of the motor M1 can be more reliably suppressed.

In the vehicle driving device of patent document 1 described in the background art, for example, the ground level of the switching element of the upper arm varies due to the switching operation of the lower arm, and is therefore unstable. Therefore, in order to operate the switching element of the upper arm by an output signal from a logic circuit (logic circuit), an insulating power supply for grounding the potential of the source of the switching element of the upper arm is required, and the circuit configuration becomes complicated. On the other hand, the vehicle driving device 5 according to the present embodiment does not require an insulating power supply as described above, and can more reliably turn off the switching elements S1, S2, and S3 of the upper arm at the time of three-phase short-circuit driving.

1-2 Action of vehicle drive device

Next, the operation of the vehicle driving device 5 will be described with reference to fig. 4. Fig. 4 is a flowchart showing an example of the operation of the vehicle driving device 5 according to the present embodiment. Fig. 4 shows the operation of the inverter 10 in a state of normal driving. In a normal driving state, the power supply changeover switch 61 is connected to the PWM driving circuit 50. In other words, the step-down DC power supply 70 supplies power to the PWM drive circuit 50. The u-phase is described below, but v-phase and w-phase are the same.

As shown in fig. 4, when the overvoltage detection circuit 80 detects a predetermined overvoltage in the power supply line Lp in a state where the inverter 10 is normally driven (yes in S11), the overvoltage detection circuit 80 outputs a three-phase short-circuit signal to the latch circuit 62. The latch circuit 62 holds a three-phase short-circuit signal and outputs the three-phase short-circuit signal to the power supply changeover switch 61 and the insulating switch 63. Accordingly, the latch circuit 62 switches the power supply switching switch 61 from the PWM driving circuit 50 to the switching element S4 of the lower arm, and operates the discharge circuit 64 connected to the gate of the switching element S1 of the upper arm (S12). In other words, the latch circuit 62 supplies the voltage of the step-down DC power supply 70 to the gate of the switching element S4, and discharges the charge of the gate of the switching element S1. Accordingly, the inverter 10 can more reliably turn off the switching element S1 of the upper arm and more reliably turn on the switching element S4 of the lower arm at the time of three-phase short-circuit driving.

Since the discharge circuit 64 discharges the electric charge on the gate of the switching element S1, both the switching elements S1 and S4 are prevented from being turned on and short-circuiting between the positive and negative electrodes of the battery P1 is prevented when the three-phase short-circuit driving is performed.

When the power supply changeover switch 61 is switched to the three-phase short-circuit state, the driving power is not supplied to the PWM driving circuit 50, and therefore the output side of the PWM driving circuit 50 has high impedance according to the characteristics of the PWM driving circuit 50. Accordingly, when the power supply changeover switch 61 is switched to the switching element S4, the inverter 10 can suppress the problem that the electric power from the step-down DC power supply 70 is introduced into the PWM driving circuit 50 via the resistor element R3, and the gate of the switching element S4 is not turned on. The output side of the PWM driving circuit 50 has high impedance, and is an example in which the gate output of the PWM driving circuit 50 is cut off. The impedance of the output side (the switching element S1 side) when the power for driving is not supplied to the PWM driving circuit 50 is the impedance to the extent that the gate charge of the switching element S1 is discharged via the discharging circuit 64, in other words, the gate charge cannot flow to the PWM driving circuit 50, at the time of three-phase short-circuit driving. The impedance of the output side (the switching element S4 side) when the power for driving is not supplied to the PWM driving circuit 50 is the impedance to the extent that the power from the step-down DC power supply 70 cannot be supplied to the gate of the switching element S4, that is, the PWM driving circuit 50 via the resistor element R3, at the time of three-phase short-circuit driving.

When the discharge circuit 64 is turned on, the discharge circuit 64 and the latch circuit 62 have different potentials, but the insulating switch 63 is connected between the discharge circuit 64 and the latch circuit 62, so that the charge at the gate of the switching element S1 does not flow to the latch circuit 62 side.

In a state where the inverter 10 is normally driven, when the overvoltage detection circuit 80 does not detect a predetermined overvoltage on the power supply line Lp (no in S11), the process is terminated without performing the three-phase short-circuit driving. In other words, the inverter 10 continues the normal driving state.

As described above, the vehicle driving device 5 according to the present embodiment includes: a power supply changeover switch 61 for applying a voltage to the gates of the switching elements S4, S5, S6 of the lower arm at the time of three-phase short-circuit driving; and an insulating switch 63 for shorting the gate-source electrodes of the switching elements S1, S2, S3 of the upper arm at the time of three-phase short-circuit driving.

Accordingly, in the vehicle driving device 5, when the inverter 10 is in the three-phase short-circuit control state by the three-phase short-circuit signal (an example of the command signal for the three-phase short-circuit) from the latch circuit 62, the voltage is applied to the gates of the switching elements S4, S5, S6 of the lower arm by the power supply changeover switch 61, so that the switching elements S4, S5, S6 can be turned on, and the gates and sources of the switching elements S1, S2, S3 of the upper arm can be short-circuited by the insulation switch 63, so that the switching elements S1, S2, S3 can be forcibly turned off. Further, by switching the power supply changeover switch 61, the driving power is not supplied to the PWM driving circuit 50, and the output side of the PWM driving circuit 50 becomes high impedance according to the characteristics of the PWM driving circuit 50, so that the vehicle driving device 5 can stably perform the three-phase short-circuiting.

(Modification of embodiment 1)

The vehicle driving device according to the present modification will be described below with reference to fig. 5 to 7. Fig. 5 is a block diagram showing a functional configuration of one phase in the inverter 10a according to the present modification. Fig. 5 shows a functional configuration of the u-phase in the inverter 10 a. The u-phase is described below, but v-phase and w-phase are the same.

The inverter 10a according to the present modification mainly includes an abnormality detection circuit 90, which is different from the inverter 10 according to embodiment 1. The following description will focus on the configuration of the inverter 10a according to the present modification, which is different from the inverter 10 according to embodiment 1. In this modification, the same or similar configuration as the inverter 10 according to embodiment 1 is given the same reference numerals as the inverter 10, and the description thereof is omitted or simplified.

As shown in fig. 5, the inverter 10a according to the present modification includes an abnormality detection circuit 90 for detecting an abnormality of the microcontroller 40, and thus can perform three-phase short-circuit driving even when a failure occurs in the microcontroller 40. The abnormality detection circuit 90 may be provided in the control circuit 30, for example. The occurrence of a failure in the microcontroller 40 is, for example, a case where an error occurs in the program software of the microcontroller 40, or a case where a part of the program software is out of control.

The abnormality detection circuit 90 is a circuit for detecting an abnormality of the microcontroller 40. Specifically, the abnormality detection circuit 90 is a circuit that detects an abnormality of the microcontroller 40 and outputs a signal for driving the three-phase short-circuit driving circuit 60. The abnormality of the microcontroller 40 is an example of the abnormality of the inverter 10a.

The abnormality detection circuit 90 is described with reference to fig. 6. Fig. 6 is a block diagram showing a functional configuration of the abnormality detection circuit 90 according to the present modification. In fig. 6, the microcontroller 40 periodically outputs a clear pulse signal to the failure notification circuit 91.

As shown in fig. 6, the abnormality detection circuit 90 includes a failure notification circuit 91 and a NOT circuit 92.

The failure notification circuit 91 is a circuit for monitoring whether the microcontroller 40 is defective or not, and is, for example, a monitor clock circuit. The failure notification circuit 91 is considered to be a failure of the microcontroller 40 when the clear pulse signal is NOT received for a predetermined period, and outputs a failure notification signal to the latch circuit 62 and the microcontroller 40 via the NOT circuit 92.

The failure notification signal is a reset signal, and is output as a low-level pulse signal, for example. The low-level pulse signal is inverted by the NOT circuit 92 and is output to the latch circuit 62 as a high-level pulse signal.

The latch circuit 62 holds a signal (for example, a high-level pulse signal, hereinafter sometimes referred to as a notification signal) based on the failure notification signal outputted from the failure notification circuit 91, and outputs the signal to the power supply changeover switch 61 and the insulation switch 63. The signal (notification signal) based on the failure notification signal obtained from the failure detection circuit 90 by the latch circuit 62 is an example of a command signal for a three-phase short circuit.

The microcontroller 40 is restarted by receiving a reset signal as a failure notification signal. When the microcontroller 40 is restarted normally by the reset signal, it outputs an unlock signal for releasing the signal held in the latch circuit 62. When the microcontroller 40 is restarted normally, the vehicle driving device 5 resumes normal driving, but if the vehicle cannot be restarted normally, the signal based on the failure notification signal is continuously output to the power supply changeover switch 61 and the isolation switch 63.

The example in which the three-phase short-circuit driving circuit 60 has the latch circuit 62 has been described above, but the three-phase short-circuit driving circuit 60 is not limited to the latch circuit 62 as long as it can be shifted to the three-phase short-circuit control state when a three-phase short-circuit command from the microcontroller 40, a three-phase short-circuit signal from the overvoltage detecting circuit 80, or a notification signal from the microcontroller 40 is obtained. The three-phase short-circuit driving circuit 60 may have, for example, a logic circuit (for example, an OR circuit) that outputs a signal obtained when at least 1 of the three-phase short-circuit instruction, the three-phase short-circuit signal, and the notification signal is obtained, instead of the latch circuit 62. The three-phase short-circuit driving circuit 60 may have a latch circuit 62 to hold a signal based on the failure notification signal.

Next, the operation of the vehicle driving device according to the present modification will be described with reference to fig. 7. Fig. 7 is a flowchart showing an example of the operation of the vehicle driving device according to the present modification. Fig. 7 shows the operation of the inverter 10a in the normal driving state. In the normal driving state, the power supply changeover switch 61 is connected to the PWM driving circuit 50. In other words, the step-down DC power supply 70 supplies power to the PWM drive circuit 50. The u-phase is described below, but v-phase and w-phase are the same.

As shown in fig. 7, when the abnormality detection circuit 90 detects an abnormality of the microcontroller 40 in the normal driving state (yes in S21), the abnormality detection circuit 90 outputs a signal based on the failure notification signal to the latch circuit 62. The latch circuit 62 holds the failure notification signal (for example, a high-level pulse signal, an example of a signal based on the failure notification signal) inverted by the NOT circuit 92, and outputs the failure notification signal inverted by the NOT circuit 92 to the power supply changeover switch 61 and the insulating switch 63.

Accordingly, the latch circuit 62 switches the power supply switching switch 61 from the PWM driving circuit 50 to the switching element S4 of the lower arm, and operates the discharge circuit 64 connected to the gate of the switching element S1 of the upper arm (S22). In other words, the latch circuit 62 supplies the voltage of the step-down DC power supply 70 to the gate of the switching element S4, and the insulating switch 63 is turned on to discharge the charge of the gate of the switching element S1. Accordingly, when the microcontroller 40 is defective, the inverter 10a can more reliably turn off the switching element S of the upper arm and can more reliably turn off the switching element S4 of the lower arm.

In addition, when the abnormality detection circuit 90 does not detect an abnormality of the microcontroller 40 in the normal driving state (no in S21), the inverter 10a ends the process without performing the three-phase short-circuit driving. In other words, the inverter 10a continues the normal driving state.

As described above, the inverter 10a provided in the vehicle driving device according to the present modification includes the abnormality detection circuit 90 for detecting an abnormality of the microcontroller 40. Accordingly, for example, when it is difficult to suppress an increase in the induced voltage due to abnormality of the microcontroller 40, the vehicle driving device is in a state of three-phase short-circuit control. Thus, the vehicle driving device can suppress an increase in the induced voltage due to an abnormality in the microcontroller 40. In addition, the normal control of the microcontroller 40 includes a normal motor drive torque output control, and a three-phase short circuit control based on a PWM drive signal from the microcontroller 40.

(Embodiment 2)

The vehicle driving device according to the present embodiment will be described below with reference to fig. 8 and 9.

[2-1. Construction of vehicle drive device ]

The configuration of the vehicle driving device according to the present embodiment will be described below with reference to fig. 8. Fig. 8 is a block diagram showing a functional configuration of one phase in the inverter 110 according to the present embodiment. Fig. 8 shows a functional configuration of u-phase in the inverter 110. The u-phase is described below, but v-phase and w-phase are the same.

The inverter 110 according to the present embodiment mainly includes relays 165 and 166, and the output signal from the PWM driving circuit 50 is supplied to the switching elements S1 and S4 via the relays 165 and 166, which are different from the inverter 10 according to embodiment 1. In the following, the inverter 110 according to the present embodiment will be described mainly with respect to differences from the inverter 10 according to embodiment 1. In this embodiment, the same or similar configuration as the inverter 10 according to embodiment 1 is given the same reference numerals as the inverter 10, and the description thereof is omitted or simplified.

