Start-up method and system for permanent magnet synchronous motor drive

• US 20040249596A1
• Filed: 04/20/2004
• Published: 12/09/2004
• Est. Priority Date: 11/12/2001
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Ho, Eddy Ying Yin
• Granted Patent: US 7,066,034 B2
• Time in Patent Office: Days
• US Class Current: 702/106
• CPC Class Codes: H02P 21/18 Estimation of position or speed
• CPC Class Codes: H02P 21/32 Determining the initial rotor position H02P21/34 takes precedence
• CPC Class Codes: H02P 21/34 Arrangements for starting
• CPC Class Codes: H02P 2203/05 Determination of the rotor position by using two different methods and/or motor models
• CPC Class Codes: H02P 6/085 in a bridge configuration
• CPC Class Codes: H02P 6/18 without separate position detecting elements
• CPC Class Codes: H02P 6/181 using different methods depending on the speed

Abstract

A method of determining a rotor angle in a drive control for a motor, comprising the steps of (a) determining a rotor magnetic flux in the motor; (b) estimating the rotor angle on the basis of the rotor magnetic flux; and (c) correcting the estimated rotor angle on the basis of reactive power input to the motor. Step (a) may include the step of non-ideal integration of stator voltage and current values. Step (b) may include the step of correcting phase errors caused by said non-ideal integration via a PLL circuit with phase compensation (F). Step (c) may include the steps of (1) calculating a first reactive power input value as 1.5*We*(C_Lq *I*I) and a second reactive power input value as 1.5*(Vq*id−Vd*iq); (2) determining a difference between said first and second reactive power input values; and (3) applying said difference to the rotor angle estimated in step (b) to obtain a corrected rotor angle. At higher motor frequencies, the estimated rotor angle is based on the rotor magnetic flux. At lower frequencies, it is based on a predetermined motor load model which is used in conjunction with a start-up sequencing logic circuit.

Claims

1. A method of determining a rotor angle in a drive control for a motor, comprising the steps of:

a) estimating the rotor angle; and

b) correcting the estimated rotor angle on the basis of reactive power input to the motor.

2. The method of claim 1, wherein step (a) further comprises the step of (a1) estimating the rotor angle during motor start-up according to a predetermined motor load model in conjunction with a start-up sequencer.

3. The method of claim 2, wherein said load model is representative of motor acceleration torque.

4. The method of claim 3, wherein said model is responsive to load torque current feedback (iq).

5. The method of claim 3, wherein said load model is representative of friction torque.

6. The method of claim 5, wherein said model is responsive to motor frequency (We).

7. The method of claim 2, wherein said step (a1) terminates at an adjustable percentage of rated motor frequency.

8. The method of claim 7, wherein said adjustable percentage is about 10 percent.

9. The method of claim 2, wherein said step (a1) is carried out in open-loop mode and terminates at a transition from open-loop mode to closed-loop mode.

10. A method of determining a rotor angle in a drive control for a motor, comprising the steps of:

a) determining a rotor magnetic flux in the motor; and

b) estimating the rotor angle during motor start-up according to a predetermined motor load model in conjunction with a start-up sequencer;

wherein step (a) includes the step of non-ideal integration of stator voltage and current values.

11. The method of claim 10, wherein said load model is representative of motor acceleration torque.

12. The method of claim 11, wherein said model is responsive to load torque current feedback (iq).

13. The method of claim 11, wherein said load model is representative of friction torque.

14. The method of claim 13, wherein said model is responsive to motor frequency (We).

15. The method of claim 10, wherein said step (b) terminates at an adjustable percentage of rated motor frequency.

16. The method of claim 15, wherein said step (b) terminates at about 10% of rated motor frequency.

17. The method of claim 10, wherein said step (b) is carried out in open-loop mode and terminates at a transition from open-loop mode to closed-loop mode.

18. The method of claim 10, wherein step (a) further includes the step of correcting phase errors caused by said non-ideal integration via a PLL circuit with phase compensation (F).

19. A system for determining a rotor angle in a drive control for a motor, comprising:

a first circuit for estimating a rotor angle; and

a second circuit for correcting the estimated rotor angle on the basis of reactive power input to the motor.

20. The system of claim 19, wherein said first circuit estimates the rotor angle during motor start-up according to a predetermined motor load model in conjunction with a start-up sequencer.

21. The system of claim 20, wherein said load model is representative of motor acceleration torque.

22. The system of claim 21, wherein said model is responsive to load torque current feedback (iq).

23. The system of claim 21, wherein said load model is representative of friction torque.

24. The system of claim 23, wherein said model is responsive to motor frequency (We).

25. The system of claim 20, wherein said estimating step terminates at an adjustable percentage of rated motor frequency.

26. The system of claim 25, wherein said estimating step terminates at about 10% of rated motor frequency.

27. The system of claim 20, wherein said estimating step is carried out in open-loop mode and terminates at a transition from open-loop mode to closed-loop mode.

28. A system for determining a rotor angle in a drive control for a motor, comprising:

a) a first circuit for determining a rotor magnetic flux in the motor; and

b) a second circuit for estimating the rotor angle during motor start-up according to a predetermined motor load model in conjunction with a start-up sequencer;

wherein said first circuit carries out non-ideal integration of stator voltage and current values.

29. The system of claim 28, wherein said load model is representative of motor acceleration torque.

30. The system of claim 29, wherein said model is responsive to load torque current feedback (iq).

31. The system of claim 29, wherein said load model is representative of friction torque.

32. The system of claim 31, wherein said model is responsive to motor frequency (We).

33. The system of claim 28, wherein said estimating step terminates at an adjustable percentage of rated motor frequency.

34. The system of claim 33, wherein said estimating step terminates at about 10% of rated motor frequency.

35. The system of claim 28, wherein said estimating step is carried out in open-loop mode and terminates at a transition from open-loop mode to closed-loop mode.

36. The system of claim 28, wherein said second circuit corrects phase errors caused by said non-ideal integration via a PLL circuit with phase compensation (F).