Controller and method for transitioning between control angles

• US 9,154,061 B2
• Filed: 09/30/2013
• Issued: 10/06/2015
• Est. Priority Date: 08/10/2009
• Status: Active Grant

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: Green, Charles E., Marcinkiewicz, Joseph G.
• Primary Examiner(s): Ismail, Shawki S
• Assistant Examiner(s): IMTIAZ, ZOHEB S
• Application Number:
  US14/042,050
• Publication Number:
  US 20140037463A1
• Time in Patent Office: 736 Days
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0025 Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
• CPC Class Codes: H02M 1/0085 Partially controlled bridges
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02P 6/06 Arrangements for speed regulation of a single motor wherein the motor speed is measured and compared with a given physical value so as to adjust the motor speed
• CPC Class Codes: H02P 6/20 Arrangements for starting H02P6/08 takes precedence
• CPC Class Codes: H02P 6/34 Modelling or simulation for control purposes
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A control system for a motor includes an angle determination module, a control module, an angle generation module, and an estimator module. The angle determination module generates an output rotor angle indicative of a desired angle of a rotor of the motor. The control module controls current supplied to the motor based on the output rotor angle. The angle generation module generates a commanded rotor angle in response to a commanded speed. The estimator module determines an estimated rotor angle of the motor. Upon startup of the motor, the angle determination module generates the output rotor angle based on the commanded rotor angle. Upon beginning of a transition period, the angle determination module generates the output rotor angle based on the commanded rotor angle and the estimated rotor angle. Upon ending of the transition period, the angle determination module generates the output rotor angle based on the estimated rotor angle.

Claims

1. A control system for a motor, the control system comprising:

an angle determination module that generates an output rotor angle indicative of a desired angle of a rotor of the motor;

a control module that controls current supplied to the motor based on the output rotor angle;

an angle generation module that generates a commanded rotor angle in response to a commanded speed; and

an estimator module that determines an estimated rotor angle of the motor,

wherein the angle determination module;

upon startup of the motor, generates the output rotor angle based on the commanded rotor angle,

upon beginning of a transition period, generates the output rotor angle based on (i) the commanded rotor angle and (ii) the estimated rotor angle, and

upon ending of the transition period, generates the output rotor angle based on the estimated rotor angle.

2. The control system of claim 1, wherein the transition period begins in response to one or more of (i) an estimated speed of the motor exceeds a predetermined speed, (ii) the commanded speed exceeding a predetermined threshold, (iii) a time period since startup of the motor exceeding a predetermined period, and (iv) convergence of the estimator module.

3. The control system of claim 1, wherein the angle determination module:

upon the startup of the motor, generates the output rotor angle based on the commanded rotor angle independent of the estimated rotor angle, and

upon the ending the transition period, generates the output rotor angle based on the estimated rotor angle independent of the commanded rotor angle.

4. The control system of claim 1, wherein the angle determination module:

during the transition period, generates the output rotor angle based on (i) the estimated rotor angle and (ii) an offset value,

wherein the offset value is based on a difference between (i) the commanded rotor angle at the beginning of the transition period and (ii) the estimated rotor angle at the beginning of the transition period.

5. The control system of claim 4, wherein the angle determination module, during the transition period, generates the output rotor angle based on a sum of (i) the estimated rotor angle and (ii) the offset value.

6. The control system of claim 5, wherein the angle determination module:

at the beginning of the transition period, sets the offset value to the difference between (i) the commanded rotor angle at the beginning of the transition period and (ii) the estimated rotor angle at the beginning of the transition period, and

during the transition period, decreases the offset value to zero.

7. The control system of claim 6, wherein the angle determination module decreases the offset value so that the offset value reaches zero concurrently with the ending of the transition period.

8. The control system of claim 1, wherein the angle determination module, during the transition period, adjusts the output rotor angle to reduce a difference between the output rotor angle and the estimated rotor angle.

9. The control system of claim 8, wherein the angle determination module reduces the difference over time to arrive at zero concurrently with the ending of the transition period.

10. The control system of claim 1, wherein the angle generation module generates the commanded rotor angle by integrating the commanded speed.

11. A refrigeration system comprising:

the control system of claim 1, the motor, and a compressor mechanically driven by the motor.

12. A control method for a motor, the method comprising:

generating an output rotor angle indicative of a desired angle of a rotor of the motor;

controlling current supplied to the motor based on the output rotor angle;

generating a commanded rotor angle in response to a commanded speed; and

determining an estimated rotor angle of the motor,

wherein the generating the output rotor angle includes;

upon startup of the motor, generating the output rotor angle based on the commanded rotor angle,

upon beginning of a transition period, generating the output rotor angle based on (i) the commanded rotor angle and (ii) the estimated rotor angle, and

upon ending of the transition period, generating the output rotor angle based on the estimated rotor angle.

13. The control method of claim 12, wherein the transition period begins in response to one or more of (i) an estimated speed of the motor exceeds a predetermined speed, (ii) the commanded speed exceeding a predetermined threshold, (iii) a time period since startup of the motor exceeding a predetermined period, and (iv) convergence of the rotor angle estimation.

14. The control method of claim 12, wherein the generating the output rotor angle includes:

upon the startup of the motor, generating the output rotor angle based on the commanded rotor angle independent of the estimated rotor angle, and

upon the ending the transition period, generating the output rotor angle based on the estimated rotor angle independent of the commanded rotor angle.

15. The control method of claim 12, wherein the generating the output rotor angle includes:

during the transition period, generating the output rotor angle based on (i) the estimated rotor angle and (ii) an offset value,

wherein the offset value is based on a difference between (i) the commanded rotor angle at the beginning of the transition period and (ii) the estimated rotor angle at the beginning of the transition period.

16. The control method of claim 15, wherein the generating the output rotor angle includes, during the transition period, generating the output rotor angle based on a sum of (i) the estimated rotor angle and (ii) the offset value.

17. The control method of claim 15, wherein the generating the output rotor angle includes:

at the beginning of the transition period, setting the offset value to the difference between (i) the commanded rotor angle at the beginning of the transition period and (ii) the estimated rotor angle at the beginning of the transition period, and

during the transition period, decreasing the offset value to zero.

18. The control method of claim 17, wherein the generating the output rotor angle includes decreasing the offset value so that the offset value reaches zero concurrently with the ending of the transition period.

19. The control method of claim 12, wherein the generating the output rotor angle includes, during the transition period, adjusting the output rotor angle to reduce a difference between the output rotor angle and the estimated rotor angle.

20. The control method of claim 19, wherein the generating the output rotor angle includes reducing the difference over time to arrive at zero concurrently with the ending of the transition period.

21. The control method of claim 12, wherein the generating the output rotor angle includes generating the commanded rotor angle by integrating the commanded speed.

22. The control method of claim 12, further comprising mechanically driving a compressor with the motor.