As shown in fig. 8, the three-phase short-circuit driving circuit 160 provided in the inverter 110 includes: the power supply changeover switch 161, the latch circuit 62, the insulating switch 63, the discharge circuit 64, the relays 165 and 166, and the resistor elements R1 to R3. In the present embodiment, the PWM driving circuit 50 receives power supply from the step-down DC power supply 70 without passing through the power supply changeover switch 161.

In the power supply changeover switch 161, one end is connected to the step-down DC power supply 70, and the other end is connected to the gate of the switching element S4, to selectively change whether or not to supply the power (voltage) of the step-down DC power supply 70 to the gate of the switching element S4. The power supply changeover switch 161 connects the step-down DC power supply 70 to the gate of the switching element S4 when the vehicle driving device performs three-phase short-circuit driving. The switching of the power supply changeover switch 161 is performed by a three-phase short-circuit signal from the latch circuit 62.

In the relay 165, one end is connected to the PWM driving circuit 50 (for example, a high-side output terminal of the PWM driving circuit 50), and the other end is connected to the gate of the switching element S1, and whether or not to supply the output signal from the PWM driving circuit 50 to the gate of the switching element S1 is selectively switched.

The relay 165 has a switch 165a as a contact, and a coil 165b as a primary winding. The relay 165 turns on or off the switch 165a by a magnetic force generated by a current flowing to the coil 165b. In the present embodiment, the relay 165 has a configuration in which the power supply changeover switch 161 is turned on, so that the current supplied from the step-down DC power supply 70 flows to the coil 165b, and the switch 165a is turned off.

The relay 165 connects the PWM driving circuit 50 to the gate of the switching element S1 when the vehicle driving apparatus is normally driven. The relay 165 releases (cuts off) the connection between the PWM driving circuit 50 and the gate of the switching element S1 when the vehicle driving device performs three-phase short-circuit driving.

Accordingly, the relay 165 can suppress the supply of the output signal from the PWM driving circuit 50 to the gate of the switching element S1 to turn on the switching element S1 when the vehicle driving device performs the three-phase short-circuit driving. In other words, the relay 165 can suppress a short circuit between the positive and negative electrodes of the battery P1 when the vehicle driving device performs three-phase short circuit driving.

In the relay 166, one end is connected to the PWM driving circuit 50 (for example, a low-side output terminal of the PWM driving circuit 50), and the other end is connected to the gate of the switching element S4, and it is selectively switched whether or not to supply the output signal from the PWM driving circuit 50 to the gate of the switching element S4.

The relay 166 has a switch 166a as a contact, and a coil 166b as a primary winding. The relay 166 turns on or off the switch 166a by a magnetic force generated by a current flowing to the coil 166b. In the present embodiment, the relay 166 has a configuration in which the power supply changeover switch 161 is turned on, so that the current supplied from the step-down DC power supply 70 flows to the coil 166b, and the switch 166a is turned off.

The relay 166 connects the PWM driving circuit 50 to the gate of the switching element S4 when the vehicle driving device is normally driven. When the vehicle driving device performs three-phase short-circuit driving, the relay 166 releases (cuts off) the connection between the PWM driving circuit 50 and the gate of the switching element S4.

Accordingly, the relay 166 can supply only the signal (voltage) from the step-down DC power supply 70 to the gate of the switching element S4 in the PWM driving circuit and the step-down DC power supply 70 when the vehicle driving device performs three-phase short-circuit driving.

In addition, when the vehicle driving device performs three-phase short-circuit driving, the relays 165 and 166 are turned off, so that the electrical connection between the PWM driving circuit 50 and the switching elements S1 and S4 can be cut off, and therefore, the output side of the PWM driving circuit 50 can be made high-impedance.

Accordingly, when the power supply changeover switch 161 is turned on, the inverter 110 can suppress the electric power from the step-down DC power supply 70 from being introduced into the PWM driving circuit 50 via the resistor elements R1 and R3, and the gate of the switching element S4 is not turned on. Further, when the power supply changeover switch 161 is turned on, the inverter 110 can suppress the flow of the electric charge passing through the gate to the PWM driving circuit 50, and the gate of the switching element S1 is not turned off. The turning off of the relays 165 and 166 and the cutting off of the electrical connection between the PWM driving circuit 50 and the switching elements S1 and S4 is an example in which the gate output of the PWM driving circuit 50 is cut off.

[2-2. Action of vehicle drive device ]

Hereinafter, the operation of the vehicle driving device will be described with reference to fig. 9. Fig. 9 is a flowchart showing an example of the operation of the vehicle driving device according to the present embodiment. Fig. 9 shows the operation in the state where the inverter 110 is normally driven. In addition, in the normal driving state, the power supply changeover switch 161 is in an off state. In other words, the step-down DC power supply 70 supplies no power (voltage) to the gate of the switching element S4.

As shown in fig. 9, when the overvoltage detection circuit 80 detects a predetermined overvoltage in the power supply line Lp in a state where the inverter 110 is normally driven (yes in S31), the overvoltage detection circuit 80 outputs a three-phase short-circuit signal to the latch circuit 62. The latch circuit 62 holds a three-phase short-circuit signal and outputs the three-phase short-circuit signal to the power supply changeover switch 161 and the insulating switch 63. Accordingly, the latch circuit 62 turns on the power supply changeover switch 161, and operates the discharge circuit 64 connected to the gate of the switching element S1 of the upper arm (S32). In other words, the latch circuit 62 supplies the voltage of the step-down DC power supply 70 to the gate of the switching element S4, and turns on the insulating switch 63 to discharge the charge of the gate of the switching element S1. Accordingly, the inverter 110 can more reliably turn off the switching element S1 of the upper arm and more reliably turn on the switching element S4 of the lower arm at the time of three-phase short-circuit driving.

In a state where the inverter 110 is normally driven, when the overvoltage detection circuit 80 does not detect a predetermined overvoltage in the power supply line Lp (no in S31), the process is terminated without performing the three-phase short-circuit control. In other words, the inverter 110 continues the normal driving state.

As described above, the inverter 110 provided in the vehicle driving device according to the present embodiment includes: a relay 165 having one end connected to the PWM driving circuit 50 and the other end connected to the switching elements S1, S2, and S3 of the upper arm, and a relay 166 having one end connected to the PWM driving circuit 50 and the other end connected to the switching elements S4, S5, and S6 of the lower arm. In addition, when the inverter 110 performs the three-phase short-circuiting operation, the relays 165 and 166 are turned off, and a high impedance can be realized in the path between the PWM driving circuit 50 and the switching elements S1 to S6.

Embodiment 3

The vehicle driving device according to the present embodiment will be described below with reference to fig. 10 and 13.

[3-1. Construction of vehicle drive device ]

Fig. 10 is a circuit diagram illustrating an example of the three-phase bridge circuit 20 provided in the inverter 210 of the vehicle driving device 5 according to the present embodiment. In addition, the voltage Vp shown in fig. 10 is a power supply voltage, and the voltage Vg is a ground voltage. The configuration of the electric vehicle 1 including the vehicle driving device 5 is the same as that of embodiment 1, and the description thereof is omitted.

As shown in fig. 10, the vehicle driving device 5 includes a motor M1, an inverter 210, and a battery P1. Inverter 210 has a three-phase bridge circuit 20 and a control circuit 230. Fig. 10 illustrates a smoothing capacitor C1 for smoothing the voltage applied to the three-phase bridge circuit 20.

The three-phase bridge circuit 20 is a circuit that converts direct current supplied from the battery P1 into three-phase alternating current by switching operation, supplies the three-phase alternating current to the motor M1, and drives the motor M1. The input side for switching control of the three-phase bridge circuit 20 is connected to the three-phase short-circuit switching circuit 250 and the PWM driving circuit 260, the input side of electric power is connected to the battery P1, and the output side is connected to the motor M1.

In addition, at the time of regeneration of the motor M1, a regenerative current is introduced from the output side of the three-phase bridge circuit 20 to the input side of electric power, and the side connected to the battery P1 is defined as the input side and the side connected to the motor M1 is defined as the output side.

The three-phase bridge circuit 20 is formed by connecting a plurality of switching elements S1 to S6 in a three-phase bridge structure. The three-phase bridge circuit 20 has: switching elements S1, S2, and S3 provided in the upper arm group located above fig. 10; and switching elements S4, S5, and S6 provided in the lower arm group located below in fig. 10. For example, the switching elements S1 to S6 are formed of Field Effect Transistors (FETs), insulated Gate Bipolar Transistors (IGBTs), or the like. The switching elements S1 to S6 may be formed using a wide band gap semiconductor.

The switching elements S1, S2, and S3 are connected between 3 output lines led out from three terminals of the motor M1 and a power supply line Lp connected to the positive electrode of the battery P1. Each of the switching elements S4, S5, and S6 is connected between the 3 output lines and the ground line Lg, and the ground line Lg is connected to the negative electrode of the battery P1. The flywheel diodes are connected in parallel to the switching elements S1 to S6. The flywheel diode may be a parasitic diode parasitic to each of the switching elements S1 to S6. In the following, the switching elements S1, S2, and S3 provided in the upper arm group may be referred to as switching elements S1, S2, and S3 of the upper arm, and the switching elements S4, S5, and S6 provided in the lower arm group may be referred to as switching elements S4, S5, and S6 of the lower arm.

The switching elements S1 to S6 are connected to the control circuit 230, and are driven by signals output from the control circuit 230. Specifically, the switching elements S1 to S6 convert the dc power supplied from the battery P1 into three-phase ac power by switching operation based on the signal output from the PWM driving circuit 260, and supply the ac power to the motor M1. The motor M1 is driven in a state of traction, regeneration, coasting, or the like according to the driving of the switching elements S1 to S6. The switching elements S1 to S6 are turned off together by the switching elements S1, S2, S3 of the upper arm, and the switching elements S4, S5, S6 of the lower arm are short-circuited together in three phases, based on the signal output from the three-phase short-circuit switching circuit 250.

The control circuit 230 is a control device for controlling the driving of the switching elements S1 to S6. The control circuit 230 has a microcontroller 240, a three-phase short-circuit switching circuit 250, and a PWM driving circuit 260. Hereinafter, the microcontroller 240 is also referred to as the microcontroller 240.

The microcontroller 240 controls the inverter 210, the inverter 210 being configured to drive the motor M1 mounted on the electric vehicle 1, and the inverter 210 being configured by the three-phase bridge circuit 20 having the plurality of switching elements S1 to S6. The microcontroller 240 is electrically connected to the three-phase short-circuit switching circuit 250, and generates and outputs control signals for controlling the three-phase short-circuit switching circuit 250 and the PWM driving circuit 260, respectively. The microcontroller 240 is configured by a microprocessor that performs various operations and the like, a memory that stores programs, information, and the like for operating the microprocessor, and peripheral circuits.

The microcontroller 240 obtains information detected by various sensors including a current sensor CSu, CSv, CSw that detects a current flowing into the motor M1, a rotational position sensor RS that detects a magnetic pole position of the motor M1 and detects a rotational position, and the like. The current sensor CSu, CSv, CSw is a sensor for detecting current values of u-phase, v-phase, and w-phase of the motor M1. In addition, the microcontroller 240 obtains information about the voltage Vp in the power line Lp. The microcontroller 240 obtains control instruction information such as a torque instruction or a drive regeneration instruction signal, which is output from the outside of the control circuit 230, for example, from the ECU of the electric vehicle 1. The microcontroller 240 obtains the respective pieces of information, for example, via a motor control signal obtaining section (not shown).

Based on the obtained information, the microcontroller 240 converts the torque command value into a current by calculation, and outputs a control signal for controlling the current of the motor M1. For example, the microcontroller 240 calculates a drive signal (for example, a PWM signal described later) necessary for driving the motor M1 so that the torque of the motor M1 at the time of driving the vehicle driving device 5 becomes a target torque (for example, a torque corresponding to an operation amount of an accelerator pedal or a brake pedal of the electric vehicle 1) indicated by torque command information, and outputs the drive signal to the three-phase short-circuit switching circuit 250. The microcontroller 240 outputs the drive signal to the three-phase short-circuit switching circuit 250, thereby controlling the operation of the PWM drive circuit 260 via the three-phase short-circuit switching circuit 250. The microcontroller 240 outputs a drive signal for performing three-phase PWM control when the vehicle drive device 5 is normally driven. The drive signal is a control signal for current control of the motor M1.

The microcontroller 240 is an example of a signal generating unit that generates a drive signal. The signal generating unit is not limited to the microcontroller 240, and may be a microprocessor, a CPU (central processing unit), or the like.

