Electric vehicle

• US 9,428,079 B2
• Filed: 10/15/2014
• Issued: 08/30/2016
• Est. Priority Date: 10/17/2013
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ota, Takashi
• Primary Examiner(s): HOLLOWAY, JASON R
• Application Number:
  US14/514,914
• Publication Number:
  US 20150112535A1
• Time in Patent Office: 685 Days
• US Class Current: 1/1
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/36 with automatic control superimposed, e.g. to prevent excessive motor current
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/42 with use of more than one motor
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/425 Temperature
• CPC Class Codes: B60L 2240/429 Current
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 2260/28 Four wheel or all wheel drive
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

An electric vehicle includes: a synchronous motor; an induction motor; and a control unit configured to adjust a torque from the synchronous motor and a torque from the induction motor, wherein the control unit includes a torque varying device configured to reduce an output torque from the synchronous motor while maintaining a total drive force of the electric vehicle, and increasing an output torque from the induction motor in the case where the electric vehicle is stopped in a state in which a torque is output from the synchronous motor. Accordingly, there is provided an electric vehicle capable of restraining deterioration of drivability and performing thermal protection of a motor and a control unit.

Claims

1. An electric vehicle comprising:

a synchronous motor for driving the electric vehicle;

an induction motor for driving the electric vehicle; and

a control unit configured to adjust a torque from the synchronous motor and a torque from the induction motor, wherein

the control unit includes a torque conversion program configured to maintain or reduce an output torque from the synchronous motor and increase an output torque from the induction motor while maintaining a total drive force of the electric vehicle when the electric vehicle is stopped in a state in which a torque command of the synchronous motor is greater than zero.

2. The electric vehicle according to claim 1, wherein

the torque conversion program of the control unit

stops an output of the torque from the synchronous motor, and changes the output torque from the induction motor into a torque corresponding to the total drive force of the electric vehicle.

5. The electric vehicle of claim 1, wherein the control unit is further configured to:

determine whether an electric frequency of the synchronous motor falls between −

A and A;

determine whether a phase current of the synchronous motor is greater than or equal to C₂; and

maintain the torque command of the synchronous motor and increase a torque command of the induction motor when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.

6. The electric vehicle of claim 1, wherein the control unit is further configured to:

determine whether an electric frequency of the synchronous motor falls between −

A and A;

determine whether a phase current of the synchronous motor is greater than or equal to C₂; and

reduce the torque command of the synchronous motor and increase a torque command of the induction motor when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.

7. The electric vehicle of claim 1, wherein the control unit is further configured to:

determine whether an electric frequency of the synchronous motor falls between −

A and A;

determine whether a phase current of the synchronous motor is greater than or equal to C₂; and

reduce the torque command of the synchronous motor to zero and increase a torque command of the induction motor such that the output torque of the induction motor corresponds to the total drive force of the electric vehicle when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.

3. An electric vehicle comprising:

a synchronous motor for driving the electric vehicle;

an induction motor for driving the electric vehicle; and

a control unit including a CPU, and configured to adjust a torque from the synchronous motor and a torque from the induction motor, wherein

the control unit executes a torque conversion program that, when executed by the CPU, reduces or maintains an output torque from the synchronous motor and increases an output torque from the induction motor while maintaining a total drive force of the electric vehicle when the electric vehicle is stopped in a state in which a torque command of the synchronous motor is greater than zero.

8. The electric vehicle of claim 3, wherein the control unit is further configured to:

determine whether an electric frequency of the synchronous motor falls between −

A and A;

determine whether a phase current of the synchronous motor is greater than or equal to C₂; and

maintain the torque command of the synchronous motor and increase a torque command of the induction motor when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.

9. The electric vehicle of claim 3, wherein the control unit is further configured to:

determine whether an electric frequency of the synchronous motor falls between −

A and A;

determine whether a phase current of the synchronous motor is greater than or equal to C₂; and

reduce the torque command of the synchronous motor and increase a torque command of the induction motor when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.

10. The electric vehicle of claim 3, wherein the control unit is further configured to:

determine whether an electric frequency of the synchronous motor falls between −

A and A;

determine whether a phase current of the synchronous motor is greater than or equal to C₂; and

reduce the torque command of the synchronous motor to zero and increase a torque command of the induction motor such that the output torque of the induction motor corresponds to the total drive force of the electric vehicle when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.

4. A method of controlling an electric vehicle including:

a synchronous motor for driving the electric vehicle;

an induction motor for driving the electric vehicle; and

a control unit configured to adjust a torque from the synchronous motor and a torque from the induction motor, comprising;

reducing or maintaining an output torque from the synchronous motor and increasing an output torque from the induction motor while maintaining a total drive force of the electric vehicle when the electric vehicle is stopped in a state in which a torque command of the synchronous motor is greater than zero.

11. The method of claim 4, further comprising:

determining whether an electric frequency of the synchronous motor falls between −

A and A;

determining whether a phase current of the synchronous motor is greater than or equal to C₂; and

maintaining the torque command of the synchronous motor and increasing a torque command of the induction motor when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.

12. The method of claim 4, further comprising:

determining whether an electric frequency of the synchronous motor falls between −

A and A;

determining whether a phase current of the synchronous motor is greater than or equal to C₂; and

reducing the torque command of the synchronous motor and increasing a torque command of the induction motor when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.

13. The method of claim 4, further comprising:

determining whether an electric frequency of the synchronous motor falls between −

A and A;

determining whether a phase current of the synchronous motor is greater than or equal to C₂; and

reducing the torque command of the synchronous motor to zero and increasing a torque command of the induction motor such that the output torque of the induction motor corresponds to the total drive force of the electric vehicle when the electric frequency of the synchronous motor falls between −

A and A and the phase current of the synchronous motor is greater than or equal to C₂.