CN113306544A

CN113306544A - Inverter circuit, inverter control device, and vehicle drive device

Info

Publication number: CN113306544A
Application number: CN202110210180.6A
Authority: CN
Inventors: 中田雄飞; 小池上贵; 三本松功; 向山浩司
Original assignee: Nidec Corp; Nidec Elesys Corp
Current assignee: Nidec Corp; Nidec Elesys Corp
Priority date: 2020-02-26
Filing date: 2021-02-25
Publication date: 2021-08-27
Anticipated expiration: 2041-02-25
Also published as: CN113306544B

Abstract

The invention provides an inverter circuit, an inverter control device and a vehicle drive device. An inverter circuit that drives an electric motor as a drive source of a vehicle, the inverter circuit comprising: a parking lock instruction detection unit that detects a parking lock instruction that suppresses rotation of a drive wheel of the vehicle; and an energization stop unit that stops a drive current to the electric motor when the parking lock instruction is detected. Alternatively, an inverter circuit that drives an electric motor as a drive source of a vehicle includes: a parking lock instruction detection unit that detects a parking lock instruction that suppresses rotation of a drive wheel of the vehicle; a rotation angle detection unit that detects a rotation angle of a rotor of the electric motor; and a control unit that controls the electric motor so that the rotor rotation angle is equal to or less than a predetermined value when the parking lock instruction is detected.

Description

Inverter circuit, inverter control device, and vehicle drive device

Technical Field

The present disclosure relates to an inverter circuit, an inverter control device, and a vehicle drive device that supply drive power to a motor mounted on a vehicle or the like.

Background

In order to increase the height of vehicles such as electric vehicles and hybrid vehicles, in which a motor is used as a driving source, an inverter for supplying electric power to the motor and a control circuit thereof are required to have higher functions. In these vehicles, an Electronic Control Unit (ECU) determines a traveling state of the vehicle, a driving operation state of the driver, and the like based on detection signals from various sensors and signals from an in-vehicle device.

In general, a vehicle is provided with a parking lock mechanism that prevents rotation of an axle when the vehicle is parked. In an electric vehicle or the like, a parking lock is performed by engaging a lock pin with a gear or the like that rotates together with a tire to mechanically fix the tire and stop the vehicle.

Patent document 1 discloses a parking lock control device that controls an inverter to: in a vehicle, a parking gear of a parking lock mechanism is engaged with a pawl by adjusting a stop position of a tooth groove of the parking gear, and the parking gear is locked to mechanically fix an output shaft of an electric motor, thereby preventing the vehicle from slipping down after a parking position is selected.

Patent document 1: japanese laid-open patent publication No. 2018-176832

In an electric vehicle or the like having a parking lock control device mounted thereon as described in japanese patent application laid-open No. 2018-176832 and the like, since the current is supplied to the motor in accordance with a command corresponding to the operation of the accelerator pedal or the like by the driver, the motor cannot be rotated even if the current is supplied to the motor when the pedal is depressed during the parking lock.

At this time, since the rotation signal from the motor does not arrive, the upper control unit of the inverter performs control so that more electric power is supplied to rotate the motor. As a result, a large current flows through the motor during the parking lock, and problems such as a temperature increase of the motor, a temperature increase of the inverter circuit, and power consumption occur.

In addition, in an electric vehicle or the like having a parking lock control device mounted thereon as described in japanese laid-open patent publication No. 2018-176832 and the like, there is a problem that the vehicle cannot be stopped when, for example, the parking lock mechanism is not operated due to a failure or the like and the drive wheels cannot be mechanically fixed.

In such a case, there is also a problem that: in order to maintain the stopped state of the vehicle, the driver must operate a brake pedal or the like to cope with the shift to the parking lock, which increases the burden on the driver.

Disclosure of Invention

In view of the above problems, it is an object of the present disclosure to provide an inverter circuit that can avoid energization of a motor even when an accelerator pedal is operated during parking lock of an electric vehicle or the like. In view of the above problems, it is an object of the present disclosure to provide an inverter circuit that can maintain a stopped state of a vehicle even when a parking lock mechanism of an electric vehicle or the like is not operated.