In order to suppress overvoltage applied to the inverter 210 when the inverter 210 is abnormal, the three-phase short-circuit switching circuit 250 performs a three-phase short circuit in which the switching elements S4, S5, and S6 of the lower arm are short-circuited together among the plurality of switching elements S1 to S6. Specifically, the three-phase short-circuit switching circuit 250 turns off the switching elements S1, S2, and S3 (switching elements of the upper arm) and turns on the switching elements S4, S5, and S6 (switching elements of the lower arm) when the inverter 210 is abnormal.

Accordingly, the induced voltage generated from the motor M1 becomes almost 0 (zero), so that the overvoltage of the three-phase bridge circuit 20 can be suppressed. The overvoltage may be caused by, for example, disconnection of the positive-side wiring of the battery P1, disconnection of a main relay, not shown, provided in the battery P1, or the like.

In the present embodiment, the abnormality of the inverter 210 is described as an example of an overvoltage state in which an overvoltage is generated in the inverter 210, in other words, the voltage of the battery P1 exceeds a predetermined voltage, but the present invention is not limited thereto.

The three-phase short-circuit switching circuit 250 includes a logic circuit that outputs driving signals for driving the plurality of switching elements S1 to S6 to the PWM driving circuit 260.

The configuration and the like of the three-phase short-circuit switching circuit 250 will be described in detail with reference to fig. 11A and 11B. Fig. 11A is a block diagram showing a functional configuration of one phase in the inverter 210 according to the present embodiment. Fig. 11A shows a functional configuration of the u-phase in the inverter 210. The u-phase is described below, but v-phase and w-phase are the same.

As shown in fig. 11A, the inverter 210 has a step-down DC power supply 70, an overvoltage detection circuit 80, and a relay 290 in addition to the control circuit 230. The three-phase short-circuit switching circuit 250 includes an AND circuit 251, an OR circuit 252, an AND circuit 253, a latch circuit 254, AND a NOT circuit 255.

The AND circuit 251 receives the PWM signal from the high side (H side) of the microcontroller 240 AND the signal from the latch circuit 254, AND outputs a signal for controlling the PWM driving circuit 260 based on the received signals. In the AND circuit 251, one end of an input terminal is connected to a high-side terminal (the "H side" in fig. 11A) of the microcontroller 240, AND the other end of the input terminal is connected to the latch circuit 254. In addition, in the AND circuit 251, an output terminal is connected to the PWM driving circuit 260.

The AND circuit 251 outputs the PWM signal as it is to the PWM drive circuit 260 during normal operation, AND outputs the drive signal for turning off the switching element S1 of the upper arm during three-phase short-circuit operation to the PWM drive circuit 260. The AND circuit 251 outputs a signal (e.g., a high-level signal) when receiving signals (e.g., high-level signals) from both the microcontroller 240 AND the latch circuit 254. In the present embodiment, the signal output from the AND circuit 251 to the PWM driving circuit 260 is an example of an upper arm driving signal.

In normal driving, a high-level signal is output from the latch circuit 254, for example. At this time, the AND circuit 251 outputs a high-level signal to the PWM driving circuit 260 when the PWM signal is at a high level, AND outputs a low-level signal to the PWM driving circuit 260 when the PWM signal is at a low level.

The AND circuit 251 is an example of the 1 st logic circuit. The 1 st logic circuit is not limited to the AND circuit 251, AND may have one or more other logic circuits as long as it can output the PWM signal as it is to the PWM driving circuit 260 during normal operation AND can output the driving signal for turning off the switching element S1 of the upper arm to the PWM driving circuit 260 during three-phase short-circuit operation.

The OR circuit 252 receives the PWM signal from the low-side terminal (L side in fig. 11A) of the microcontroller 240 and the signal from the latch circuit 254, and outputs a signal for controlling the PWM driving circuit 260 based on the received signals. In the OR circuit 252, one end of an input terminal is connected to a low-side terminal (the "L side" in fig. 11A) of the microcontroller 240, and the other end of the input terminal is connected to the latch circuit 254 via the NOT circuit 255. In the OR circuit 252, an output terminal is connected to the PWM driving circuit 260.

The OR circuit 252 outputs the PWM signal as it is to the PWM drive circuit 260 during normal operation, and outputs a drive signal for turning on the switching element S4 of the lower arm to the PWM drive circuit 260 during three-phase short-circuit operation. The OR circuit 252 outputs a signal (e.g., a high-level signal) when receiving a signal (e.g., a high-level signal) from at least one of the microcontroller 240 and the latch circuit 254, for example. In the OR circuit 252, a signal output from the OR circuit 252 to the PWM driving circuit 260 is an example of a lower arm driving signal.

In normal driving, a high-level signal is output from the latch circuit 254, for example. Accordingly, the OR circuit 252 outputs a low-level signal from the NOT circuit 255 during normal driving, outputs a high-level signal to the PWM driving circuit 260 when the PWM signal is at a high level, and outputs a low-level signal to the PWM driving circuit 260 when the PWM signal is at a low level.

The OR circuit 252 is an example of the 2 nd logic circuit. The 2 nd logic circuit is not limited to the OR circuit 252, and may be configured to have one OR more other logic circuits as long as the PWM signal is output as a drive signal to the PWM drive circuit 260 during normal operation and the drive signal for turning on the switching element S4 of the lower arm is output to the PWM drive circuit 260 during three-phase short-circuit operation.

The AND circuit 253 receives the drive signals (for example, the upper arm drive signal AND the lower arm drive signal) from the AND circuit 251 AND the OR circuit 252, AND detects whether OR not a failure has occurred in the internal signal of the three-phase short-circuit switching circuit 250 based on the received drive signals. The internal signal generation failure in the three-phase short-circuit switching circuit 250 is a state in which a high-level signal is input to both the high side and the low side of the PWM driving circuit 260. The reason for this may be, for example, that at least 1 of the plurality of logic circuits included in the three-phase short-circuit switching circuit 250 has a failure, that a wiring pattern short-circuit occurs in the substrate of the three-phase short-circuit switching circuit 250, or the like. In the AND circuit 253, one end of an input terminal is connected to an output terminal of the AND circuit 251, AND the other end of the input terminal is connected to an output terminal of the OR circuit 252. In addition, in the AND circuit 253, an output terminal is connected to the microcontroller 240 AND the relay 290. The output terminal of the AND circuit 253 may be connected to at least the relay 290.

The AND circuit 253 outputs a simultaneous conduction detection signal indicating that the switching elements S1 AND S4 are simultaneously on when a high-level drive signal is input from both the AND circuit 251 AND the OR circuit 252, for example. The AND circuit 253 does not output the simultaneous conduction detection signal when a low-level drive signal is input to one OR both of the AND circuit 251 AND the OR circuit 252, for example.

In the present embodiment, the control of the microcontroller 240 does not generate a high-level drive signal output from both the AND circuit 251 AND the OR circuit 252. When the high-level drive signals are output from both the AND circuit 251 AND the OR circuit 252, the PWM drive circuit 260 turns on both the switching elements S1 AND S4, because a short circuit occurs between the upper AND lower sides at this time. In other words, when the high-level drive signals are output from both the AND circuit 251 AND the OR circuit 252, it can be presumed that at least 1 of the plurality of logic circuits included in the three-phase short-circuit switching circuit 250 has failed. The AND circuit 253 outputs the simultaneous conduction detection signal to the microcontroller 240 AND the relay 290 when the high-level drive signals are output from both the AND circuit 251 AND the OR circuit 252. When detecting that the upper arm drive signal AND the lower arm drive signal are both on, the AND circuit 253 outputs the simultaneous on detection signal, AND causes the relay 290 to operate as follows, thereby cutting off the output of the PWM drive circuit 260 to the plurality of switching elements S1 to S6. The AND circuit 253 is an example of a monitor circuit, AND the simultaneous conduction detection signal output from the AND circuit 253 to the microcontroller 240 is an example of a detection result. The AND circuit 253 may output the simultaneous conduction detection signal to at least the relay 290.

The three-phase short-circuit switching circuit 250 is not limited to have the AND circuit 253. The three-phase short-circuit switching circuit 250 may not have the AND circuit 253, for example.

In the latch circuit 254, an input side is connected to the microcontroller 240 AND the overvoltage detection circuit 80, an output side is connected to the AND circuit 251 AND to the OR circuit 252 via the NOT circuit 255, AND a three-phase short-circuit signal output from the overvoltage detection circuit 80 is held, AND output to the AND circuit 251 AND output to the OR circuit 252 via the NOT circuit 255. In other words, the output of the latch circuit 254 is input to the AND circuit 251 AND is input to the OR circuit 252 via the NOT circuit 255. In addition, in the case where the microcontroller 240 has a function of outputting a three-phase short-circuit instruction, the latch circuit 254 can hold the three-phase short-circuit instruction output from the microcontroller 240, output to the AND circuit 251, AND output to the OR circuit 252 via the NOT circuit 255. The three-phase short-circuit signal and the three-phase short-circuit command are examples of command signals for three-phase short-circuit.

In the present embodiment, the latch circuit 254 is configured to output a signal during normal driving and to stop outputting a signal during three-phase short-circuit driving. The latch circuit 254 maintains the output of the stop signal until the unlock signal is obtained from the microcontroller 240, for example, when a three-phase short-circuit signal or a three-phase short-circuit command is obtained. The signal from the latch circuit 254 may be said to be an active Low (active L in fig. 11A) which is a signal for performing three-phase short-circuit driving when a three-phase short-circuit signal or a three-phase short-circuit command is obtained, for example.

The latch circuit 254 is not limited to output of the stop signal (for example, is not limited to active Low) when the three-phase short-circuit signal or the three-phase short-circuit command is obtained, and may be configured to output of the start signal. The configuration of latch circuit 254 can be appropriately determined according to the configuration of the logic circuit of three-phase short-circuit switching circuit 250.

In the NOT circuit 255, an input terminal is connected to the latch circuit 254, an output terminal is connected to an input terminal of the OR circuit 252, and a signal is output when a signal from the latch circuit 254 is NOT input.

The PWM driving circuit 260 receives power from the step-down DC power supply 70 via the relay 290, and controls driving of the plurality of switching elements S1 to S6 based on a PWM signal (an example of a driving signal) output from the microcontroller 240. The PWM driving circuit 260 converts the dc power supplied from the battery P1 into three-phase ac power, and controls the switching operation of each of the switching elements S1 to S6 so as to supply the ac power to the motor M1. The PWM driving circuit 260 drives the plurality of switching elements S1 to S6 based on the PWM signal outputted from the microcontroller 240. The PWM driving circuit 260 is configured to be able to output electric power (for example, electric power for maintaining a gate potential) for operating the plurality of switching elements S1 to S6.

The PWM driving circuit 260 turns on the switching element S1 when the driving signal of the high level is obtained from the AND circuit 251. The PWM driving circuit 260 turns on the switching element S4 when a high-level driving signal is obtained from the OR circuit 252.

In addition, since the PWM driving circuit 260 does not supply the driving power to the PWM driving circuit 260 when the relay 290 is turned off and the power supply from the step-down DC power supply 70 is stopped, the output side of the PWM driving circuit 260 has a high impedance according to the characteristics of the PWM driving circuit 260. This is an example of cutting off the gate output of the PWM driving circuit 260.

The step-down DC power supply 70 is a power supply for driving the PWM driving circuit 260. The step-down DC power supply 70 supplies a voltage of about 12V to 15V to the PWM driving circuit 260, for example. In the present embodiment, the step-down DC power supply 70 further supplies power to the PWM driving circuit 260 to turn on the switching element S4 of the lower arm when the three-phase short-circuit driving is performed. In other words, the step-down DC power supply 70 supplies power to the PWM driving circuit 260 both when normal driving is performed and when three-phase short-circuit driving is performed. The step-down DC power supply 70 is an example of a power supply of the PWM driving circuit 260.

The step-down DC power supply 70 is a power supply based on at least one of a battery P1 for driving the motor M1 and a low-voltage direct-current battery lower in voltage than the battery P1 for supplying electric power to electric components of the electric vehicle 1. As shown in fig. 11A, the step-down DC power supply 70 is a power supply that steps down the voltage of the battery P1 by a DC/DC converter. The step-down DC power supply 70 may be a low-voltage direct-current battery, that is, a battery P2 (see fig. 11B). In this case, the low-voltage direct-current battery may be, for example, a 12V storage battery. The low-voltage dc battery is an example of the 2 nd dc battery. Further, fig. 11B is a block diagram of one embodiment of a buck DC power supply 70.

In the case where the step-down DC power supply 70 is a power supply based on both the battery P1 and the battery P2 of the low-voltage direct-current battery, the output of the DC/DC converter 71 that steps down the voltage of the battery P1 and the battery P2 may be connected to the relay 290 through a diode OR, as shown in fig. 11B. For example, power may be supplied from a battery on the side of a diode with a high voltage via the relay 290.

