Motor controller having BEMF compensation for noise and/or vibration reduction
Methods and apparatus for compensating for non-sinusoidal BEMF signals in an electrical motor using amplitudes, phases and orders of BEMF harmonic components and amplitude of 1st harmonic of BEMF of the electrical motor. First and second corrective components for vd and vq of the d-q coordinate system for the motor can be generated from amplitudes of the BEMF harmonic components and the angles of the BEMF harmonic components orders of the BEMF harmonic components and amplitude of 1st harmonic of BEMF.
1. A method, comprising:
compensating for non-sinusoidal BEMF signals in an electrical motor by:
receiving ratio of amplitude, phase shift and order of BEMF harmonic components of the electrical motor;
receiving BEMF constant of the electrical motor;
determining the actual amplitude of BEMF and actual amplitudes of the BEMF harmonic components;
determining angles of the BEMF harmonic components from an order of the BEMF harmonic components, an angle from a d-q coordinate system for the motor, and phase shifts of the BEMF harmonic components relative to a fundamental first harmonic;
generating a first corrective component for vd of the d-q coordinate system for the motor from the amplitudes of the BEMF harmonic components and the angles of the BEMF harmonic components; and
generating a second corrective component for vq of the d-q coordinate system for the motor from the amplitudes of the BEMF harmonic components and the angles of the BEMF harmonic components.
2. The method according to claim 1 , further including generating the first corrective component from a cosine of the angles of the BEMF harmonic components.
3. The method according to claim 2 , further including generating the second corrective component from a sine of the angles of the BEMF harmonic components.
4. The method according to claim 1 , wherein determining angles of the BEMF harmonic components further includes a phase shift correction factor for the BEMF harmonic components.
5. The method according to claim 4 , wherein the phase shift correction factor includes compensation for delay in the system.
6. The method according to claim 4 , wherein the phase shift correction factor includes compensation for speed estimation error.
7. The method according to claim 4 , wherein the phase shift correction factor includes compensation for unwanted effects.
8. A system, comprising:
a compensation system having a processor and memory configured to:
compensate for non-sinusoidal BEMF signals in an electrical motor by:
receiving ratio of amplitude, phase shift and order, of BEMF harmonic components of the electrical motor;
receiving BEMF constant of the electrical motor;
determining the actual amplitude of BEMF and actual amplitudes of the BEMF harmonic components;
determining angles of the BEMF harmonic components from an order of the BEMF harmonic components, an angle from a d-q coordinate system for the motor, and phase shifts of the BEMF harmonic components relative to a fundamental first harmonic;
generating a first corrective component for vd of the d-q coordinate system for the motor from the amplitudes of the BEMF harmonic components and the angles of the BEMF harmonic components; and
generating a second corrective component for vq of the d-q coordinate system for the motor from the amplitudes of the BEMF harmonic components and the angles of the BEMF harmonic components.
9. The system according to claim 8 , wherein the processor and memory are further configured for generating the first corrective component from a cosine of the angles of the BEMF harmonic components.
10. The system according to claim 8 , wherein the processor and memory are further configured for generating the second corrective component from a sine of the angles of the BEMF harmonic components.
11. The system according to claim 8 , wherein determining angles of the BEMF harmonic components further includes a phase shift correction factor for the BEMF harmonic components.
12. The system according to claim 11 , wherein the phase shift correction factor includes compensation for delay in the system.
13. The system according to claim 11 , wherein the phase shift correction factor includes compensation for speed estimation error.
14. The system according to claim 11 , wherein the phase shift correction factor includes compensation for unwanted effects.
15. A system, comprising:
an interface configured to connect to an electrical motor; and
a means for compensating for non-sinusoidal BEMF signals in the electrical motor, wherein the means for compensating for non-sinusoidal BEMF signals in the electrical motor is configured for generating a first corrective component for vd of a d-q coordinate system for the motor from amplitudes of BEMF harmonic components and angles of the BEMF harmonic components, and for generating a second corrective component for vq of the d-q coordinate system for the motor from the amplitudes of the BEMF harmonic components and the angles of the BEMF harmonic components.
16. The system according to claim 15 , wherein the means for compensating for non-sinusoidal BEMF on signals in the electrical motor is further configured for generating the first corrective component from a cosine of the angles of the BEMF harmonic components and generating the second corrective component from a sine of the angles of the BEMF harmonic components.
17. The system according to claim 15 , wherein determining angles of the BEMF harmonic components further includes a phase shift correction factor for the BEMF harmonic components.
18. The system according to claim 17 , wherein the phase shift correction factor includes compensation for delay in the system.
19. The system according to claim 17 , wherein the phase shift correction factor includes compensation for speed estimation error.