Control device for electric vehicle and control method for electric vehicle
The control device for the electric vehicle determines whether or not the starting operation of the vehicle has been performed by the driver, calculates the disturbance torque estimated value Td necessary for maintaining the vehicle stop state corresponding to the disturbance acting on the vehicle, and performs a control such that the driving torque of the motor converges to the disturbance torque estimated value Td when the vehicle is determined to be just before stop of the vehicle during running or determined to have undergone the starting operation. Then, the control device for the electric vehicle controls the responsiveness of the driving torque to the disturbance acting on the vehicle, and increases the responsiveness of the driving torque of the motor compared with the responsiveness of the driving torque just before stop of the vehicle when the starting operation is determined to have been performed.
1. A control device for an electric vehicle, the electric vehicle including a motor that generates a driving torque and a controller that controls the motor, the controller configured to:
determine whether an initial start operation of a vehicle has been performed by a driver, the initial start operation being not performed with an accelerator operation;
calculate a disturbance torque estimated value necessary for maintaining a vehicle stop state corresponding to a disturbance acting on the vehicle;
perform a control such that the driving torque of the motor converges to the disturbance torque estimated value when the vehicle is determined to be just before stop of the vehicle during running or determined to have undergone the initial start operation; and
increase, when the initial start operation is determined to have been performed, the responsiveness of the driving torque of the motor compared with a responsiveness of the driving torque just before the stop of the vehicle.
2. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
determines that determine the initial start operation has been performed when the controller detects a transition of an ignition switch signal of the vehicle from an OFF state to an ON state.
3. The control device for the electric vehicle according to claim 2 , wherein the controller is configured to:
obtain an accelerator position by the driver,
obtain a motor rotation speed or a speed parameter proportional to the motor rotation speed, and
determine that the initial start operation has been performed when the controller detects a transition of the ignition switch signal of the vehicle from the OFF state to the ON state, the amount of the accelerator operation is zero, and the absolute value of the motor rotation speed or an absolute value of the speed parameter is equal to or more than a predetermined value.
4. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
obtain a motor rotation speed or a speed parameter proportional to the motor rotation speed,
use a speed feedback control system that performs a feedback of the obtained motor rotation speed or the speed parameter, so as to calculate the disturbance torque estimated value, and
increase a feedback gain of the speed feedback control system when the initial start operation is determined to have been performed, so as to increase the responsiveness of the driving torque.
5. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
include a filter having a predetermined damping coefficient constituted of a quadratic expression as a numerator and a quadratic expression as a denominator, and calculates the disturbance torque estimated value damped on the basis of the damping coefficient of the filter, and
decrease a damping coefficient of the denominator of the filter when the initial start operation is determined to have been performed, so as to increase the responsiveness of the driving torque.
6. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
include a low-pass filter having a predetermined time constant, and calculates the disturbance torque estimated value on the basis of the time constant of the low-pass filter, and
decrease the time constant when the initial start operation is determined to have been performed, so as to increase the responsiveness of the driving torque.
7. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
obtain a motor rotation speed or a speed parameter proportional to the motor rotation speed,
use a speed feedback control system that performs a feedback of values on which a moving average based on a predetermined count of samplings is applied to the obtained motor rotation speed or the speed parameter, so as to calculate the disturbance torque estimated value, and
decrease the predetermined count of the samplings when the initial start operation is determined to have been performed.
8. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
cause the motor to generate a vibration damping torque for reducing vibration generated on a vehicle body as a vibration damping control processing, and
in the vibration damping control processing, use a feedback control system to calculate the vibration damping torque, and sets a feedback gain of the feedback control system smaller than the feedback gain just before the stop of the vehicle when the initial start operation is determined to have been performed.
9. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
obtain a motor rotation speed or a speed parameter proportional to the motor rotation speed,
determine that the initial start operation has been performed when an absolute value of the obtained value of the motor rotation speed or the speed parameter increases to equal to or more than a predetermined first rollback determination value and subsequently decreases to equal to or less than a predetermined second rollback determination value, and
decrease the increased responsiveness of the driving torque to equivalent to the responsiveness of the driving torque just before the stop of the vehicle when the initial start operation is determined to have been performed.
10. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
decrease the responsiveness of the driving torque to equivalent to the responsiveness of the driving torque just before the stop of the vehicle after a lapse of a predetermined time period since the initial start operation is determined to have been performed.
11. The control device for the electric vehicle according to claim 1 , wherein the controller is configured to:
obtain a gradient of a road surface on which a vehicle stops, and
increase the responsiveness of the driving torque as the gradient becomes large.
12. A control method for an electric vehicle, the electric vehicle including a motor that generates a driving torque and a controller that controls the motor, the control method for the electric vehicle comprising:
determining, via the controller, whether an initial start operation of a vehicle has been performed by a driver, the initial start operation being not performed with an accelerator operation;
calculating, via the controller, a disturbance torque estimated value necessary for maintaining a vehicle stop state corresponding to a disturbance acting on the vehicle;
performing, via the controller, a control such that the driving torque of the motor converges to the disturbance torque estimated value when the vehicle is determined to be just before stop of the vehicle during running or determined to have undergone the initial start operation; and
increasing, via the controller, a responsiveness of the driving torque of the motor compared with a responsiveness of the driving torque just before the stop of the vehicle when the initial start operation is determined to have been performed.