The overvoltage detection circuit 80 is a circuit for detecting a predetermined overvoltage of the dc voltage in the three-phase bridge circuit 20. The overvoltage detection circuit 80 detects, for example, a predetermined overvoltage in the power supply line Lp. More specifically, the overvoltage detection circuit 80 outputs a three-phase short-circuit signal for performing a three-phase short-circuit when a predetermined overvoltage in the power supply line Lp is detected. The three-phase short-circuit signal may be a signal indicating that an overvoltage is detected. The overvoltage detection circuit 80 is electrically connected to the power supply line Lp and the ground line Lg, respectively.

The predetermined overvoltage is a voltage predetermined as a voltage that does not exceed the tolerable voltage of the components constituting the circuit. The components constituting the circuit are, for example, switching elements S1 to S6 of the three-phase bridge circuit 20, a smoothing capacitor C1, and the like. The overvoltage detection circuit 80 outputs a three-phase short-circuit signal to the three-phase short-circuit switching circuit 250. In addition, the overvoltage detection circuit 80 may output a three-phase short-circuit signal to the microcontroller 240. The three-phase short-circuit signal is, for example, a pulse signal of a high level, but may not be limited thereto.

The circuit configuration of the overvoltage detection circuit 80 is not particularly limited as long as it can detect an overvoltage and can output a signal indicating that the overvoltage is detected. The overvoltage detection circuit 80 includes, for example, a plurality of resistor elements and a comparator circuit. The comparison circuit includes: a +input terminal, -an input terminal, and an output terminal outputting a result of comparing the voltage of the +input terminal with the voltage of the-input terminal. The comparison circuit outputs a three-phase short-circuit signal from the output terminal, for example, when the detection voltage inputted to the +input terminal is higher than the reference voltage inputted to the-input terminal. The detection voltage is a voltage to be a target for determining whether or not the overvoltage is generated, and is, for example, a voltage based on the voltage Vp on the power supply line Lp. The reference voltage is a voltage that becomes a reference for detecting an overvoltage, for example, a voltage based on a voltage (for example, 5V) in a constant voltage source. In addition, a plurality of resistance elements are used to divide the voltage Vp and the voltage in the constant voltage source.

The relay 290 switches between conduction and non-conduction between the step-down DC power supply 70 and the PWM driving circuit 260. In other words, the relay 290 switches whether or not the power from the step-down DC power supply 70 is supplied to the PWM driving circuit 260. The switching of the relay 290 is performed based on a signal from the AND circuit 253. Relay 290 is an example of a cut-off circuit. The off state of the relay 290 is an example of shutting off the output of the PWM driving circuit 260 to the plurality of switching elements S1 to S6.

Relay 290 has a switch 290a as a contact and a coil 290b as a primary winding. Relay 290 turns on or off switch 290a by a magnetic force generated by flowing a current to coil 290b. In the present embodiment, the relay 290 has a structure in which the signal current output from the AND circuit 253 flows to the coil 290b, AND the switch 290a is turned off. The switch 290a is an example of a cut-off switch for cutting off the power supply from the step-down DC power supply 70 to the PWM driving circuit 260.

The relay 290 connects the PWM driving circuit 260 and the step-down DC power supply 70 when the vehicle driving device 5 is normally driven. When the vehicle driving device 5 performs three-phase short-circuit driving, the relay 290 releases (cuts off) the connection between the PWM driving circuit 260 and the step-down DC power supply 70.

Accordingly, when at least 1 of the logic circuits of the three-phase short-circuit switching circuit 250 fails and the switching elements S1 and S4 cannot be controlled normally based on the PWM signal from the microcontroller 240, the switching elements S1 and S4 can be turned off, for example. In other words, when both the AND circuit 251 of the three-phase short-circuit switching circuit 250 AND the output of the OR circuit 252 are input to the OR circuit 252 as high-level signals, the relay 290 can suppress a short circuit between the positive AND negative electrodes of the battery P1. The cause of this may be, for example, a failure of at least 1 of the plurality of logic circuits included in the three-phase short-circuit switching circuit 250.

As shown in fig. 11A, the PWM driving circuit 260 is connected to the gate of the switching element S1 via the resistive element R1. The PWM driving circuit 260 is connected to the gate of the switching element S4 via the resistive element R2. In other words, in the resistor element R1, one terminal is connected to the PWM driving circuit 260, and the other terminal is connected to the gate of the switching element S1. In the resistor R2, one terminal is connected to the PWM driving circuit 260, and the other terminal is connected to the gate of the switching element S4.

As described above, the three-phase short-circuit switching circuit 250 has logic circuits (for example, the AND circuit 251 AND the OR circuit 252) for controlling the switching elements S1 to S6. In addition, a three-phase short-circuit switching circuit 250 is electrically connected between the microcontroller 240 and the PWM driving circuit 260. In other words, the vehicle driving device 5 does not directly drive the plurality of switching elements S1 to S6 by the output signal from the logic circuit as in patent document 1 described in the related art. The vehicle driving device 5 directly drives the plurality of switching elements S1 to S6 by the output signal from the PWM driving circuit 260.

Thus, for example, when the three-phase bridge circuit 20 detects an overvoltage, the vehicle driving device 5 operates the three-phase short-circuit switching circuit 250 to stably perform the three-phase short-circuit driving, and can suppress the overvoltage applied to the three-phase bridge circuit 20. In this way, the vehicle driving device 5 can more reliably suppress the voltage induced from between the winding coils of the motor M1 by stably shorting the three phases of the motor M1.

In the vehicle driving device of patent document 1 described in the related art, for example, the potential of the source of the switching element of the upper arm fluctuates due to the switching operation of the lower arm, and is therefore unstable. Therefore, in order to operate the switching element of the upper arm by the output signal from the logic circuit, an insulating power supply for grounding the potential of the source of the switching element of the upper arm is required, and the circuit configuration becomes complicated. On the other hand, the vehicle driving device 5 according to the present embodiment does not require an insulating power supply as described above, and can more reliably turn off the switching elements S1, S2, S3 of the upper arm at the time of three-phase short-circuit driving.

As described above, the three-phase short-circuit switching circuit 250 further includes the AND circuit 253, AND among the drive signals output to the PWM drive circuit 260, the drive signal output from the AND circuit 251 that drives the upper arm AND the drive signal output from the OR circuit 252 that drives the lower arm are input to the AND circuit 253. When detecting that 2 drive signals are simultaneously on (for example, signals at high level), the AND circuit 253 turns off the power supply to the PWM drive circuit 260, thereby operating the relay 290 AND cutting off the output of the PWM drive circuit 260 to the plurality of switching elements S1 to S6. The AND circuit 253 may operate the relay 290 when, for example, the switching element of the upper arm AND the switching element of the lower arm are simultaneously turned on AND in a short-circuited state.

For example, the drive signal includes: an upper arm drive signal for driving the switching elements S1, S2, S3 of the upper arm and a lower arm drive signal for driving the switching elements S4, S5, S6 of the lower arm among the plurality of switching elements S1 to S6. The three-phase short-circuit switching circuit 250 has a logic circuit including: the upper arm drive signal is output to the AND circuit 251 (an example of the 1 st logic circuit) of the PWM drive circuit 260, AND the lower arm drive signal is output to the OR circuit 252 (an example of the 2 nd logic circuit) of the PWM drive circuit 260. The three-phase short-circuit switching circuit 250 further includes an AND circuit 253 (an example of a monitor circuit), AND an upper arm drive signal output from the AND circuit 251 AND a lower arm drive signal output from the OR circuit 252 are input to the AND circuit 253. The AND circuit 253 is electrically connected to the microcontroller 240 AND a relay 290 (an example of a cut-off circuit) for cutting off power supply to the PWM driving circuit 260. When detecting that the upper arm drive signal AND the lower arm drive signal are signals for turning on the switching elements of the upper AND lower arms simultaneously, the AND circuit 253 causes the relay 290 to operate as follows, AND cuts off the power supply to the PWM drive circuit 260.

Thus, in the case where a failure occurs in a component (for example, at least 1 of the logic circuits) or the substrate or the like included in the three-phase short-circuit switching circuit 250, and a signal for simultaneously turning on the switching elements of the upper and lower arms is output, the vehicle driving device 5 can suppress simultaneous turning on of the switching elements of the upper and lower arms and occurrence of a short circuit between the upper and lower arms.

As described above, the vehicle driving device 5 includes: a microcontroller 240 that outputs a PWM signal for controlling an inverter 210, the inverter 210 being configured to drive a three-phase motor mounted on the electric vehicle 1, the plurality of switching elements S1 to S6 in the inverter 210 being connected in a three-phase bridge configuration; a PWM circuit 260 driving the plurality of switching elements S1 to S6 according to the PWM signal; and a three-phase short-circuit switching circuit 250 that performs a three-phase short circuit when the inverter 210 is abnormal, the three-phase short circuit being a short circuit of the switching elements S4 to S6 of the lower arm together. The three-phase short-circuit switching circuit 250 is electrically connected between the microcontroller 240 and the PWM driving circuit 260, and outputs a PWM signal as a driving signal to the PWM driving circuit 260 during normal operation, and outputs a driving signal to the PWM driving circuit 260, which turns on the switching elements S4 to S6 of the lower arm and turns off the switching elements S1 to S3 of the upper arm when a command signal for three-phase short-circuit is input.

Thus, the vehicle driving device 5 drives the plurality of switching elements S1 to S6 based on the output signal output from the PWM driving circuit 260, for example, in response to the driving signal from the three-phase short-circuit switching circuit 250. The vehicle driving device 5 can more reliably drive the plurality of switching elements S1 to S6 than in the case of driving the plurality of switching elements S1 to S6 based on a signal output from a circuit that is difficult to output electric power (for example, maintenance gate potential electric power) for operating the switching elements S1 to S6. Thus, the vehicle driving device 5 can stably implement a three-phase short circuit.

[3-2. Action of vehicle drive device ]

Next, the operation of the vehicle driving device 5 will be described with reference to fig. 12 and 13. First, a three-phase short-circuiting operation of the vehicle driving device 5 will be described with reference to fig. 12. Fig. 12 is a flowchart showing an example of the 1 st operation of the vehicle driving device 5 according to the present embodiment. Fig. 12 shows an operation in a state where the inverter 210 is normally driven. In addition, in the normal driving state, the switch 290a of the relay 290 is turned on. In other words, the step-down DC power supply 70 supplies power to the PWM drive circuit 260. The u-phase is described below, but v-phase and w-phase are the same.

As shown in fig. 12, when the overvoltage detection circuit 80 detects a predetermined overvoltage in the power supply line Lp in a state where the inverter 210 is normally driven (yes in S111), the overvoltage detection circuit 80 outputs a three-phase short-circuit signal to the latch circuit 254 (S112). The latch circuit 254 holds the three-phase short-circuit signal, AND outputs the three-phase short-circuit signal to the AND circuit 251 AND the OR circuit 252. In the present embodiment, when the overvoltage detection circuit 80 detects a predetermined overvoltage, the signal from the latch circuit 254 becomes an active Low (active L in fig. 11A), which is a signal for performing three-phase short-circuit driving.

Accordingly, the latch circuit 254 prohibits the output of the high-level signal from the AND circuit 251 to the PWM drive circuit 260, AND outputs the high-level signal from the OR circuit 252 to the PWM drive circuit 260, independently of the PWM signal output from the microcontroller 240 to the OR circuit 252, at the time of three-phase short-circuit driving. In other words, the latch circuit 254 turns off the switching element S1 of the upper arm and turns on the switching element S4 of the lower arm at the time of three-phase short-circuit driving (S113).

When the overvoltage detection circuit 80 does not detect a predetermined overvoltage in the power supply line Lp in a state where the inverter 210 is normally driven (no in S111), the process is terminated without performing the three-phase short-circuit driving. In other words, the inverter 210 continues the state of normal driving.

As described above, the vehicle driving device 5 according to the present embodiment includes the three-phase short-circuit switching circuit 250 electrically connected between the microcontroller 240 and the PWM driving circuit 260. The PWM driving circuit 260 drives the plurality of switching elements S1 to S6. The three-phase short-circuit switching circuit 250 outputs the PWM signal as it is to the PWM driving circuit 260 during normal operation, and outputs the driving signal for turning on the switching elements S4, S5, S6 of the lower arm of the plurality of switching elements S1 to S6 and turning off the switching elements S1, S2, S3 of the upper arm of the plurality of switching elements S1 to S6 to the PWM driving circuit 260 when the three-phase short-circuit signal is input (during three-phase short-circuit driving).

Accordingly, the plurality of switching elements S1 to S6 are controlled by the PWM driving circuit 260. Unlike a logic circuit, the PWM driving circuit 260 can output electric power that normally maintains the gate potential of the switching element. Thus, the vehicle driving device 5 can stably perform the three-phase short circuit, as compared with the case where the switching element is turned on and off based on the output from the logic circuit that is difficult to output electric power that normally maintains the gate potential of the switching element.