As one means for achieving the above object and solving the above problems, the following configuration is provided. That is, a first aspect of an exemplary first embodiment of the present disclosure is an inverter circuit that drives an electric motor as a drive source of a vehicle, the inverter circuit including: a parking lock instruction detection unit that detects a parking lock instruction that suppresses rotation of a drive wheel of the vehicle; and an energization stop unit that stops a drive current to the electric motor when the parking lock instruction is detected.

A second aspect of the exemplary first embodiment of the present disclosure is an inverter control device for driving an electric motor, the inverter control device driving and controlling the electric motor by the inverter circuit of the first aspect of the exemplary first embodiment.

A third aspect of the exemplary first embodiment of the present disclosure is a vehicle driving device including the inverter control device of the second aspect of the exemplary first embodiment.

As one means for achieving the above object and solving the above problems, the following configuration is provided. That is, a first invention of an exemplary second embodiment of the present disclosure is an inverter circuit that drives an electric motor as a drive source of a vehicle, the inverter circuit including: a parking lock instruction detection unit that detects a parking lock instruction that suppresses rotation of a drive wheel of the vehicle; a rotation angle detection unit that detects a rotation angle of a rotor of the electric motor; and a control unit that controls the electric motor so that the rotor rotation angle is equal to or less than a predetermined value when the parking lock instruction is detected.

A second aspect of the exemplary second embodiment of the present disclosure is an inverter control device for driving an electric motor, the inverter control device being characterized in that the inverter circuit of the first aspect of the exemplary second embodiment of the present disclosure controls the electric motor.

A third aspect of the exemplary second embodiment of the present disclosure is a vehicle driving device including the inverter control device according to the second aspect of the exemplary second embodiment of the present disclosure.

According to one aspect of the present disclosure, even when the accelerator is operated during parking lock of an electric vehicle or the like, power is supplied to the motor as a drive source, and thus, temperature rise of the inverter circuit and the motor can be suppressed to avoid a failure, and power consumption of the battery can be suppressed.

Further, in the inverter control device, power consumption of the battery can be suppressed.

Further, in the vehicle driving device, power consumption of the battery can be suppressed.

According to one aspect of the present disclosure, the redundancy of the parking lock function can be improved in the vehicle by implementing the parking lock function by the motor control based on the inverter circuit, and the stopped state of the vehicle can be maintained even when the mechanical parking lock function is not operated.

Further, in the inverter control device, even when the mechanical parking lock function is not operated, the stopped state of the vehicle can be maintained.

Further, in the vehicle driving device, even when the mechanical parking lock function is not operated, the stopped state of the vehicle can be maintained.

The above and other features, elements, steps, features and advantages of the present invention will be more clearly understood from the following detailed description of preferred embodiments of the present invention taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a block diagram showing the overall configuration of a vehicle mounted with an inverter circuit according to a first embodiment of the present disclosure.

Fig. 2 is a block diagram showing the overall structure of a vehicle mounted with an inverter circuit according to a second embodiment of the present disclosure.

Fig. 3 is a diagram showing a part of the structure of a parking lock mechanism that locks the drive wheels of the vehicle.

Fig. 4 is a flowchart showing the processing procedure of the locking action and the lock release action of the parking lock function based on the inverter circuit of the first embodiment.

Fig. 5 is a flowchart showing the processing procedure of the locking action and the lock release action of the parking lock function based on the inverter circuit of the second embodiment.

Detailed Description

< first embodiment >

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Fig. 1 is a block diagram showing an overall configuration of a vehicle such as an electric vehicle on which an inverter circuit according to a first embodiment of the present disclosure is mounted.

In fig. 1, a vehicle 1 has the following parts: an Electronic Control Unit (ECU) 3 as a motor Control device; a Vehicle Control Unit (VCU) 2 as a higher-level Control Unit of the ECU 3; a Motor Control Unit (MCU) 9 that drives an electric Motor 15 as a drive source of the vehicle 1 in accordance with a Control signal from the ECU 3; a transmission 11 coupled to an electric motor 15 and transmitting a rotational driving force of the electric motor 15 to

wheels

13a and 13 b; and a parking lock mechanism 12 that is incorporated in the transmission 11 and locks the

wheels

13a, 13b against rotation. As shown by the two-dot chain line in fig. 1, the electronic control unit 3 and the motor control unit 9 may be integrated into the motor control device 6.

