ELECTRIC MOTOR FEEDFORWARD CONTROL UTILIZING DYNAMIC MOTOR MODEL

• US 20140239860A1
• Filed: 02/26/2014
• Published: 08/28/2014
• Est. Priority Date: 02/26/2013
• Status: Active Grant

• Current Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Inventors: Kleinau, Julie A.
• Granted Patent: US 9,663,139 B2
• Time in Patent Office: Days
• US Class Current: 318/400.14
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: H02P 21/22 Current control, e.g. using a current control loop
• CPC Class Codes: H02P 2207/05 Synchronous machines, e.g. with permanent magnets or DC excitation
• CPC Class Codes: H02P 6/157 wherein the commutation is function of electro-magnetic force [EMF]

Abstract

A motor control system comprising a motor configured to operate at a rotational velocity and a control module in communication with the motor is provided. The control module is configured to receive a torque command indicating a desired amount of torque to be generated by the motor, obtain a rotational velocity of the motor, receive a desired phase advance angle for driving the motor; and generate a voltage command indicating a voltage magnitude to be applied to the motor based on the rotational velocity of the motor, the motor torque command, and the desired phase advance angle by using a plurality of dynamic inverse motor model equations that (i) allow the desired phase advance angle to exceed an impedance angle of the motor and (ii) specify that the voltage magnitude is a function of a voltage magnitude of a previous voltage command.

Claims

1. A motor control system, comprising:

a motor configured to operate at a rotational velocity; and

a control module in communication with the motor, the control module configured to;

receive a torque command indicating a desired amount of torque to be generated by the motor;

obtain a rotational velocity of the motor;

receive a desired phase advance angle for driving the motor; and

generate a voltage command indicating a voltage magnitude to be applied to the motor based on the rotational velocity of the motor, the motor torque command, and the desired phase advance angle by using a plurality of dynamic inverse motor model equations that (i) allow the desired phase advance angle to exceed an impedance angle of the motor and (ii) specify that the voltage magnitude is a function of a voltage magnitude of a previous voltage command.

2. The motor control system of claim 1, wherein the control module is further configured to:

receive a desired amount of regenerative current; and

limit a regenerative current to be generated by the motor to the desired amount of regenerative current by applying the generated voltage command to the motor.

3. The motor control system of claim 1, wherein the control module obtains a rotational velocity of the motor by receiving a rotational position of the motor and computing the rotational velocity based on the rotational position.

4. The motor control system of claim 1, wherein the plurality of equations include:

5. The motor control system of claim 4, wherein the plurality of equations further comprise

6. The motor control system of claim 4, wherein the plurality of equations further comprise V=Sign(V_q)√

{square root over (V_q²+V_d²)}, wherein the control module is further configured to use V=Sign(V_q)√

{square root over (V_q²+V_d²)} to compute the voltage command when the phase advance angle δ

is greater than 90 degrees, wherein Sign(V_q) is a function that outputs a sign of V_q.

7. The motor control system of claim 1, wherein the plurality of equations include:

8. The motor control system of claim 7, wherein the rotor mechanical velocity ω

_m is the rotational velocity of the motor, wherein the electrical velocity ω

_e is calculated by multiplying the mechanical velocity ω

_m by a number of poles of the motor, and dividing a product of the mechanical velocity ω

_m and the number of poles by two.

9. The motor control system of claim 1, wherein the control module is further configured to send the voltage command to the motor to control the motor.

10. The motor control system of claim 1, wherein the control module comprises a non-recursive derivative filter that is configured to calculate derivative terms of the dynamic inverse motor model equations.

11. The motor control system of claim 10, wherein at least two of filter coefficients that the non-recursive derivative filter is configured to use same coefficient values with opposite signs.

12. A method for controlling a motor of an electronic power steering (EPS) system, the method comprising:

receiving a torque command indicating a desired amount of torque to be generated by the motor;

obtaining a rotational velocity of the motor;

receiving a desired phase advance angle for driving the motor; and

generating a voltage command indicating a voltage magnitude to be applied to the motor based on the rotational velocity of the motor, the motor torque command, and the desired phase advance angle by using a plurality of dynamic inverse motor model equations that (i) allow the desired phase advance angle to exceed an impedance angle of the motor and (ii) specify that the voltage magnitude is a function of a voltage magnitude of a previous voltage command.

13. The method of claim 12 further comprising:

receiving a desired amount of regenerative current; and

limiting a regenerative current to be generated by the motor to the desired amount of regenerative current by applying the generated voltage command to the motor.

14. The method of claim 12, wherein the obtaining a rotational velocity of the motor comprises receiving a rotational position of the motor and computing the rotational velocity based on the rotational position.

15. The method of claim 12, wherein the plurality of equations include:

16. The method of claim 15, wherein the plurality of equations further comprise

17. The method of claim 15, wherein the plurality of equations further comprise V=Sign(V_q)√

{square root over (V_q²+V_d²)}, wherein the method further comprises using V=Sign(V_q)√

{square root over (V_q²+V_d²)} to compute the voltage command when the phase advance angle δ

is greater than 90 degrees, wherein Sign(V_q) is a function that outputs a sign of V_q.

18. The method of claim 12, wherein the plurality of equations include:

19. The method of claim 18, wherein the rotor mechanical velocity ω

_m is the rotational velocity of the motor, wherein the electrical velocity ω

_e is calculated by multiplying the mechanical velocity ω

_m by a number of poles of the motor, and dividing a product of the mechanical velocity ω

_m and the number of poles by two.

20. The method of claim 12 further comprising sending the voltage command to the motor to control the motor.