Next, a three-phase short-circuiting operation of the vehicle driving device 5 will be described with reference to fig. 13. Fig. 13 is a flowchart showing an example of the 2 nd operation of the vehicle driving device 5 according to the present embodiment. Fig. 13 shows an operation in a state where the inverter 210 is normally driven or three-phase short-circuit driven. In addition, in the normal driving or the three-phase short-circuit driving state, the switch 290a of the relay 290 is turned on. In other words, the buck DC power supply 70 supplies power to the PWM drive circuit 260. The u-phase is described below, but v-phase and w-phase are the same.

As shown in fig. 13, when the AND circuit 253 detects a signal that the switching element S1 AND the switching element S4 are simultaneously turned on in a state where the inverter 210 is normally driven or three-phase short-circuit driven (yes in S121), the AND circuit 253 outputs a signal for turning off the switching elements S1 AND S4 of the upper AND lower arms to the relay 290 (S122). The signal may be any signal that can turn off the relay 290. The signal is the simultaneous conduction detection signal. In the present embodiment, the AND circuit 253 outputs the signal to the microcontroller 240 in step S122, but the present invention is not limited to this. The AND circuit 253 outputs the signal to the microcontroller 240 as an example of the output detection result.

The relay 290 is turned off when the signal is obtained from the AND circuit 253. Thus, the supply of power from the step-down DC power supply 70 to the PWM driving circuit 260 is stopped. In other words, the gate voltage is not supplied from the PWM driving circuit 260 to the switching elements S1 and S4. In other words, the AND circuit 253 outputs the signal to turn off the upper arm switching element S1 AND the lower arm switching element S4 (S123).

Further, the microcontroller 240, upon obtaining the signal from the AND circuit 253, may prohibit the output of the three-phase short-circuit instruction to the three-phase short-circuit switching circuit 250. In other words, the microcontroller 240 may perform control not to implement the three-phase short-circuit driving.

When the signal is obtained from the AND circuit 253, the microcontroller 240 notifies the upper ECU of the detection of the signal that the switching elements of the upper AND lower arms are simultaneously turned on (S124). When this signal is obtained, the host ECU may perform control to lower the rotation speed of the motor M1 (i.e., the speed of the electric vehicle 1), for example. The microcontroller 240 notifies the upper ECU of the detection of the simultaneous on signal at step S124, and outputs a signal for limiting the rotation speed of the motor M1.

When the AND circuit 253 does not detect a signal to turn on both the switching element S1 AND the switching element S4 in the normal driving state or the three-phase short-circuit driving state of the inverter 210 (no in S121), the processing is terminated without turning off the switching elements S1 AND S4 of the upper AND lower arms. In other words, the inverter 210 continues the normal driving or the three-phase short-circuit driving.

As described above, the control method of the vehicle driving device 5 according to the present embodiment includes the 1 st step of detecting a signal for simultaneously turning on the switching elements (for example, the switching elements S1 and S4) of the upper and lower arms; and step 2, when the signal which is simultaneously turned on is detected, the switching elements of the upper and lower arms are turned off. The step 2 includes a step of cutting off the power supplied to the PWM driving circuit 260, and the PWM driving circuit 260 drives the switching elements of the upper and lower arms.

Accordingly, when the three-phase short-circuit switching circuit 250 fails and a signal for turning on the switching elements of the upper and lower arms simultaneously is output, the vehicle driving device 5 can suppress the switching elements of the upper and lower arms from being turned on simultaneously, in other words, short-circuiting between the positive and negative electrodes of the battery P1.

(Modification of embodiment 3)

The vehicle driving device according to the present modification will be described below with reference to fig. 14 to 16. Fig. 14 is a block diagram showing a functional configuration of one phase in inverter 210a according to the present modification. Fig. 14 shows a functional configuration of the u-phase in the inverter 210 a. The u-phase is described below, but v-phase and w-phase are the same.

The inverter 210a according to the present modification mainly includes an abnormality detection circuit 300, which is different from the inverter 210 according to embodiment 3. The inverter 210a according to the present modification will be described below mainly with respect to differences from the inverter 210 according to embodiment 3. In this modification, the same or similar configuration as the inverter 210 according to embodiment 3 is denoted by the same reference numerals as the inverter 210, and the description thereof is omitted or simplified.

As shown in fig. 14, the inverter 210a according to the present modification includes an abnormality detection circuit 300 that detects an abnormality of the microcontroller 240, and can perform three-phase short-circuit driving even when a failure occurs in the microcontroller 240. The abnormality detection circuit 300 may be provided in the control circuit 230, for example. The case where the microcontroller 240 is defective is, for example, a case where the program software of the microcontroller 240 is erroneous or a case where a part of the program software is out of control.

The abnormality detection circuit 300 is a circuit for detecting an abnormality of the microcontroller 240. Specifically, the abnormality detection circuit 300 is a circuit that detects an abnormality of the microcontroller 240 and outputs a signal for driving the three-phase short-circuit switching circuit 250. The abnormality of the microcontroller 240 is an example of the abnormality of the inverter 210 a.

The abnormality detection circuit 300 is described below with reference to fig. 15. Fig. 15 is a block diagram showing a functional configuration of the abnormality detection circuit 300 according to the present modification. In fig. 15, the microcontroller 240 periodically outputs a clear pulse signal to the failure notification circuit 301.

As shown in fig. 15, the abnormality detection circuit 300 has a failure notification circuit 301 and a NOT circuit 302.

The failure notification circuit 301 is a monitoring circuit that monitors whether or not the microcontroller 240 is defective, and is, for example, a monitoring clock circuit. The failure notification circuit 301, when receiving no clear pulse signal for a predetermined period, recognizes that the microcontroller 240 is defective, and outputs a failure notification signal to the latch circuit 254 and the microcontroller 240 via the NOT circuit 302.

The failure notification signal is a reset signal, and is output as a low-level pulse signal, for example. The low-level pulse signal is inverted by the NOT circuit 302 and is output to the latch circuit 254 as a high-level pulse signal.

The latch circuit 254 holds a signal (for example, a high-level pulse signal, hereinafter sometimes referred to as a notification signal) based on the failure notification signal output from the failure notification circuit 301, outputs the signal to the AND circuit 251, AND outputs the signal to the OR circuit 252 via the NOT circuit 255. The signal based on the failure notification signal obtained from the failure detection circuit 300 by the latch circuit 254 is an example of a command signal for a three-phase short circuit.

The microcontroller 240 is restarted by receiving a reset signal as a failure notification signal. When the microcontroller 240 is restarted normally by the reset signal, an unlock signal for releasing the signal held in the latch circuit 254 is output. When the microcontroller 240 is restarted normally, the vehicle driving device 5 resumes normal driving, but if the normal restart is NOT possible, the signal based on the failure notification signal is continuously output to the AND circuit 251 AND is output to the OR circuit 252 via the NOT circuit 255.

Although the example in which the three-phase short-circuit switching circuit 250 has the latch circuit 254 has been described above, the state in which the three-phase short-circuit switching circuit 250 can be shifted to the three-phase short-circuit control when a three-phase short-circuit command from the microcontroller 240, a three-phase short-circuit signal from the overvoltage detection circuit 80, or a notification signal from the microcontroller 240 is obtained is not limited to the latch circuit 254. The three-phase short-circuit switching circuit 250 may replace the latch circuit 254, for example, have a logic circuit (for example, an OR circuit) that outputs a signal obtained when at least 1 of the three-phase short-circuit instruction, the three-phase short-circuit signal, and the notification signal is obtained. The three-phase short-circuit switching circuit 250 may have a latch circuit 254 to hold a signal based on the failure notification signal.

The operation of the vehicle driving device according to the present modification will be described below with reference to fig. 16. Fig. 16 is a flowchart showing an example of the operation of the vehicle driving device according to the present modification. Fig. 16 shows an operation in a state where the inverter 210a is normally driven. In addition, in the normal driving state, the switch 290a of the relay 290 is turned on. In other words, the step-down DC power supply 70 supplies power to the PWM drive circuit 260. The u-phase is described below, but v-phase and w-phase are the same.

As shown in fig. 16, when the abnormality detection circuit 300 detects an abnormality of the microcontroller 240 in a state where the inverter 210a is normally driven (yes in S131), the abnormality detection circuit 300 outputs a signal based on the failure notification signal to the latch circuit 254. The latch circuit 254 holds a failure notification signal (for example, a high-level pulse signal, an example of a notification signal) inverted by the NOT circuit 302, outputs the notification signal, which is the failure notification signal inverted by the NOT circuit 302, to the AND circuit 251, AND outputs the notification signal to the OR circuit 252 via the NOT circuit 255 (S132).

The latch circuit 254 stops the output of the drive signal from the AND circuit 251 AND outputs the drive signal from the OR circuit 252 when the notification signal is obtained. When the notification signal is obtained, the latch circuit 254 turns off the switching element of the upper arm and turns on the switching element of the lower arm (S133). In other words, the latch circuit 254 performs three-phase short-circuit driving.

In addition, when the abnormality detection circuit 300 does not detect an abnormality of the microcontroller 240 in the normal driving state (no in S131), the inverter 210a ends the process without performing the three-phase short-circuit driving. In other words, the inverter 210a continues the normal driving state.

As described above, the inverter 210a provided in the vehicle driving device according to the present modification includes the abnormality detection circuit 300 for detecting an abnormality of the microcontroller 240. Accordingly, when the vehicle driving device cannot normally control due to an abnormality of the microcontroller 240, for example, and it is difficult to suppress an increase in the induced voltage, the vehicle driving device is in a three-phase short-circuit control state. Thus, the vehicle driving device can suppress an increase in the induced voltage due to the occurrence of an abnormality in the microcontroller 240. The normal control of the microcontroller 240 includes normal motor drive torque output control and three-phase short-circuit control by PWM drive signals from the microcontroller 240.

Embodiment 4

The vehicle driving device according to the present embodiment will be described below with reference to fig. 17 and 18.

[4-1. Construction of vehicle drive device ]

First, the configuration of the vehicle driving device according to the present embodiment will be described with reference to fig. 17. Fig. 17 is a block diagram showing a functional configuration of one phase in inverter 310 according to the present embodiment. Fig. 17 shows a functional configuration of u-phase in the inverter 310. The u-phase is described below, but v-phase and w-phase are the same.

The inverter 310 according to the present embodiment mainly includes relays 390 and 391, and is different from the inverter 210 according to embodiment 3 in that an output signal from the PWM drive circuit 260 is supplied to switching elements S1 and S4 via the relays 390 and 391. The following description will focus on the configuration of the inverter 310 according to the present embodiment, which is different from the inverter 210 according to embodiment 3. In this embodiment, the same or similar configuration as the inverter 210 according to embodiment 3 is given the same reference numerals as the inverter 210, and the description thereof is omitted or simplified.

As shown in fig. 17, the inverter 310 further includes relays 390 and 391 as compared to the inverter 210. The inverter 310 does not include the relay 290 for switching the on state of the step-down DC power supply 70 and the PWM driving circuit 260. In the present embodiment, the PWM driving circuit 260 receives power supply from the step-down DC power supply 70 without via the relays 390 and 391.

In the relay 390, one end is connected to the PWM driving circuit 260 (for example, a high-side terminal of the PWM driving circuit 260), and the other end is connected to the gate of the switching element S1, and it is selectively switched whether or not to supply the output signal from the PWM driving circuit 260 to the gate of the switching element S1.

The relay 390 has a switch 390a as a contact and a coil 390b as a primary winding. The relay 390 turns on or off the switch 390a by a magnetic force generated by flowing a current to the coil 390b. In the present embodiment, the relay 390 has a structure in which the AND circuit 253 outputs a simultaneous on detection signal AND supplies a current to the coil 390b, AND the switch 390a is turned off. The switch 390a is an example of a cut-off switch for cutting off the power supply from the PWM driving circuit 260 to the switching element S1.

The relay 390 connects the PWM driving circuit 260 and the gate of the switching element S1 when the vehicle driving device is driven normally or three-phase short-circuit. When the logic circuit, the substrate, or the like of the three-phase short-circuit switching circuit 250 fails and a signal for simultaneously turning on the switching elements of the upper and lower arms is output, the relay 390 releases (cuts off) the connection between the PWM driving circuit 260 and the gate of the switching element S1.

Accordingly, the relay 390 can turn off the switching element S1 when the switching element S1 is not normally operated by the logic circuit of the three-phase short-circuit switching circuit 250 based on the PWM signal from the microcontroller 240.