The vehicle 1 is, for example, an Electric Vehicle (EV) and has a battery BT that supplies a driving power source to an electric motor 15 as a power source.

The VCU 2 as the upper controller outputs, for example, a torque command value (torque control command), brake information, shift information corresponding to the driver's operation of the shift lever 5, and the like to the ECU 3.

While the vehicle 1 is running, the VCU 2 switches between torque control in which a target torque corresponding to the actual driving torque of the electric motor 15 is calculated and control is performed so that the torque of the electric motor 15 follows the torque command value, and speed control in which the actual rotational speed of the electric motor 15 is controlled (maintained) so as to be the target rotational speed.

When the driver of the vehicle 1 operates the accelerator pedal 21, an accelerator opening sensor (not shown) detects an operation amount (accelerator opening). The VCU 2 outputs a signal for controlling acceleration, deceleration, and the like of the vehicle 1 to the ECU 3 based on the accelerator opening information from the accelerator opening sensor.

When the brake pedal 23 is operated, the VCU 2 transmits a signal corresponding to the amount of brake operation from a brake stroke sensor, not shown, to the brake control unit 25 via the ECU 3. The brake control unit 25 controls a brake mechanism 27 including a brake pad, a hydraulic mechanism, and the like to stop the vehicle 1.

In addition, the braking control may also include regenerative braking control in which a braking force based on the amount of regeneration of the electric motor 15 is generated.

The ECU 3 has the following parts: a control unit (CPU)8, which is constituted by a microcomputer, for example, and performs vector control such as determining a command value of a current vector from a torque command value corresponding to an accelerator operation amount from the VCU 2, and is responsible for controlling the entire ECU 3; and a PWM signal generation unit 19 that generates a Pulse Width Modulation (PWM) signal in accordance with a voltage command value from the CPU 8. The voltage command value can be obtained by calculation using a known vector control technique.

In this way, the ECU 3 transmits output signals corresponding to an acceleration request, a deceleration request, and a stop request for the vehicle 1 to the MCU 9 to drive and control the electric motor 15. Therefore, the ECU 3 has a read-only memory (ROM)4 in which a drive control program and the like of the electric motor 15 are stored in advance.

The predriver unit 7 of the MCU 9 increases and decreases the duty ratio of the PWM control signal in accordance with the pulse width modulation signal from the PWM signal generation unit 19, thereby generating an on/off control signal (also referred to as a motor command signal or a gate drive signal) for the semiconductor switching elements constituting the motor drive unit 18 of the inverter circuit 10.

The external battery BT supplies a power source for driving the motor to the plurality of semiconductor switching elements in the motor driving unit 18 that supply a driving current to the electric motor 15. The Semiconductor switching element is also called a power element, and for example, a switching element such as a MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor) is used.

The inverter circuit 10 includes a parking lock signal detection unit 14, an energization stop unit 16, and the like, which will be described later, in addition to the motor drive unit 18.

The electric motor 15 is, for example, a three-phase brushless DC motor, and semiconductor switching elements of the motor drive unit 18 constituting the inverter circuit 10 of three phases (U-phase, V-phase, W-phase) correspond to the electric motor 15. The electric motor 15 performs a power running operation as an electric motor for performing rotational driving and a regenerative operation in which the rotor receives rotational energy from a driving wheel or the like and operates as a generator.

Fig. 3 is a diagram showing a part of the configuration of the parking lock mechanism 12 that locks the drive wheels of the vehicle 1. As shown in fig. 2, the parking lock mechanism 12 includes a parking lever 33, a parking column 34, a parking gear 32 having teeth arranged at regular intervals in the circumferential direction, and the like. The parking lever 33 is formed in a substantially L-shape, one end of which is attached to a brake plate (not shown) that moves the parking lever 33 in the axial direction, and the other end of which is provided with a parking cam (cone) 33a that abuts against the parking column 34.

The parking column 34 is pushed up by the operation of the conical parking cam 33a in the direction a in the drawing, and is rotated about the support pin 35. The parking column 34 is provided with a pawl portion 34 a. That is, the parking cam 33a is pressed in the a direction, and the parking column 34 is pushed up in the B direction in the figure.

When the claw portion 34a of the parking column 34 is lifted up to a position of meshing with the recessed portion formed between the adjacent teeth in the gear-shaped parking gear 32, the parking gear 32 meshes with the parking column 34. As a result, the parking lock is performed that mechanically prevents the rotation of the

drive wheels

13a and 13b that rotate in conjunction with the parking gear 32.

