Motor Control Device, Motored Vehicle Equipped Therewith, and Method of Controlling a Motor

• US 20080315814A1
• Filed: 04/03/2007
• Published: 12/25/2008
• Est. Priority Date: 04/24/2006
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Takizawa, Keiji, Aihara, Hiroshi
• Granted Patent: US 8,089,234 B2
• Time in Patent Office: Days
• US Class Current: 318/434
• CPC Class Codes: B60L 15/00 Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

When a motor temperature exceeds a threshold value, a torque control unit reduces a torque control value for a motor generator. A torque limitation control unit determines from torque control value and vehicular speed whether limiting a torque by the torque control unit should be alleviated, and if so the torque limitation control unit activates a signal for a predetermined period of time. When the signal is activated, the torque control unit stops reducing the torque control value and fixes the torque control value to be constant.

Claims

1. An electric motor control device apparatus controlling an electric motor generating a force driving a vehicle, comprising:

a torque limitation device to limit a torque of said electric motor; and

a torque limitation alleviation device to output an instruction to said torque limitation means device for a predetermined period of time to alleviate said limiting of said torque in accordance with a state of said vehicle after said torque limitation device starts said limiting of said torque of said electric motor, wherein

said predetermined period of time is a period of time preset as a time allowing a driver of said vehicle to handle a state of said vehicle caused by said limiting of said torque

3. The electric motor control apparatus according to claim 1, wherein said torque limitation alleviation device outputs said instruction to said torque limitation device when said electric motor provides a torque exceeding a first threshold value and said vehicle has a speed smaller than a second threshold value.

4. The electric motor control apparatus according to claim 1, wherein said torque limitation device controls said torque of said electric motor to have a constant value when said torque limitation device receives said instruction from said torque limitation alleviation device.

5. The electric motor control apparatus according to claim 1, wherein after said predetermined period of time has elapsed, said torque limitation alleviation means device outputs an instruction to said torque limitation means device to remove alleviating the limiting of said torque.

6. The electric motor control apparatus according to claim 5, further comprising a notification device to output an alarm to a driver of said vehicle when alleviating said limiting of said torque is removed.

7. A motored vehicle comprising:

an electric motor generating a force driving the vehicle;

a wheel mechanically coupled with an output shaft of said electric motor; and

the electric motor control apparatus of claim 1.

2. (canceled)

8. A method of controlling an electric motor generating a force driving a vehicle, comprising the steps of:

limiting a torque of said electric motor; and

after the step of limiting is started, alleviating said limiting of said torque for a predetermined period of time in accordance with a state of said vehicle, wherein

said predetermined period of time is a period of time preset as a time allowing a driver of said vehicle to handle a state of said vehicle caused by said limiting of said torque.

10. The method according to claim 8, wherein the step of alleviating includes the sub-steps of:

determining whether said electric motor provides a torque exceeding a first threshold value;

determining whether said vehicle has a speed smaller than a second threshold value; and

alleviating said limiting of said torque for said predetermined period of time when said electric motor provides said torque exceeding said first threshold value and said vehicle has said speed smaller than said second threshold value.

11. The method according to claim 8, wherein the step of alleviating includes controlling said torque of said electric motor to be constant only for said predetermined period of time.

12. The method according to claim 8, further comprising the step of removing alleviating the limiting of said torque after said predetermined period of time has elapsed.

13. The method according to claim 12, further comprising the step of outputting an alarm to a driver of said vehicle when alleviating the limiting of said torque is removed.

9. (canceled)