In the relay 391, one end is connected to the PWM driving circuit 260 (for example, a low-side output terminal of the PWM driving circuit 260), and the other end is connected to the gate of the switching element S4, and whether or not to supply the output signal from the PWM driving circuit 260 to the gate of the switching element S4 is selectively switched.

The relay 391 has a switch 391a as a contact and a coil 391b as a primary winding. The relay 391 turns on or off the switch 391a by a magnetic force generated by flowing a current to the coil 391b. In the present embodiment, the relay 391 has a structure in which a current supplied by outputting the simultaneous on detection signal from the AND circuit 253 flows to the coil 391b, AND the switch 391a is turned off. The switch 391a is an example of a cut-off switch for cutting off the power supply from the PWM driving circuit 260 to the switching element S4.

The relay 391 connects the PWM driving circuit 260 to the gate of the switching element S4 when the vehicle driving apparatus performs normal driving or three-phase short-circuit driving. When the logic circuit, the substrate, or the like of the three-phase short-circuit switching circuit 250 fails and a signal for simultaneously turning on the switching elements of the upper and lower arms is output, the relay 391 releases (cuts off) the connection between the PWM driving circuit 260 and the gate of the switching element S4.

Accordingly, when the switching element S4 is not normally operated by the logic circuit of the three-phase short-circuit switching circuit 250 based on the PWM signal from the microcontroller 240, the relay 391 can turn off the switching element S4.

One ends of the coils 390b AND 391b are electrically connected to the AND circuit 253. Therefore, when the AND circuit 253 outputs the simultaneous conduction detection signal, a current based on the signal flows to both the coils 390b AND 391 b. In other words, relays 390 and 391 are turned on simultaneously and turned off simultaneously. The on/off operation of the relays 390 and 391 can be said to be synchronous. Relays 390 and 391 are examples of cut-off circuits. The turning off of the relays 390 and 391 is an example of the turning off (cutting off) of the outputs of the PWM driving circuit 260 to the plurality of switching elements S1 to S6.

Accordingly, the relays 390 and 391 can suppress a short circuit between the positive and negative electrodes of the battery P1 due to the failure of the three-phase short-circuit switching circuit 250 when the vehicle drive device is driven normally or is driven by a three-phase short circuit. In addition, the failure of the three-phase short-circuit switching circuit 250 is due to, for example, at least 1 failure of the logic circuit or the like.

[4-2. Action of vehicle drive device ]

Next, the operation of the vehicle driving device will be described with reference to fig. 18. Fig. 18 is a flowchart showing an example of the operation of the vehicle driving device according to the present embodiment. Fig. 18 shows the operation of the inverter 310 in a state where normal driving or three-phase short-circuit driving is performed. In addition, in a state where normal driving or three-phase short-circuit driving is performed, the switches 390a and 391a are turned on. In other words, the output signal from the PWM driving circuit 260 is supplied to the gate of the switching element. The u-phase is described below, but v-phase and w-phase are the same. The operation of the inverter 310 when switching from the normal driving state to the three-phase short-circuit driving state is similar to that of fig. 12 of embodiment 3, and therefore, the description thereof is omitted.

As shown in fig. 18, when the AND circuit 253 detects a signal that the switching elements S1 AND S4 are simultaneously turned on in a state where the inverter 310 is normally driven or three-phase short-circuit driven (yes in S141), the AND circuit 253 outputs a signal for cutting the gate drive lines of the switching elements S1 AND S4 of the upper AND lower arms to the relays 390 AND 391 (S142). The operation of step S142 corresponds to outputting a signal for turning off the switching elements S1 and S4 of the upper and lower arms to the relays 390 and 391. The signal may be any signal that can turn off the relays 390 and 391. The signal is the simultaneous conduction detection signal. In the present embodiment, the AND circuit 253 outputs the signal to the microcontroller 240 in step S142, but the present invention is not limited to this. The AND circuit 253 outputs the signal to the microcontroller 240 as an example of the output detection result.

The relays 390 AND 391 are turned off when the signal is obtained from the AND circuit 253. Specifically, the relay 390 turns off the switch 390a by a current based on the signal flowing to the coil 390 b. The relay 391 turns off the switch 391a when a current based on the signal flows to the coil 391 b. The current values of the currents flowing to the coils 390b and 391b are, for example, the same.

Accordingly, the output signal from the PWM driving circuit 260 to the switching elements S1 and S4 is cut off on the path from the PWM driving circuit 260 to the switching elements S1 and S4. In other words, the gate voltage is not supplied from the PWM driving circuit 260 to the switching elements S1 and S4. In other words, the AND circuit 253 turns off the switching element S1 of the upper arm AND the switching element S4 of the lower arm by outputting the signals (S143).

Further, the microcontroller 240 may prohibit the output of the three-phase short-circuit instruction to the three-phase short-circuit switching circuit 250 when the signal is obtained from the AND circuit 253. In other words, the microcontroller 240 can perform control not to perform the three-phase short-circuit driving.

When this signal is obtained from the AND circuit 253, the microcontroller 240 notifies the upper ECU of a signal that the switching elements S1 AND S4 of the upper AND lower arms are simultaneously turned on (S144). This is the same processing as step S124 shown in fig. 13, and therefore the description is omitted.

In addition, when the AND circuit 253 does not detect a signal that the switching elements S1 AND S4 are simultaneously turned on in the normal driving or the three-phase short-circuit driving state (no in S141), the inverter 310 ends the process without performing the operation to turn off the switching elements S1 AND S4 of the upper AND lower arms. In other words, the inverter 310 continues the normal driving or the three-phase short-circuit driving state.

As described above, the control method of the vehicle driving device according to the present embodiment includes the 1st step and the 2 nd step, and in the 1st step, the signals for turning on the switching elements (for example, the switching elements S1 and S4) of the upper and lower arms simultaneously are detected, and in the 2 nd step, the switching elements of the upper and lower arms are turned off when the signals for turning on simultaneously are detected. The 2 nd step includes a step of cutting off the output signals from the PWM driving circuit 260 to the switching elements of the upper and lower arms.

Accordingly, in the case where the three-phase short-circuit switching circuit 250 fails and a signal is output to turn on the switching elements of the upper and lower arms simultaneously, the vehicle driving device can suppress the switching elements of the upper and lower arms from being turned on simultaneously, in other words, can suppress a short circuit between the positive and negative electrodes of the battery P1.

Embodiment 5

The inverter 410 according to the present embodiment will be described below with reference to fig. 19. Fig. 19 is a block diagram showing a functional configuration of one phase of an inverter 410 according to the present embodiment. Fig. 19 shows a functional configuration of u-phase in the inverter 410. The u-phase is described below, but v-phase and w-phase are the same. Note that, the same or similar structures as those of the embodiment or the modification of the embodiment are given the same reference numerals, and the description thereof may be omitted or simplified. The vehicle driving device according to the present embodiment includes, for example, an inverter 410 instead of the inverter 10 of the vehicle driving device 5 according to embodiment 1.

As shown in fig. 19, the inverter 410 has a step-down DC power supply 70, an overvoltage detection circuit 80, and a control circuit 430. The control circuit 430 includes a microcontroller 240, a PWM drive circuit 260, a three-phase short-circuit switching circuit 450, and a three-phase short-circuit drive circuit 460.

The power supply changeover switch 61 included in the three-phase short-circuit driving circuit 460 cuts off the gate output of the PWM driving circuit 260 by a signal from the NOT circuit 255 of the three-phase short-circuit switching circuit 450, and applies a voltage to the gate of the switching element S4 to S6 of the lower arm of the plurality of switching elements S1 to S6. In the power supply changeover switch 61, one end is connected to the step-down DC power supply 70, one end is connected to the PWM driving circuit 260, and the other end is connected to the gate of the switching element S4, whereby the power supply destination of the step-down DC power supply 70 can be selectively changed. The power supply changeover switch 61 connects the step-down DC power supply 70 and the PWM driving circuit 260 when the vehicle driving apparatus is normally driven. The power supply changeover switch 61 connects the step-down DC power supply 70 and the switching element S4 when the vehicle driving device performs three-phase short-circuit driving. The power supply changeover switch 61 is an example of the 1 st switch.

The three-phase short-circuit switching circuit 450 is connected to the microcontroller 240 and the PWM driving circuit 260, and outputs a signal according to the PWM signal from the microcontroller 240 and the three-phase short-circuit command to the PWM driving circuit 260. When the inverter 410 is abnormal, the three-phase short-circuit switching circuit 450 performs a three-phase short-circuit for the switching elements S4 to S6 of the lower arm among the plurality of switching elements S1 to S6 to suppress an overvoltage applied to the inverter 410. Specifically, when the inverter 410 is abnormal, the three-phase short-circuit switching circuit 450 outputs signals (driving signals) to the PWM driving circuit 260, which turn off the switching elements S1, S2, and S3 (switching elements of the upper arm) and turn on the switching elements S4, S5, and S6 (switching elements of the lower arm).

The three-phase short-circuit switching circuit 450 has an AND circuit 251, an OR circuit 252, a latch circuit 254, AND a NOT circuit 255. The three-phase short-circuit switching circuit 450 has a configuration in which the three-phase short-circuit switching circuit 250 according to embodiment 3 does not have the AND circuit 253.

In normal driving, for example, a high-level signal is output from the latch circuit 254, and in three-phase short-circuit driving, a low-level signal (active L in fig. 19) is output from the latch circuit 254.

The AND circuit 251 outputs a low-level signal based on the low-level signal from the latch circuit 254 at the time of three-phase short-circuit driving. The low-level signal is a signal for turning off the switching element S1.

The OR circuit 252 outputs a high-level signal based on the high-level signal from the NOT circuit 255 at the time of three-phase short-circuit driving. The high-level signal is a signal for turning on the switching element S4.

In the NOT circuit 255, an input terminal is connected to the latch circuit 254, an output terminal is connected to an input terminal of the OR circuit 252, the power supply changeover switch 61, and the insulating switch 63, and when a low-level signal is input from the latch circuit 254, a high-level signal is output. When a three-phase short-circuit signal or a three-phase short-circuit command is input to the latch circuit 254, a low-level signal for performing three-phase short-circuit driving is output from the latch circuit 254. The NOT circuit 255 outputs a high-level signal when a low-level signal is input.

The NOT circuit 255 outputs a high-level signal to the power supply changeover switch 61, the insulating switch 63, and the OR circuit 252 when three-phase short-circuit driving is performed. The high-level signal is output to the power supply changeover switch 61, and the connection of the power supply changeover switch 61 is switched, and the step-down DC power supply 70 is connected to the gate of the switching element S4, so that the inverter 410 can perform three-phase short-circuit driving. Further, a signal of a high level is output to the insulating switch 63, so that the insulating switch 63 is turned on, and a signal for causing the discharge circuit 64 to perform discharge is output. When the three-phase short-circuit driving is performed, the electric charge on the gate of the switching element S1 is discharged by the discharge circuit 64, and the gate and source potentials of the switching element S1 can be made the same, so that the inverter 410 can reliably turn off the switching element S1.

When the inverter 410 is abnormal, the three-phase short-circuit driving circuit 460 performs a three-phase short circuit for shorting the switching elements S4, S5, and S6 of the lower arm of the plurality of switching elements S1 to S6 together in order to suppress an overvoltage applied to the inverter 410. Specifically, when the inverter 410 is abnormal, the three-phase short-circuit driving circuit 460 turns off the switching elements S1, S2, S3 of the upper arm, and turns on the switching elements S4, S5, S6 of the lower arm. Accordingly, the induced voltage generated from the motor M1 can be made almost 0 (zero), so that the overvoltage of the three-phase bridge circuit 20 can be suppressed.

The three-phase short-circuit driving circuit 460 has a resistor R4 in addition to the configuration of the three-phase short-circuit driving circuit 60 according to embodiment 1. In the resistor R4, one terminal is connected to the discharge circuit 64, and the other terminal is connected to the gate of the switching element S1. In other words, the discharge circuit 64 and the gate of the switching element S1 are connected via the resistor element R4.

As described above, the vehicle driving device according to the present embodiment includes: the microcontroller 240 outputs a PWM (Pulse Width Modulation) signal, which is a pulse width modulation signal that controls an inverter 410 for driving a three-phase motor mounted on the electric vehicle 1, in which a plurality of switching elements S1 to S6 are connected in a three-phase bridge structure; a PWM driving circuit 260 for driving the plurality of switching elements S1 to S6 according to the PWM signal outputted from the microcontroller 240; a three-phase short-circuit driving circuit 460 that performs a three-phase short circuit in which the switching elements S4 to S6 of the lower arm among the plurality of switching elements S1 to S6 are short-circuited together when the inverter 410 is abnormal; and a three-phase short-circuit switching circuit 450 that outputs a signal for performing a three-phase short circuit, that is, a short circuit of the switching elements S4 to S6 of the lower arm among the plurality of switching elements S1 to S6 together, to the PWM driving circuit 260 when the inverter 410 is abnormal.