On the other hand, by moving the parking lever 33 and the conical parking cam 33a in the opposite direction (C direction in the figure), the parking column 34 is lowered in the D direction in the figure, and is rotated about the support pin 35. Thereby, the claw portion 34a of the parking column 34 is disengaged from the recessed portion of the parking gear 32, and the locked state is released in the parking lock mechanism 12.

Next, a parking lock operation by the inverter circuit according to the present embodiment will be described. Fig. 4 is a flowchart showing the processing procedure of the locking operation and the unlocking operation of the parking lock function by the inverter circuit according to the present embodiment.

When the driver of the vehicle 1 intends to lock the drive wheels and suppress the movement of the vehicle, the driver operates the shift lever 5 to the parking position P or presses a parking switch, not shown. In response to such an operation, the VCU 2 outputs a parking lock instruction signal (a signal to operate the parking lock function) to the ECU 3.

Therefore, when the parking lock signal detection unit 14 provided in the inverter circuit 10 in the MCU 9 detects the parking lock instruction signal transmitted from the VCU 2 via the ECU 3 in step S11 of fig. 4, it confirms whether or not the electric motor 15 is stopped in step S13.

When the electric motor 15 is not stopped, the MCU 9 activates the energization stopping unit 16 to stop the supply of the power from the inverter circuit 10 to the electric motor 15 in step S15. At the same time, the VCU 2 outputs a signal requesting a locking operation to the parking lock mechanism 12 so that the drive wheels (

wheels

13a, 13b) of the vehicle 1 cannot mechanically rotate.

Since the switching control (torque output) in the inverter circuit 10 is not performed by the energization stop processing in step S15, the rotation of the electric motor 15 is stopped, and the vehicle 1 is brought into a stopped state (parking lock state). At this time, even if the accelerator pedal 21 is depressed, the energization stop unit 16 continues the energization stop process, and thus the power supply to the electric motor 15 is kept stopped, and the stopped state of the vehicle 1 is maintained.

On the other hand, when the driver requests the release of the parking lock by operating the shift lever 5 to a position other than the parking position P or by operating the parking switch, the VCU 2 outputs a parking lock release instruction signal to the ECU 3.

In step S17, when the parking lock release instruction signal is not detected by the parking lock signal detection unit 14 of the inverter circuit 10, the inverter circuit 10 continues to stop the supply of power to the electric motor 15.

On the other hand, when the parking lock release instruction signal is detected by the parking lock signal detection unit 14 in step S17, the inverter circuit 10 of the MCU 9 stops the operation of the energization stop unit 16 and starts supplying power to the electric motor 15 in step S19.

When the parking lock release command is detected and the electric motor 15 starts to be energized in this way, the inverter circuit 10 controls the motor rotation angle so that the electric motor 15 does not rotate by a predetermined angle or more due to an external force in step S21.

Specifically, the inverter circuit 10 obtains a rotation angle (rotation angle position) of the electric motor 15 based on a signal from a position detector 17, which is a rotation angle sensor (MR sensor) disposed near the electric motor 15, and controls the electric power supplied to the electric motor 15 so that the rotation angle is within a fixed range. As a result, the rotation of the electric motor 15 due to the external force can be suppressed, and the vehicle 1 can be prevented from moving after the parking lock is released.

In addition, when a resolver is used as the position detector 17, for example, the detection accuracy of the rotational position and the durability at high temperature can be improved as compared with a hall element or the like. On the other hand, when the hall element is used, it can be configured at a lower cost than a resolver, an encoder, or the like.

In this way, when the parking lock is released from the stopped state by the parking lock, the inverter circuit 10 controls the electric motor 15 by Hill Hold Control (Hill Hold Control) so as to apply a Hill Hold braking force according to a vehicle environment (for example, a Hill or the like) to the vehicle 1. Thus, even when the locked state by the parking lock is released, the stopped state of the vehicle 1 can be maintained on a slope or the like.

When the release operation of the hill hold function, for example, the accelerator pedal 21 is operated, is detected in step S23, the inverter circuit 10 outputs an instruction signal for releasing the locked state to the parking lock mechanism 12 (step S25). Thereafter, in step S27, the inverter circuit 10 performs normal motor drive control for supplying power to the electric motor 15 in accordance with a command signal from the ECU 3.

