Control device for electric motor vehicle and control method for electric motor vehicle

Patent metadata

Field	Value
Publication number	US-9902272-B2
Application number	US-201315100886-A
Country	US
Kind code	B2
Filing date	Dec 2, 2013
Priority date	Dec 2, 2013
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A control device for electric motor vehicle is configured to decelerate by a regenerative braking force of the motor when an accelerator operation amount decreases or becomes zero. The control device detects the accelerator operation amount, calculates a motor torque command value, and controls the motor on the basis of the motor torque command value calculated. The control device detects a speed parameter proportional to a traveling speed and calculates a feedback torque for stopping the vehicle on the basis of the speed parameter detected. The control device also estimates a disturbance torque acting on the motor and converges, as the speed parameter is reduced, the motor torque command value to the disturbance torque on the basis of the feedback torque when the accelerator operation amount decreases or becomes zero and the electric motor vehicle stops shortly. The control device adjusts the feedback torque according to the disturbance torque.

First claim

The invention claimed is:

1. A control device for an electric motor vehicle using an electric motor as a traveling drive source, the control device comprising:
an accelerator pedal for instructing the acceleration/deceleration and stopping of the vehicle;
a motor controller configured to:
detect an accelerator operation amount indicating an operating state of the accelerator pedal;
estimate a disturbance torque acting on the electric motor;
detect a speed parameter proportional to a traveling speed of the electric motor vehicle;
calculate a feedback torque for stopping the electric motor vehicle on a basis of the detected speed parameter;
calculate a motor torque command value; and
control the electric motor on a basis of the motor torque command value,

wherein the electric motor is configured to decelerate, by a regenerative braking force of the electric motor, when the accelerator operation amount decreases or becomes zero;
wherein the motor controller converges, as the speed parameter is reduced, the motor torque command value to the disturbance torque on a basis of the feedback torque when the accelerator operation amount decreases or becomes zero and the electric motor vehicle stops just before a stop of the vehicle; and
wherein the motor controller adjusts the feedback torque according to the disturbance torque when the electric motor vehicle is decelerated and stops just before the stop of the vehicle by the operation of the accelerator pedal.

2. The control device for the electric motor vehicle according to claim 1 , wherein:
The motor controller calculates the feedback torque by multiplying the speed parameter by a predetermined gain for generating the regenerative braking force of the electric motor; and
the predetermined gain is changed on a basis of the disturbance torque.

3. The control device for the electric motor vehicle according to claim 2 , wherein the motor controller is configured to set the predetermined gain to make the regenerative braking force of the electric motor smaller than on a flat road when a road surface is judged to be uphill on the basis of the disturbance torque.

4. The control device for the electric motor vehicle according to claim 2 , wherein the motor controller is configured to:
calculate a first torque target value on a basis of vehicle information including an accelerator pedal opening and a motor rotation speed;
calculate a second torque target value, the second torque target value converging to the disturbance torque on a basis of the feedback torque as the detected speed parameter is reduced;
calculate a just-before-stop judgment torque by multiplying the detected speed parameter by the predetermined gain; and
compare magnitudes of the first torque target value and the just-before-stop judgment torque,
wherein the motor controller judges that the vehicle stop just before the stop of the vehicle, switches the motor torque command value from the first torque target value to the second torque target value, sets a gain of the feedback torque on the basis of the disturbance torque and maintains the gain until the vehicle stops when the just-before-stop judgment torque is judged to be larger than the first torque target value.

5. The control device for the electric motor vehicle according to claim 1 , wherein the motor controller is configured to:
estimate the speed parameter; and
calculate a feedforward torque for compensating for the feedback torque on a basis of the estimated speed parameter,
wherein the motor controller converges, as the speed parameter is reduced, the motor torque command value to the disturbance torque on a basis of the feedback torque and the feedforward torque when the accelerator operation amount decreases or becomes zero and the electric motor vehicle stops just before the stop of the vehicle.

6. The control device for the electric motor vehicle according to claim 5 , wherein:
the motor controller calculates the feedback torque by multiplying the detected speed parameter by a predetermined gain K 1 for distributing the regenerative braking force of the electric motor;
the motor controller calculates the feedforward torque by multiplying the estimated speed parameter by a predetermined gain K 2 , the gain K 2 being set at a smaller value as the predetermined gain K 1 increases; and
the motor controller sets a speed feedback torque obtained by adding the feedforward torque to the feedback torque as the motor torque command value when the accelerator operation amount decreases or becomes zero and the electric motor vehicle stops just before the stop of the vehicle.

7. The control device for the electric motor vehicle according to claim 6 , wherein the predetermined gain K 2 is set at a value obtained by subtracting the predetermined gain K 1 from a total gain Kvref determined to converge the speed feedback torque to zero.

8. The control device for the electric motor vehicle according to claim 6 , wherein the motor controller is configured to change the predetermined gain K 2 on a basis of the disturbance torque when the accelerator operation amount decreases or becomes zero and the electric motor vehicle stops just before the stop of the vehicle.

9. The control device for the electric motor vehicle according to claim 8 , wherein the motor controller sets the predetermined gain K 2 such that the regenerative braking force of the electric motor is smaller than on a flat road when a road surface is judged to be uphill on the basis of the disturbance torque.

10. A control method for an electric motor vehicle using an electric motor as a traveling drive source, the control method comprising:
detecting, by a motor controller, an accelerator operation amount indicating an operating state of an accelerator pedal for instructing acceleration/deceleration and stopping of the vehicle;
estimating, by the motor controller, a disturbance torque acting on the electric motor;
detecting, by the motor controller, a speed parameter proportional to a traveling speed of the electric motor vehicle;
calculating, by the motor controller, a feedback torque for stopping the electric motor vehicle on a basis of a detected speed parameter;
calculating, by the motor controller, a motor torque command value; and
controlling, by the motor controller, the electric motor on a basis of the motor torque command value;
wherein the electric motor is configured to decelerate by a regenerative braking force of the electric motor when the accelerator operation amount decreases or becomes zero;
wherein the calculating the motor torque command value includes converging, as the speed parameter is reduced, the motor torque command value to the disturbance torque on a basis of the feedback torque when the accelerator operation amount decreases or becomes zero and the electric motor vehicle stops just before the stop of a vehicle; and
wherein the calculating the feedback torque includes adjusting the feedback torque according to the disturbance torque when the electric motor vehicle is decelerated and stops just before the stop of the vehicle by the operation of the accelerator pedal.

Assignees

• Nissan Motor

Inventors

• Sawada Akira
• Ito Ken
• Nakajima Takashi
• Katsumata Yuji
• Komatsu Hiroyuki

Classifications

• B60L7/18 Primary

  Controlling the braking effect (B60L7/12, B60L7/14, B60L7/16 take precedence) · CPC title

• B60L2240/423

  Torque · CPC title

• B60L15/20

  for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed · CPC title

• Y02T90/16

  Information or communication technologies improving the operation of electric vehicles · CPC title

• B60L15/2018

  for braking on a slope · CPC title