Vehicle and electric motor control method for vehicle

Patent metadata

Field	Value
Publication number	US-9887663-B2
Application number	US-201715447129-A
Country	US
Kind code	B2
Filing date	Mar 2, 2017
Priority date	Mar 4, 2016
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

A vehicle includes an electric motor to move the vehicle. A motor driver is configured to convert direct-current power supplied from a voltage converter to an alternating-current power and to convert the alternating-current power supplied from the electric motor to direct-current power. Circuitry is configured to drive the electric motor with a first current value to generate a drive force to consume excess electric power. The first current value is different from a minimum current value to generate the same drive force. The circuitry is configured to drive the electric motor with a second current value smaller than the first current value to decrease the electric power consumption of the electric motor when a temperature of the electric motor exceeds a first threshold temperature or a temperature of the motor driver exceeds a second threshold temperature.

First claim

What is claimed is:

1. A vehicle comprising:
an energy storage device;
a drive device capable of two-way conversion between direct current and alternating current;
a rotating electric motor connected to an alternating current side of the drive device, and having an output shaft connected to a load;
a voltage transformer having a low voltage side connected to the energy storage device and a high voltage side connected to a direct current side of the drive device, the voltage transformer stepping up the voltage of the energy storage device, and applying the stepped-up voltage to the rotating electric motor through the drive device; and
a controller that controls the drive device, the rotating electric motor, and the voltage transformer;
the controller driving the rotating electric motor with a first current value, different from a minimum current value for the rotating electric motor to generate a specific drive force, so as to cause excess electric power to be consumed by the rotating electric motor, while also, when a temperature of the rotating electric motor or a temperature of the drive device exceeds a threshold temperature value, driving the rotating electric motor with a second current value smaller than the first current value and decreasing the electric power consumption of the rotating electric motor.

2. The vehicle according to claim 1 , wherein, when changing a phase current supplied to the rotating electric motor from the first current value to the second current value, the controller decreases the phase current along an equivalent torque line.

3. The vehicle according to claim 1 ,
wherein the controller expands a running range of the rotating electric motor by stepping up the voltage of the energy storage device using the voltage transformer, and drives the rotating electric motor in the expanded running range such that current supplied to the rotating electric motor is the first current value, and
wherein when the temperature of the rotating electric motor or the temperature of the drive device exceeds the threshold temperature value, the controller lowers the stepped-up voltage and contracts the running range, and drives the rotating electric motor in the contracted running range such that the current supplied to the rotating electric motor is the second current value.

4. The vehicle according to claim 1 , wherein, when excess electric power generated by the vehicle is regeneration power arising from braking use, and the regeneration power is not all consumable in the rotating electric motor, the controller sets braking force for the non-consumable portion of regeneration power to be provided by mechanical braking.

5. The vehicle according to claim 1 , wherein the temperature of the rotating electric motor is a temperature of a field coil configuring the rotating electric motor or a temperature of a cooling medium for cooling the rotating electric motor, and the temperature of the drive device is a temperature of a semiconductor switching element configuring the drive device.

6. The vehicle according to claim 1 , wherein the rotating electric motor is operated under strong field control to expand a running range of the rotating electric motor.

7. The vehicle according to claim 1 ,
wherein the drive device is a first drive device,
wherein the load is an internal combustion engine,
wherein the rotating electric motor is a first rotating electric motor, and
wherein the vehicle further comprises
a second rotating electric motor having a wheel as a load, and
a second drive device having an alternating current side connected to the second rotating electric motor and a direct current side connected to the high voltage side of the voltage transformer, and

wherein excess electric power generated by the vehicle is part or all of regeneration power generated by the second rotating electric motor.

8. A vehicle comprising:
an energy storage to supply a first voltage;
an electric motor to move the vehicle;
a voltage converter connected to the energy storage to convert the first voltage to a second voltage higher than the first voltage;
a motor driver via which the voltage converter is connected to the electric motor and which is configured to convert direct-current power supplied from the voltage converter to an alternating-current power and to convert the alternating-current power supplied from the electric motor to direct-current power; and
circuitry configured to
drive the electric motor with a first current value to generate a drive force to consume excess electric power, the first current value being different from a minimum current value to generate the same drive force, and
drive the electric motor with a second current value smaller than the first current value to decrease the electric power consumption of the electric motor when a temperature of the electric motor exceeds a first threshold temperature or a temperature of the motor driver exceeds a second threshold temperature.

9. The vehicle according to claim 8 , wherein when changing a phase current supplied to the electric motor from the first current value to the second current value, the circuitry decreases the phase current along an equivalent torque line.

10. The vehicle according to claim 8 ,
wherein the circuitry is configured to control the voltage converter to increase the second voltage to a third voltage to expand a running range of the electric motor to a first running range, and to drive the electric motor in the first running range such that a value of current supplied to the electric motor is the first current value, and
wherein the circuitry is configured to decrease the second voltage to a fourth voltage lower than the third voltage to shrink the running range to a second running range smaller than the first running range to drive the electric motor in the second running range such that the current supplied to the electric motor is the second current value when the temperature of the electric motor exceeds the first threshold temperature or the temperature of the motor driver exceeds the second threshold temperature.

11. The vehicle according to claim 8 , wherein, when excess electric power generated by the vehicle is regeneration power arising from braking force, and the regeneration power is not all consumable in the electric motor, the circuitry is configured to control the mechanical brake to generate the braking force to consume a non-consumable portion of the regeneration power.

12. The vehicle according to claim 8 , wherein the temperature of the electric motor is a temperature of a field coil configuring the electric motor or a temperature of a cooling medium for cooling the electric motor, and the temperature of the motor driver is a temperature of a semiconductor switching element configuring the motor driver.

13. The vehicle according to claim 8 , wherein the electric motor is operated under strong field control to expand a running range of the electric motor.

14. The vehicle according to claim 8 ,
wherein the load is an internal combustion engine,
wherein the vehicle further comprises
an additional electric motor connected to a wheel as a load of the additional electric motor, and
an additional motor driver to convert the direct-current power to another alternating-current power to supply the another alternating-current power to the another electric motor, and

wherein excess electric power generated by the vehicle is part or all of regeneration power generated by the another electric motor.

15. An electric motor control method for a vehicle, comprising:
driving an electric motor with a first

Assignees

• Honda Motor Co Ltd

Inventors

• Kitaori Ken
• Fukuchi Masanari
• Ito Yoshihiro
• Matsui Satoshi

Classifications

• B60W2510/087

  Temperature · CPC title

• B60K6/46

  Series type · CPC title

• B60W2510/246

  Temperature · CPC title

• B60K6/442

  Series-parallel switching type · CPC title

• B60W20/15

  Control strategies specially adapted for achieving a particular effect · CPC title