The three-phase short-circuit driving circuit 460 has a power supply changeover switch 61 and an insulating switch 63, the power supply changeover switch 61 cuts off the gate output of the PWM driving circuit 260 by a three-phase short-circuit signal or a three-phase short-circuit instruction, applies a voltage to the gates of the switching elements S4 to S6 of the lower arm, and the insulating switch 63 short-circuits between the gates and sources of the switching elements S1 to S3 of the upper arm in the plurality of switching elements S1 to S6 by the three-phase short-circuit signal or the three-phase short-circuit instruction.

The three-phase short-circuit switching circuit 450 is electrically connected between the microcontroller 240 and the PWM driving circuit 260, and outputs a PWM signal as a driving signal to the PWM driving circuit 260 in a normal operation, and outputs a driving signal to the PWM driving circuit 260, which turns on the switching elements S4 to S6 of the lower arm and turns off the switching elements S1 to S3 of the upper arm of the plurality of switching elements S1 to S6 when the three-phase short-circuit signal or the three-phase short-circuit command is input.

The following describes the execution of the three-phase short-circuit driving in the inverter 410 as described above. First, an example will be described in which three-phase short-circuit driving is performed when the operation of the three-phase short-circuit driving circuit 460 is normal. In this case, as described above, when the three-phase short-circuit driving is performed, the high-level signal is output from the NOT circuit 255 to the power supply switching switch 61, so that the connection of the power supply switching switch 61 is switched. Specifically, the state is switched from the state in which the step-down DC power supply 70 is connected to the PWM driving circuit 260 to the state in which the step-down DC power supply 70 is connected to the switching element S4. Thereby performing three-phase short circuit driving.

In this way, when the operation of the three-phase short-circuit driving circuit 460 is normal, the inverter 410 can perform three-phase short-circuit driving regardless of the signal input from the three-phase short-circuit switching circuit 450 to the PWM driving circuit 260.

Next, an example of three-phase short-circuit driving in the case where the operation of the three-phase short-circuit driving circuit 460 is abnormal will be described. For example, when the power supply changeover switch 61 fails and a high-level signal is input from the NOT circuit 255, the three-phase short-circuit driving circuit 460 may NOT be switched. Further, the failure of the power supply changeover switch 61 may be, for example, adhesion of a terminal on the step-down DC power supply 70 side of the power supply changeover switch 61 to a terminal on the PWM driving circuit 260 side.

In this case, a signal of a high level is output from the NOT circuit 255 to the power supply changeover switch 61 at the time of three-phase short-circuit driving, but since the power supply changeover switch 61 malfunctions, there is a possibility that the connection is NOT switched. In other words, at the time of three-phase short-circuit driving, it is possible to supply power from the step-down DC power supply 70 to the PWM driving circuit 260.

In the present embodiment, the inverter 410 includes a three-phase short-circuit switching circuit 450, and a signal for turning off the switching element S1 and turning on the switching element S4 is outputted from the three-phase short-circuit switching circuit 450 during three-phase short-circuit driving. Since the three-phase short-circuit switching circuit 450 supplies power to the PWM driving circuit 260 due to the failure of the power supply switching switch 61, the switching element S1 can be turned off and the switching element S4 can be turned on according to the signal from the three-phase short-circuit switching circuit 450.

When the operation of the three-phase short-circuit driving circuit 460 is abnormal, the inverter 410 can perform three-phase short-circuit driving based on a signal (driving signal) output from the three-phase short-circuit switching circuit 450 to the PWM driving circuit 260. Further, since the high-level signal is simultaneously output from the NOT circuit 255 to the power supply switching switch 61 and the OR circuit 252, even if the power supply switching switch 61 does NOT operate, a signal for performing three-phase short-circuiting can be immediately output from the three-phase short-circuit switching circuit 450.

Further, regardless of whether or NOT the operation of the three-phase short-circuit driving circuit 460 is normal, a high-level signal is output from the NOT circuit 255 to the insulating switch 63. Thus, the discharge circuit 64 can short-circuit the gate-source of the switching element S1 of the upper arm, regardless of whether or not the three-phase short-circuit driving circuit 460 is operating normally.

Embodiment 6

The inverter 510 according to the present embodiment is described below with reference to fig. 20. Fig. 20 is a block diagram showing a functional configuration of one phase in the inverter 510 according to the present embodiment. Fig. 20 shows a functional configuration of the u-phase in the inverter 510. The u-phase is described below, but v-phase and w-phase are the same.

The inverter 510 according to the present embodiment mainly differs from the inverter 410 according to embodiment 5 in that the three-phase short-circuit switching circuit 250 includes an AND circuit 253, AND the three-phase short-circuit driving circuit 560 includes a cut-off switch 590. The inverter 510 according to the present embodiment will be described mainly with respect to differences from the inverter 410 according to embodiment 5. In this embodiment, the same or similar configuration as the inverter 410 according to embodiment 5 is given the same reference numerals as the inverter 410, and the description thereof is omitted or simplified.

As shown in fig. 20, the inverter 510 has a step-down DC power supply 70, an overvoltage detection circuit 80, and a control circuit 530. Further, the control circuit 530 includes: microcontroller 240, three-phase short circuit switching circuit 250, PWM drive circuit 260, three-phase short circuit drive circuit 560.

The three-phase short-circuit switching circuit 250 has an AND circuit 253 in addition to the three-phase short-circuit switching circuit 450 according to embodiment 5. The configuration of the three-phase short-circuit switching circuit 250 according to the present embodiment is the same as the three-phase short-circuit switching circuit 250 according to embodiment 3.

In the AND circuit 253, an output terminal is connected to the microcontroller 240 AND the cut-off switch 590. The AND circuit 253 outputs a simultaneous conduction detection signal (for example, a high-level signal) showing that the switching elements S1 AND S4 are simultaneously turned on to the microcontroller 240 AND the cut-off switch 590 when a high-level drive signal is input from both the AND circuit 251 AND the OR circuit 252, for example. The AND circuit 253 does not output the simultaneous conduction detection signal when a low-level drive signal is input from one OR both of the AND circuit 251 AND the OR circuit 252, for example. The output terminal of the AND circuit 253 may be connected to at least the cut-off switch 590.

The three-phase short-circuit driving circuit 560 has a cut-off switch 590 in addition to the configuration of the three-phase short-circuit driving circuit 460 according to embodiment 5.

The cut-off switch 590 is a switch that switches whether or not the electric power supplied from the step-down DC power supply 70 via the power supply changeover switch 61 is supplied to the PWM driving circuit 260. The cut-off switch 590 is electrically connected between the power supply changeover switch 61 and the PWM driving circuit 260. In the cut-off switch 590, for example, one end is connected to one of the other ends of the power supply changeover switch 61, the other end is connected to the PWM driving circuit 260, AND the on/off is switched by a signal from the AND circuit 253. Specifically, the cut-off switch 590 is turned off when the simultaneous on detection signal is output from the AND circuit 253. In other words, when the AND circuit 253 detects simultaneous conduction, the off switch 590 stops the supply of power from the step-down DC power supply 70 to the PWM driving circuit 260. The off switch 590 is turned on when the AND circuit 253 does not output the simultaneous conduction detection signal. In other words, when the AND circuit 253 does not detect simultaneous conduction, the switch 590 is turned off, AND power is supplied from the step-down DC power supply 70 to the PWM driving circuit 260.

The cut-off switch 590 is implemented by, for example, a semiconductor switch, an electromagnetic on-off switch, or the like, but is not limited thereto. The cut-off switch 590 is an example of a cut-off circuit.

As described above, the vehicle driving device according to the present embodiment includes: the microcontroller 240 outputs a PWM (Pulse Width Modulation) signal, which is a pulse width modulation signal for controlling an inverter 510 for driving a three-phase motor mounted on the electric vehicle 1, in which a plurality of switching elements S1 to S6 are connected in a three-phase bridge structure; a PWM driving circuit 260 for driving the plurality of switching elements S1 to S6 according to the PWM signal outputted from the microcontroller 240; a three-phase short-circuit driving circuit 560 that performs a three-phase short circuit when the inverter 510 is abnormal, the three-phase short circuit being a short circuit of all of the switching elements S4 to S6 of the lower arm among the plurality of switching elements S1 to S6; and a three-phase short-circuit switching circuit 250 that outputs a signal for performing a three-phase short circuit, that is, a short circuit of the switching elements S4 to S6 of the lower arm among the plurality of switching elements S1 to S6 together, to the PWM driving circuit 260 when the inverter 510 is abnormal.

The three-phase short-circuit driving circuit 560 has a power supply changeover switch 61 and an insulating switch 63, the power supply changeover switch 61 cuts off the gate output of the PWM driving circuit 260 by a three-phase short-circuit signal or a three-phase short-circuit instruction and applies a voltage to the gates of the switching elements S4 to S6 of the lower arm, and the insulating switch 63 short-circuits between the gates and sources of the switching elements S1 to S3 of the upper arm in the plurality of switching elements S1 to S6 by the three-phase short-circuit signal or the three-phase short-circuit instruction.

The three-phase short-circuit switching circuit 250 is electrically connected between the microcontroller 240 and the PWM driving circuit 260, and outputs a PWM signal as a driving signal to the PWM driving circuit 260 in a normal operation, and outputs a driving signal to the PWM driving circuit 260, which turns on the switching elements S4 to S6 of the lower arm and turns off the switching elements S1 to S3 of the upper arm of the plurality of switching elements S1 to S6 when the three-phase short-circuit signal or the three-phase short-circuit command is input.

The three-phase short-circuit switching circuit 250 further includes an AND circuit 253 (an example of a monitor circuit), AND an upper arm drive signal for driving the switching elements S1 to S3 of the upper arm AND a lower arm drive signal for driving the switching elements S4 to S6 of the lower arm are input to the AND circuit 253. The AND circuit 253, when detecting that the upper arm drive signal AND the lower arm drive signal are signals for turning on both the switching element of the upper arm AND the switching element of the lower arm, causes the cut-off switch 590 (an example of a cut-off circuit) that cuts off the output of the PWM drive circuit 260 to the plurality of switching elements S1 to S6 to operate as follows. The cut-off switch 590 is electrically connected between the power supply changeover switch 61 and the PWM driving circuit 260.

The operation when the inverter 510 detects simultaneous conduction as described above will be described. In the description, the simultaneous conduction is detected due to a failure of the logic circuit (for example, a failure of at least one of the AND circuit 251 AND the OR circuit 252), but the simultaneous conduction may be detected due to a failure of the microcontroller 240 OR the like.

The AND circuit 253 outputs a simultaneous conduction detection signal to the cut-off switch 590 when detecting simultaneous conduction in a state (normal state) in which the three phases are not shorted, AND turns off the cut-off switch 590. In other words, the AND circuit 253 forcibly stops the output from the PWM driving circuit 260 to the switching elements S1 AND S4, thereby suppressing the switching elements S1 AND S4 from being simultaneously turned on.

In this case, since the switching elements S1 and S4 are turned off and the motor M1 continues to rotate when the electric vehicle 1 is traveling, the overvoltage is applied to the three-phase bridge circuit 20 by regenerative power or the like. In order to suppress the overvoltage, it is conceivable to perform three-phase short-circuit driving, but since the cutoff switch 590 is turned off, the PWM driving circuit 260 cannot perform three-phase short-circuit driving.

Then, when the microcontroller 240 obtains the simultaneous on detection signal from the AND circuit 253, the three-phase short-circuit instruction is output to the latch circuit 254. Accordingly, since the connection of the power supply changeover switch 61 can be switched, even after the simultaneous conduction is detected (after the operation of the PWM drive circuit 260 is stopped), the three-phase short-circuit drive circuit 560 can perform the three-phase short-circuit drive. In other words, the microcontroller 240 performs three-phase short-circuit driving without using the logic circuit of the failed three-phase short-circuit switching circuit 250.

In this case, since the microcontroller 240 outputs a three-phase short-circuit command and a high-level signal is input to the insulating switch 63, the insulating switch 63 can short-circuit the gate-source of the switching element S1 via the discharging circuit 64.

When the simultaneous on detection signal is output in a state where the three-phase short circuit is required, for example, the microcontroller 240 immediately outputs a three-phase short circuit command, and thus the three-phase short circuit can be executed by the three-phase short circuit driving circuit 560.

The microcontroller 240 is not limited to performing the three-phase short-circuit driving after detecting the simultaneous conduction. The microcontroller 240 may not perform the three-phase short-circuit driving in a case where the overvoltage is difficult to generate, for example, when the electric vehicle 1 is stopped or running at a low speed.