In addition, the following structure may be adopted: the inverter circuit 10 further includes an output unit that outputs an operation instruction to the parking lock mechanism 12 that mechanically locks the drive wheels of the vehicle 1. In this way, the drive wheels of the vehicle 1 can be mechanically locked from rotation in response to the operation instruction of the parking lock from the inverter circuit 10, and therefore the control load of the higher-level electronic control unit (e.g., the ECU 3) can be reduced.

In addition, when the parking lock instruction is detected in step S11, the inverter circuit 10 may be configured to notify a host controller such as the VCU 2 of the detection. In step S15, the upper controller may be notified of the stop of the drive current to the electric motor 15 in response to the parking lock instruction. In this way, the control state of the inverter circuit 10 can be confirmed by the higher-level controller.

On the other hand, by mounting the inverter circuit 10 in an inverter control device for driving an electric motor of a vehicle and controlling the electric motor, it is possible to suppress heat generation of the inverter control device and the electric motor during parking lock of the vehicle and to suppress power consumption of a battery.

As described above, the inverter circuit according to the present embodiment is configured to stop the drive current to the electric motor by the energization stop unit when the lock instruction detection unit detects a parking lock instruction for suppressing rotation of the drive wheels of the vehicle when the electric motor as the drive source of the vehicle is driven.

In this way, by configuring such that the parking lock state is recognized by the inverter circuit and the electric motor is not energized even if the accelerator pedal is operated, it is possible to suppress heat generation (temperature rise) of the inverter circuit and the electric motor during parking lock of an electric vehicle or the like to avoid a failure and to suppress power consumption of the battery.

Further, since the parking lock state of the vehicle is established by stopping the motor control for supplying power from the inverter circuit to the electric motor, the parking lock can be performed without using the mechanical parking lock mechanism, and the higher-level Electronic Control Unit (ECU) does not perform the accompanying energization control to the electric motor, recognition of the parking lock state, and the like, and thus the control load can be reduced.

< second embodiment >

As shown in fig. 2, the inverter circuit 10 includes a parking lock signal detection unit 14, a parking state detection unit 24, a parking lock release unit 26, and the like, which will be described later, in addition to the motor drive unit 18.

Therefore, when the parking lock signal detection unit 14 provided in the inverter circuit 10 in the MCU 9 detects the parking lock instruction signal transmitted from the VCU 2 via the ECU 3 in step S111 in fig. 5, it determines whether or not a predetermined hill hold condition is satisfied in step S113.

As the hill hold condition, for example, it is determined whether or not the operation amount (accelerator opening degree) of the accelerator pedal 21 is 0 and the brake pedal 23 is depressed, and the vehicle speed based on the detection signal from the vehicle speed sensor 31 is equal to or less than a predetermined value. The vehicle speed may be obtained by providing an output shaft rotation sensor in the electric motor 15 and based on a signal detected by the output shaft rotation sensor. In addition, the information may be acquired from another controller of the vehicle through communication based on an in-vehicle network such as CAN communication.

When the hill hold condition is satisfied, whether the electric motor 15 is stopped or not is checked in step S115. When the electric motor 15 is not stopped, the inverter circuit 10 of the MCU 9 controls the motor rotation angle so that the rotor rotation angle of the electric motor 15 becomes equal to or smaller than a predetermined angle in step S117.

Here, the rotation angle (rotation angle position) of the electric motor 15 is obtained based on a signal from a position detector 17, which is a rotation angle sensor (MR sensor) disposed in the vicinity of the electric motor 15, and the supply of electric power to the electric motor 15 is controlled so that the rotation angle becomes equal to or smaller than a certain value.

In the next step S119, the inverter circuit 10 detects, by the parking state detector 24, whether or not the parking lock mechanism 12 is activated to disable the mechanical rotation (locked state) of the drive wheels (

wheels

13a and 13b) of the vehicle 1.

During the period from the detection of the parking lock instruction in step S111 to the detection of the locked state of the drive wheels in step S119, the inverter circuit 10 controls the electric motor 15 so that the rotor rotation angle is equal to or less than a certain value in step S117. Thereby, the stopped state of the vehicle 1 is maintained even if the accelerator pedal 21 is depressed.

