Flux estimation for fault tolerant control of PMSM machines for EPS

Patent metadata

Field	Value
Publication number	US-9985564-B2
Application number	US-201615054554-A
Country	US
Kind code	B2
Filing date	Feb 26, 2016
Priority date	Feb 26, 2016
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

A system for estimating flux linkage in an electric motor includes a flux estimation module that generates estimated flux linkages based on a back electromagnetic force and estimated velocity of the electric motor, the flux linkages having an alpha flux linkage component and a beta flux linkage component, and a velocity estimation module that generates an estimated motor velocity based on the back electromagnetic force and the estimated flux linkages.

First claim

Having thus described the invention, it is claimed:

1. A system for estimating flux linkage in an electric motor, the system comprising:
a flux estimation module that generates estimated flux linkages based on a back electromagnetic force and a first estimated motor velocity of the electric motor, the flux linkages having an alpha flux linkage component and a beta flux linkage component; and
a velocity estimation module that generates a second estimated motor velocity based on the back electromagnetic force and the estimated flux linkages received from the flux estimation module.

2. The system of claim 1 , wherein the flux estimation module includes:
a flux estimation high pass filter module that filters the back electromagnetic force signal, thereby generating a high pass output;
a flux estimation low pass filter module that filters the high pass output thereby generating a low pass output, the flux estimation low pass filter module is a second order filter, the flux estimation low pass filter module may include a plurality of first order filters; and
a quadrature signal signature compensator module that generates the flux linkage based on the low pass output and the estimated motor velocity.

3. The system of claim 2 , the flux estimation low pass filter module and the flux estimation high pass filter module are digitally implemented using a bilinear with prewarping that uses the estimated motor velocity as a critical frequency.

4. The system of claim 2 , wherein the quadrature signal signature compensator module compensates based on a sign of the estimated motor velocity.

5. The system of claim 2 , wherein the flux estimation high pass filter module and the flux estimation low pass filter module operate as functions of the estimated motor velocity.

6. The system of claim 1 , wherein the velocity estimation module includes:
a velocity estimation high pass filter module that filters the back electromagnetic force signal, thereby generating a high pass output; and
a gain and phase compensator module that filters the high pass output thereby generating a low pass output, the gain and phase compensator module is a first order filter.

7. The system of claim 6 , the gain and phase compensator module and the velocity estimation high pass filter module are digitally implemented using a bilinear with prewarping that uses the estimated motor velocity as a critical frequency.

8. The system of claim 1 , wherein the flux estimation module includes:
a flux estimation low pass filter module that filters the back electromagnetic force signal with a second order filter, thereby generating a low pass output;
a flux estimation high pass filter module that filters the low pass output, thereby generating a high pass output; and
a quadrature signal signature compensator module that generates the flux linkage based on the high pass output.

9. The system of claim 8 , the flux estimation low pass filter module and the flux estimation high pass filter module are digitally implemented using a bilinear with prewarping that uses the estimated motor velocity as a critical frequency.

10. The system of claim 1 , wherein the velocity estimation module includes:
a gain and phase module that filters the back electromagnetic force signal thereby generating a low pass output, the gain and phase compensator module is a first order filter; and
a velocity estimation high pass filter module that filters the low pass output, thereby generating a high pass output.

11. The system of claim 10 , the gain and phase compensator module and the velocity estimation high pass filter module are digitally implemented using a bilinear with prewarping that uses the estimated motor velocity as a critical frequency.

12. A method for estimating flux linkage in an electric motor, the method comprising:
generating estimated flux linkages based on a back electromagnetic force and a first estimated motor velocity of the electric motor, the flux linkages having an alpha flux linkage component and a beta flux linkage component; and
generating a second estimated motor velocity based on the back electromagnetic force and the estimated flux linkages that were computed using the first estimated motor velocity.

13. The method of claim 12 , wherein generation of the estimated flux linkages includes:
filtering the back electromagnetic force signal, thereby generating a high pass output;
filtering the high pass output thereby generating a low pass output, the filtering is performed with a second order filter that includes a plurality of first order filters; and
generating the flux linkage based on the low pass output and the estimated motor velocity.

14. The method of claim 13 , wherein the generating the flux linkage based on the low pass output includes compensating based on a sign of the estimated motor velocity.

15. The method of claim 13 , wherein the filtering is based on functions of the estimated motor velocity.

16. The method of claim 13 , wherein the generating the second estimated motor velocity includes:
filtering the back electromagnetic force signal, thereby generating a high pass output; and
filtering the high pass output with a second order filter, thereby generating a low pass output.

17. The method of claim 16 , the filtering is digitally implemented using a bilinear method with prewarping that uses the estimated motor velocity as a critical frequency.

18. The method of claim 13 , wherein the generating the estimated flux linkages includes:
filtering the back electromagnetic force signal with a second order filter, thereby generating a low pass output;
filtering the low pass output, thereby generating a high pass output; and
a quadrature signal signature compensator module that generates the flux linkage based on the high pass output.

19. The method of claim 18 , the filtering is digitally implemented using a bilinear with prewarping that uses the estimated motor velocity as a critical frequency.

20. The method of claim 13 , wherein the generating the second estimated motor velocity includes:
filtering the back electromagnetic force signal with a first order filter, thereby generating a low pass output; and
filtering the low pass output with a high pass filter, thereby generating a high pass output.

Assignees

• Steering Solutions Ip Holding

Inventors

• Pramod Prerit
• Mitra Rakesh

Classifications

• G01P3/44

  for measuring angular speed (G01P3/56 takes precedence) · CPC title

• H02P21/141 Primary

  Flux estimation · CPC title

• G01R33/04

  using the flux-gate principle · CPC title

• G01R33/0385

  in relation with magnetic force measurements (magnetic force microscopes G01Q60/50) · CPC title

• H02P21/18

  Estimation of position or speed · CPC title