Further, when the simultaneous conduction is detected, the switching elements S1 and S4 are turned off, and then the overvoltage is detected by the overvoltage detection circuit 80, so that the three-phase short-circuit driving can be performed after the simultaneous conduction is detected.

The above-described inverter 510 is similar to the inverter 410 according to embodiment 5 in that the three-phase short-circuit driving is performed.

The operation of the power supply changeover switch 61 when not switching is the same as that of the inverter 410 according to embodiment 5.

(Other embodiments)

The vehicle driving device 5 and the like according to 1 or more aspects are described above according to the embodiments, but the present disclosure is not limited to these embodiments. Various modifications, which are intended by those skilled in the art, are implemented in the present embodiment or in the form of a combination of the constituent elements of the different embodiments within the scope not exceeding the spirit of the present disclosure, and are also included in the scope of the present disclosure.

For example, in the embodiment and the like, when the microcontroller 40 obtains the three-phase short-circuit signal from the overvoltage detection circuit 80, the output of the PWM signal to the PWM drive circuit 50 may be stopped.

Further, in the embodiment and the like, the microcontroller 40 may output a signal showing that the three-phase short-circuit signal is obtained to the ECU of the electric vehicle 1 when the three-phase short-circuit signal is obtained from the overvoltage detection circuit 80.

In the modification of embodiment 1, the failure notification circuit 91 is described as a monitor clock circuit, but the present invention is not limited to this, and the microcontroller 40 may be a dual-core processor (dual-core processor) to determine an abnormality by a self-diagnosis function, for example. Specifically, as a self-diagnosis function, the presence or absence of an abnormality is determined by a double-core lockstep method. In the dual-core lockstep method, the dual-core processor causes 2 processor cores to execute the same processing, and determines that there is an exception when the processing results are inconsistent. In this case, the failure notification signal described in the modification of embodiment 1 may be used as an abnormal output signal of the dual-core processor. In addition to the above, abnormality of the clock frequency or the like may be detected as a self-diagnosis function.

In embodiment 2, the inverter 110 is not limited to the configuration having the relays 165 and 166 on the output side of the PWM drive circuit 50, as long as the PWM drive circuit 50 and the switching elements S1 to S6 can be insulated from each other when the three-phase short-circuit operation is performed. The inverter 110 may have, for example, a photocoupling element and a logic circuit on the output side of the PWM drive circuit 50.

For example, in the embodiment and the like, the microcontroller 240 may stop outputting the PWM signal to the three-phase short-circuit switching circuit 250 when the three-phase short-circuit signal is obtained from the overvoltage detection circuit 80.

Further, in the embodiment and the like, the microcontroller 240 may output a signal showing that the three-phase short-circuit signal is obtained to the ECU of the electric vehicle 1 when the three-phase short-circuit signal is obtained from the overvoltage detection circuit 80.

In the modification of embodiment 3, the failure notification circuit 301 is described as a monitor clock circuit, but the present invention is not limited to this, and the microcontroller 240 may be a dual-core processor, for example, and may determine an abnormality by a self-diagnosis function. Specifically, as a self-diagnosis function, the presence or absence of abnormality is determined by a double-core lockstep method. In the dual-core lockstep method, the dual-core processor causes 2 processor cores to execute the same processing, and determines that there is an exception when the processing results are inconsistent. In this case, the failure notification signal described in the modification of embodiment 3 may be used as an abnormal output signal of the dual-core processor. In addition, besides the above, abnormality of the clock frequency or the like may be detected as a self-diagnosis function.

In embodiment 3, the inverter 210 is not limited to the one having the relay 290, as long as the connection between the PWM driving circuit 260 AND the step-down DC power supply 70 can be cut off by the simultaneous on detection signal from the AND circuit 253. Inverter 210 may have, for example, a photo-coupling element and logic circuit electrically connected between PWM drive circuit 260 and buck DC power supply 70.

In embodiment 4, the inverter 310 is not limited to the case where the relays 390 and 391 are provided on the output side of the PWM drive circuit 260, as long as the PWM drive circuit 260 can be insulated from the switching elements S1 to S6 at the time of three-phase short-circuit driving. The inverter 310 may have a photoelectric coupling element and a logic circuit on the output side of the PWM driving circuit 260, for example.

In the above embodiment and the like, the three-phase short-circuit switching circuit 250 is described as having a logic circuit for outputting a drive signal to the PWM drive circuit 260, but the present invention is not limited thereto. The three-phase short-circuit switching circuit 250 may have a component other than a logic circuit as long as it can output a drive signal to the PWM drive circuit 260. In this case, the AND circuit 253 detects that a component or the like included in the three-phase short-circuit switching circuit 250 has failed.

The logic circuits shown by way of example in the above embodiments and the like are examples, and if other logic circuits or a combination of these can realize the same function, logic circuits other than the logic circuits shown by way of example may be used.

The present disclosure is useful as a vehicle driving device that drives an electric vehicle.

Symbol description

1. Electric vehicle

2. Driving wheel

3. Power transmission mechanism

5. Vehicle driving device

10, 10A,110, 210a,310, 410, 510 inverter

20. Three-phase bridge circuit

30, 230, 430, 530 Control circuits

40, 240 Microcontroller (microcontroller)

50, 260 PWM drive circuit

60, 160, 460, 560 Three-phase short circuit driving circuit

61, 161 Power supply change-over switch

62. Latch circuit

63. Insulated switch

64. Discharge circuit

70. Step-down DC power supply

71 DC/DC converter

80. Overvoltage detection circuit

90. Abnormality detection circuit

91. Failure notification circuit

92 NOT circuit

165, 166 Relay

165A,166a,290a,390a switch

165B,166b,290b,390b coil

250, 450 Three-phase short-circuit switching circuit

251, 253 AND circuit

252 OR circuit

254. Latch circuit

255, 302 NOT circuit

290, 390, 391 Relay (cut-off circuit)

300. Abnormality detection circuit

301. Failure notification circuit

590. Cut-off switch (cut-off circuit)

C1 Smoothing capacitor

CSu, CSv, CSw current sensor

Lg grounding wire

Lp power line

M1 permanent magnet motor

P1, P2 battery

R1, R2, R3, R4 resistor element

RS rotary position sensor

S1, S2, S3, S4, S5, S6 switching element

Vg, vp voltage

Claims

1. A driving device for a vehicle is provided,

The vehicle driving device includes:

A microcontroller that outputs a PWM signal that is a pulse width modulation signal for controlling an inverter for driving a three-phase motor mounted on a vehicle, the inverter having a plurality of switching elements connected in a three-phase bridge configuration;

A PWM driving circuit that drives the plurality of switching elements according to the PWM signal output from the microcontroller; and

A three-phase short-circuit driving circuit for performing a three-phase short circuit when the inverter is abnormal, wherein the three-phase short circuit means that the switching elements of the lower arm of the plurality of switching elements are short-circuited together,

The three-phase short circuit driving circuit has a1 st switch and a2 nd switch,

The 1 st switch cuts off a gate output of the PWM driving circuit by the command signal of the three-phase short circuit and applies a voltage to the gate of the switching element of the lower arm,

And the 2 nd switch is used for shorting the grid sources of the switching elements of the upper arm in the switching elements through the command signal of the three-phase short circuit.

2. The vehicle driving device according to claim 1,

The power supply of the PWM driving circuit is a power supply based on at least one of a1 st dc battery and a2 nd dc battery, wherein the 1 st dc battery is a battery for driving the three-phase motor, and the 2 nd dc battery is a battery for supplying electric power to an electric component of the vehicle, and has a voltage lower than that of the 1 st dc battery.

3. The vehicle driving device according to claim 1 or 2,

The abnormality of the inverter includes an abnormality of the microcontroller.

4. The vehicle driving device according to claim 3,

The vehicle driving device further includes an abnormality detection circuit for detecting an abnormality of the microcontroller,

And the abnormality detection circuit outputs the command signal of the three-phase short circuit to the three-phase short circuit driving circuit when detecting abnormality of the microcontroller.

5. The vehicle driving device according to claim 2,

The abnormality of the inverter includes an overvoltage state in which the voltage of the 1 st direct current battery exceeds a predetermined voltage.

6. The vehicle driving device according to claim 5,

The vehicle driving device further includes an overvoltage detection circuit for detecting the overvoltage state,

The overvoltage detection circuit is electrically connected to the 1 st direct current battery connected to the inverter, and outputs the command signal for the three-phase short circuit to the three-phase short circuit driving circuit when the overvoltage state is detected.

7. The vehicle driving device according to any one of claim 1, 2, 4 to 6,

The vehicle driving device further includes a latch circuit that holds the command signal of the three-phase short circuit,

The output of the latch circuit is input to the 1 st switch and the 2 nd switch.

8. The vehicle driving device according to any one of claim 1, 2, 4 to 6,

The vehicle driving device further includes a semiconductor switch connected to the 2 nd switch and the switching element of the upper arm,

The 2 nd switch is a photoelectric coupling element, the command signal for the three-phase short circuit is input to the photoelectric coupling element, and the semiconductor switch is turned on to short-circuit between the gate and the source of the switching element of the upper arm.

9. The vehicle driving device according to any one of claim 1, 2, 4 to 6,

The 2 nd switch has a relay, and the command signal for the three-phase short circuit is inputted, and the relay is turned on, thereby short-circuiting the gate-source electrodes of the switching elements of the upper arm.

10. The vehicle driving device according to claim 1,

The vehicle driving device further includes a three-phase short-circuit switching circuit that outputs a signal for performing a three-phase short circuit to the PWM driving circuit when the inverter is abnormal, the three-phase short circuit being a short circuit of switching elements of a lower arm among the plurality of switching elements together,

The three-phase short-circuit switching circuit is electrically connected between the microcontroller and the PWM driving circuit, outputs the PWM signal as a driving signal to the PWM driving circuit in a normal operation, and outputs the driving signal for turning on the switching element of the lower arm and turning off the switching element of the upper arm of the plurality of switching elements to the PWM driving circuit in a case where the command signal for the three-phase short-circuit is inputted,

When the 1 st switch does not perform an operation of cutting off the gate output of the PWM driving circuit by the command signal for the three-phase short circuit, the PWM driving circuit performs gate output based on the driving signal for turning on the switching element of the lower arm and turning off the switching element of the upper arm.

11. The vehicle driving device according to claim 10,

The three-phase short-circuit switching circuit includes a logic circuit that outputs the driving signal to the PWM driving circuit.

12. The vehicle driving device according to claim 10 or 11,

The abnormality of the inverter includes an abnormality of the microcontroller.

13. The vehicle driving device according to claim 12,

The abnormality detection circuit outputs the command signal for the three-phase short circuit to the three-phase short circuit switching circuit when abnormality of the microcontroller is detected.

14. The vehicle driving device according to any one of claim 10, 11, 13,

The abnormality of the inverter includes an overvoltage state in which a voltage of a power supply for driving the three-phase motor exceeds a prescribed voltage.

15. The vehicle driving device according to claim 14,

The overvoltage detection circuit is electrically connected to the power supply connected to the inverter, and outputs the command signal for the three-phase short circuit to the three-phase short circuit switching circuit when the overvoltage state is detected.

16. The vehicle driving device according to any one of claim 10, 11, 13, 15,

The three-phase short-circuit switching circuit further has a latch circuit that holds the command signal of the three-phase short circuit.

17. The vehicle driving device according to any one of claim 10, 11, 13, 15,

The drive signals include an upper arm drive signal that drives a switching element of an upper arm of the plurality of switching elements and a lower arm drive signal that drives a switching element of the lower arm,

The three-phase short-circuit switching circuit further has a monitor circuit to which the upper arm drive signal and the lower arm drive signal are input,

The monitor circuit causes a shut-off circuit to perform an operation of shutting off outputs of the PWM drive circuit to the plurality of switching elements when detecting that the upper arm drive signal and the lower arm drive signal are signals that turn on both the switching element of the upper arm and the switching element of the lower arm.

18. The vehicle driving device according to claim 17,

The monitoring circuit outputs the detection result to the microcontroller,

The microcontroller prohibits output of the command signal of the three-phase short circuit and outputs a signal for limiting the rotational speed of the three-phase motor when the detection result is obtained.

19. The vehicle driving device according to claim 17,

When detecting that the upper arm drive signal and the lower arm drive signal are signals for turning on the switching elements of the upper arm and the switching elements of the lower arm simultaneously, the shut-off circuit turns off the outputs from the PWM drive circuit to the plurality of switching elements.

20. The vehicle driving device according to claim 17,

When detecting that the upper arm drive signal and the lower arm drive signal are signals for simultaneously turning on the switching element of the upper arm and the switching element of the lower arm, the cut-off circuit cuts off power supply to the PWM drive circuit.

21. The vehicle driving device according to claim 20,

The cut-off circuit is electrically connected between the 1 st switch and the PWM driving circuit.