That is, during a period from the time when the parking lock instruction is issued to the time when the mechanical lock is fully activated (until the parking gear 32 is fitted to the parking column 34 in fig. 3), the parking lock function is operated by the motor control by the inverter circuit 10, and thus the vehicle 1 can be kept stationary during this period. In addition, the time from the issuance of the parking lock instruction until the vehicle 1 can maintain the stopped state can be shortened.

Further, even when the mechanical parking lock function is not operated due to a failure or the like and the parking state detection unit 24 does not detect the locked state, the vehicle 1 can be kept stopped by the parking lock function based on the motor control of the inverter circuit 10.

When it is detected in step S119 that the drive wheels are in the locked state, the inverter circuit 10 detects whether or not a parking lock release instruction signal is input from the VCU 2 via the ECU 3 by the parking lock signal detection unit 14 in step S121. The parking lock release instruction signal is output in response to a request for releasing the parking lock, such as a driver operating the shift lever 5 to a position other than the parking position P or operating a parking switch.

When the parking lock release instruction signal is detected in step S121, the inverter circuit 10 stops the control of the rotor rotation angle in the next step S123.

In step S125, the inverter circuit 10 determines whether or not an instruction signal instructing the parking lock mechanism 12 to release the locked state is detected, for example, a signal corresponding to an operation of the brake pedal 23 or an operation of the accelerator pedal 21 of the vehicle 1.

When the instruction signal is detected, the inverter circuit 10 outputs an instruction signal for releasing the locked state to the parking lock mechanism 12 via the parking lock release unit 26 in step S27.

For example, the parking lock release unit 26 releases the parking lock function based on a predetermined signal corresponding to an operation of depressing the accelerator pedal 21 immediately after depressing the brake pedal 23 or an operation of depressing the accelerator pedal 21 a predetermined number of times within a predetermined time period.

Since the parking lock function can be actively released by the inverter circuit 10, the electric motor 15 can be rotated from the parking lock state to move the vehicle 1. This makes it possible to smooth and simplify the transition from the parking lock state to the start of the normal running. In addition, by preparing a plurality of methods for releasing the parking lock function in addition to the operation of the normal lock release button, the convenience of the vehicle operation is improved.

In the next step S129, the inverter circuit 10 performs normal motor drive control for supplying power to the electric motor 15 in accordance with a command signal from the ECU 3.

Further, the inverter circuit 10 may further include a signal output unit configured to output a signal indicating that the parking lock mechanism 12 is not locked when the parking state detection unit 24 serving as the locked state detection unit does not detect the locked state.

In this way, the absence of the mechanical lock function in the parking lock mechanism 12 can be transmitted to a higher-level Electronic Control Unit (ECU). As a result, the higher-level unit can warn (warn) the driver that the mechanical lock function is not operating, provide information about the dealer, the maintenance plant, and the like, and prompt handling for the non-operation.

Further, the inverter circuit 10 may be provided with a signal generating portion that generates a signal requesting the parking lock function of the parking lock mechanism 12 or a signal executing the parking lock function of the parking lock mechanism 12 when a stop time of the vehicle 1 by the hill hold braking force reaches a certain time or more (for example, 30 seconds or more or 1 minute or more) when the hill hold braking force by the hill hold control is applied to the vehicle 1.

When the vehicle 1 is stopped for a certain time or more in the hill hold state, the driving wheels (

wheels

13a, 13b) of the vehicle 1 are mechanically locked by the parking lock mechanism 12, whereby convenience can be improved and power consumption of the battery BT can be suppressed.

Further, the inverter circuit 10 may generate a signal for releasing the parking lock state when starting the vehicle 1 from the hill hold state.

In this case, for example, by controlling so that the parking lock can be automatically released from the hill hold state only by the accelerator operation, it is not known that the driver in the parking lock can start the vehicle 1 by the same instruction (operation) as in the case of the normal shift from the hill hold state to the travel state. Further, since the parking lock state can be promptly released, the power consumption can be suppressed.

As described above, the inverter circuit according to the second embodiment is configured to control the electric motor such that the rotor rotation angle of the electric motor becomes equal to or less than a certain value, based on the detection result from the position detector that detects the rotor rotation angle of the electric motor, when the parking lock signal detection unit detects a parking lock instruction for suppressing the rotation of the drive wheels of the vehicle when the electric motor that is the drive source of the vehicle is driven. The parking lock function can be realized by the motor control based on the inverter circuit having such a configuration.

