Torque ripple compensation with feedforward control in motor control systems

1. A motor control system that provides torque ripple compensation when operating in feedforward mode, the motor control system comprising:

a feedforward controller configured to:

receive a first current command corresponding to an input torque command;

receive a second current command corresponding to a torque ripple to be compensated; and

generate a voltage command based on the first current command and the second current command, the voltage command being applied to a motor, wherein generating the voltage command comprises:

determining a first voltage command using the first current command and further based on motor inductance, motor circuit resistance, and motor velocity;

determining a second voltage command using the second current command, and further based on the motor inductance, the motor circuit resistance, and the motor velocity;

determining a third voltage command corresponding to a back-emf of the motor; and

adding the first voltage command, the second voltage command, and the third voltage command.

2. The motor control system of claim 1 , wherein the second current command (Idqp) is for a single order torque ripple.

3. The motor control system of claim 1 , wherein the second current command (Idqp) is for multi-ordered torque ripple, the voltage command compensating the multi-ordered torque ripple simultaneously.

4. A motor control system that provides torque ripple compensation when operating in feedforward mode, the motor control system comprising:

a feedforward controller configured to:

receive a first current command corresponding to an input torque command:

receive a second current command corresponding to a torque ripple to be compensated; and

generate a voltage command based on the first current command and the second current command, the voltage command being applied to a motor, wherein the voltage command (Vdqf) comprises a d-axis component (Vdf) and a q-axis component (Vqf), and generating the voltage command (Vdqf) comprises:

determining a final current command (Idqf) by adding the first current command (Idqr) and the second current command (Idqp), each containing q-axis and d-axis components;

determining the d-axis component (Vdf) of the voltage command using both the d-axis component of the final current command (Idf) and the q-axis component of the final current command (Iqf); and

determining the q-axis component (Vqf) of the voltage command using both the d-axis component of the final current command (Idf) and the q-axis component of the final current command (Iqf), and wherein the voltage command is computed as

V df =( {tilde over (L)} d {tilde over (s)}+{tilde over (R)} ) I df +{tilde over (ω)} e {tilde over (L)} q I qf

V qf =( {tilde over (L)} q {tilde over (s)}+{tilde over (R)} ) I qf −{tilde over (ω)} e {tilde over (L)} q I qf +{tilde over (K)} e {tilde over (ω)} m ,

where L represents inductance of the system, R represents resistance of the system, ω e represents electrical motor velocity, ω m represents motor velocity, K e represents a predetermined value, and s represents a derivative term.

5. A method for torque ripple compensation of a motor control system when operating in feedforward mode, the method comprising:

receiving, by a feedforward controller, a first current command corresponding to an input torque command;

receiving, by the feedforward controller, a second current command corresponding to a torque ripple to be compensated; and

generating, by the feedforward controller, a voltage command based on the first current command and the second current command, the voltage command being applied to a motor, wherein generating the voltage command comprises:

determining a first voltage command using the first current command and further based on motor inductance, motor circuit resistance, and motor velocity;

determining a second voltage command using the second current command, and further based on the motor inductance, the motor circuit resistance, and the motor velocity;

determining a third voltage command corresponding to a back-emf of the motor; and

adding the first voltage command, the second voltage command, and the third voltage command.

6. The method of claim 5 , wherein the second current command (Idqp) is for a single order torque ripple.

7. The method of claim 5 , wherein the second current command (Idqp) is for multi-ordered torque ripple, the voltage command compensating the multi-ordered torque ripple simultaneously.

8. A method for torque ripple compensation of a motor control system when operating in feedforward mode, the method comprising:

receiving, by a feedforward controller, a first current command corresponding to an input torque command;

receiving, by the feedforward controller, a second current command corresponding to a torque ripple to be compensated; and

generating, by the feedforward controller, a voltage command based on the first current command and the second current command, the voltage command being applied to a motor, wherein the voltage command (Vdqf) comprises a d-axis component (Vdf) and a q-axis component (Vqf), and generating the voltage command (Vdqf) comprises:

determining a final current command (Idqf) by adding the first current command (Idqr) and the second current command (Idqp), each containing q-axis and d-axis components;

determining the d-axis component (Vdf) of the voltage command using both the d-axis component of the final current command (Idf) and the q-axis component of the final current command (Iqf); and

determining the q-axis component (Vqf) of the voltage command using both the d-axis component of the final current command (Idf) and the q-axis component of the final current command (Iqf), wherein the voltage command is computed as

V df =( {tilde over (L)} d {tilde over (s)}+{tilde over (R)} ) I df +{tilde over (ω)} e {tilde over (L)} q I qf

V qf =( {tilde over (L)} q {tilde over (s)}+{tilde over (R)} ) I qf −{tilde over (ω)} e {tilde over (L)} q I qf +{tilde over (K)} e {tilde over (ω)} m ,

where L represents inductance of the system, R represents resistance of the system, ω e represents electrical motor velocity, ω m represents motor velocity, K e represents a predetermined value, and s represents a derivative term.

9. A power steering system comprising:

a motor; and

a motor control system configured to operate the motor in feedforward mode, the operating comprising:

receiving a first current command corresponding to an input torque command;

receiving a second current command corresponding to a torque ripple in a circuit of the motor, the torque ripple to be compensated; and

generating a voltage command based on the first current command and the second current command, the voltage command being applied to the motor to cause displacement, the voltage command (Vdgf) comprises a d-axis component (Vdf) and a q-axis component (Vgf), and the voltage command is computed as

V df =( {tilde over (L)} d {tilde over (s)}+{tilde over (R)} ) I df +{tilde over (ω)} e {tilde over (L)} q I qf

V qf =( {tilde over (L)} q {tilde over (s)}+{tilde over (R)} ) I qf −{tilde over (ω)} e {tilde over (L)} q I qf +{tilde over (K)} e {tilde over (ω)} m ,

where I represents current command, L represents inductance of the system, R represents resistance of the system, ω e represents electrical motor velocity, ω m represents motor velocity, K e represents a predetermined value, and s represents a derivative term.

10. The power steering system of claim 9 , wherein generating the voltage command comprises:

determining a first voltage command using the first current command and further based on motor inductance, motor circuit resistance, and motor velocity;

determining a second voltage command using the second current command, and further based on the motor inductance, the motor circuit resistance, and the motor velocity; and

adding the first voltage command and the second voltage command.

11. The power steering system of claim 10 , wherein generating the voltage command further comprises:

determining a third voltage command corresponding to a back-emf of the motor; and

adding first voltage command, the second voltage command, and the third voltage command.

12. The power steering system of claim 9 , wherein generating the voltage command (Vdqf) further comprises:

determining a final current command (Idqf) by adding the first current command (Idqr) and the second current command (Idqp), each containing q-axis and d-axis components;

determining the d-axis component (Vdf) of the voltage command using both the d-axis component of the final current command (Idf) and the q-axis component of the final current command (Iqf); and

determining the q-axis component (Vqf) of the voltage command using both the d-axis component of the final current command (Idf) and the q-axis component of the final current command (Iqf).

13. The power steering system of claim 9 , wherein the second current command (Idqp) is for a single order torque ripple.

14. The power steering system of claim 9 , wherein the second current command (Idqp) is for multi-ordered torque ripple, the voltage command compensating the multi-ordered torque ripple simultaneously.