In addition, when the vehicle has a parking lock mechanism for mechanically locking the drive wheels, the vehicle can be configured as a redundant structure that combines the mechanical parking lock function and the parking lock function by the motor control using the inverter circuit. As a result, even when the parking lock mechanism is not operated due to a failure or the like, the stable stopped state of the vehicle can be maintained by the parking lock function based on the motor control.

Thus, the parking lock function controlled by the motor of the inverter circuit can be used as a backup or a substitute for the mechanical parking lock mechanism, and the redundancy of the parking lock function can be improved, thereby reducing the burden on the driver.

Claims

1. An inverter circuit for driving an electric motor as a drive source of a vehicle,

the inverter circuit includes:

a parking lock instruction detection unit that detects a parking lock instruction that suppresses rotation of a drive wheel of the vehicle; and

and an energization stop unit that stops a drive current to the electric motor when the parking lock instruction is detected.

2. The inverter circuit according to claim 1,

the inverter circuit further has a unit that outputs a signal notifying that the parking lock instruction is detected.

3. The inverter circuit according to claim 1,

the inverter circuit further includes a unit that outputs a signal notifying that the driving current to the electric motor is stopped in accordance with the parking lock instruction.

4. The inverter circuit according to claim 1,

the inverter circuit further includes a means for outputting an operation instruction to a parking lock mechanism for mechanically locking a drive wheel of the vehicle.

5. The inverter circuit according to any one of claims 1 to 4,

the inverter circuit further includes:

a lock release detection unit that detects a release instruction of the parking lock; and

and a control unit that, when the release command is detected, controls the electric motor so as not to rotate by a predetermined angle or more due to an external force.

6. The inverter circuit according to claim 5,

the control unit controls the electric motor so that a hill hold braking force based on hill hold control is applied to the vehicle.

7. An inverter control device for driving an electric motor, wherein,

the inverter control device performs drive control of the electric motor by the inverter circuit according to any one of claims 1 to 6.

8. A vehicle drive device having the inverter control device according to claim 7.

9. An inverter circuit for driving an electric motor as a drive source of a vehicle,

the inverter circuit includes:

a parking lock instruction detection unit that detects a parking lock instruction that suppresses rotation of a drive wheel of the vehicle;

a rotation angle detection unit that detects a rotation angle of a rotor of the electric motor; and

and a control unit that controls the electric motor so that the rotor rotation angle is equal to or less than a predetermined value when the parking lock instruction is detected.

10. The inverter circuit according to claim 9,

the inverter circuit further has a parking lock state detection section that detects a lock state of a parking lock mechanism that mechanically locks drive wheels of the vehicle,

the control unit controls the electric motor such that the rotor rotation angle is equal to or less than a predetermined value during a period from when the parking lock instruction is detected by the parking lock instruction detection unit to when the locked state is detected by the parking lock state detection unit.

11. The inverter circuit according to claim 10,

the inverter circuit further includes a signal output unit that outputs a signal indicating that the parking lock state detection unit has not detected the locked state.

12. The inverter circuit according to any one of claims 9 to 11,

the inverter circuit further includes a parking lock release unit that releases the parking lock function in accordance with a predetermined signal.

13. The inverter circuit according to claim 12,

the predetermined signal is a signal output in accordance with a brake pedal operation and an accelerator pedal operation of the vehicle.

14. The inverter circuit according to claim 9,

the inverter circuit further includes:

a hill hold control unit that applies a hill hold braking force based on hill hold control to the vehicle; and

and a signal generating unit that generates a signal requesting a parking lock function of the parking lock mechanism or a signal executing the parking lock function of the parking lock mechanism when a stop time of the vehicle based on the hill hold braking force is equal to or longer than a predetermined time.

15. The inverter circuit of claim 14,

the hill hold control unit generates a signal to release the parking lock when the vehicle is to be started from the hill hold state.

16. An inverter control device for driving an electric motor, wherein,

the inverter control device performs drive control of the electric motor by the inverter circuit according to any one of claims 9 to 15.

17. A vehicle drive device having the inverter control device according to claim 16.