Systems and methods for controlling sinusoidally driven motors

Patent metadata

Field	Value
Publication number	US-10511239-B2
Application number	US-201715800675-A
Country	US
Kind code	B2
Filing date	Nov 1, 2017
Priority date	Nov 1, 2017
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

An angle shift compensation system and method for controlling a sinusoidally driven motor to achieve efficient motion and reduced noise. The motor controller uses the angle shift compensation method to monitor the angle shift between a sinusoidal motor control signal configured to drive the motor and a feedback signal received from at least one position detector indicating the position of the motor rotor with respect to the motor stator. In response, the motor controller proportionally adjusts the amplitude of the motor control signal based on the monitored angle shift to maintain the angle shift substantially equal to an angle shift threshold.

First claim

What is claimed is:

1. A motor control system comprising:
a motor having a rotor and a stator and comprising at least one phase;
at least one position detector adapted to detect a position of the rotor with respect to the stator and generate a feedback signal; and
a controller for controlling the motor, wherein for at least one motor phase the controller is adapted to:
drive the motor phase with a sinusoidal motor control signal; receive a feedback signal from the at least one position detector; determine an angle shift between the motor control signal and the feedback signal;
compare the angle shift to an angle shift threshold;
when the angle shift is below the angle shift threshold, decrease an amplitude of the motor control signal;
when the angle shift is above the angle shift threshold, increase the amplitude of the motor control signal;
wherein the controller is further adapted to calibrate the motor control system to determine the angle shift threshold by:
driving the motor phase with no load using a control signal at a set maximum amplitude value,
receiving a feedback signal from the at least one position detector;
determining a calibration angle shift between the motor control signal at the maximum amplitude and the feedback signal; and
determining the angle shift threshold by adding the calibration angle shift to a predetermined minimum angle shift value.

2. The motor control system of claim 1 , wherein the at least one position detector comprises at least one selected from a position sensor, a Hall Effect sensor, a magnetic position sensor, a resolver, an encoder, an optical encoder, a magnetic encoder, a current sense circuit, a voltage sense circuit, a back electromotive force (EMF) sense circuit, and any combinations thereof.

3. The motor control system of claim 1 , wherein the controller is further adapted to maintain the motor control signal at a fixed frequency.

4. The motor control system of claim 3 , wherein on startup of the motor the controller is further adapted to ramp up a frequency of the motor control signal from a startup frequency to the fixed frequency.

5. The motor control system of claim 1 , wherein the controller does not change a frequency of the motor control signal based on the feedback signal from the at least one position detector.

6. The motor control system of claim 1 , wherein the controller is adapted to determine a fixed frequency of the motor control signal according to a reference speed.

7. The motor control system of claim 6 , wherein the controller is further adapted to change the fixed frequency to a new fixed frequency upon receiving a command indicating a new reference speed.

8. The motor control system of claim 7 , wherein the controller changes the fixed frequency by gradually ramping up or ramping down the frequency from the original fixed frequency to the new fixed frequency.

9. The motor control system of claim 1 , wherein the controller is further adapted to determine a new angle shift between the motor control signal and the feedback signal by weighing the determined angle shift with respect to a new angle shift measurement.

10. The motor control system of claim 1 , wherein the controller is adapted to determine the angle shift using a weighted average estimation.

11. The motor control system of claim 1 , wherein the controller proportionally decreases or increases the amplitude of the motor control signal based on the determined angle shift.

12. The motor control system of claim 11 , wherein the controller decreases or increases the amplitude of the motor control signal using at least one of a linear algorithm, a non-linear algorithm, a proportional-Integral (PI) algorithm, a proportional-integral-derivative (PID) algorithm, a fuzzy logic algorithm, or any combinations thereof.

13. The motor control system of claim 1 , wherein the controller is further adapted to generate the motor control signal in response to a command to move the motor.

14. The motor control system of claim 1 , wherein the controller is further adapted to:
generate the motor control signal at a set maximum amplitude value; and
drive the motor phase by decreasing the amplitude of the motor control signal based on the determined angle shift until reaching the angle shift threshold.

15. The motor control system of claim 14 , wherein the maximum amplitude value comprises a predetermined maximum amplitude value.

16. The motor control system of claim 14 , wherein the controller is further adapted to determine the maximum amplitude value based on a previously converged to amplitude.

17. The motor control system of claim 1 , wherein for the at least one motor phase the controller is further adapted to perform a startup sequence comprising:
generate the sinusoidal motor control signal comprising a startup point;
initially drive the motor phase by gradually ramping up voltage until reaching the startup point in the motor control signal; and
drive the motor phase from the startup point according to the sinusoidal motor control signal.

18. The motor control system of claim 1 , wherein for the at least one motor phase the controller is further adapted to perform a startup sequence comprising:
generate the sinusoidal motor control signal comprising a set amplitude and a startup point, wherein the startup point comprises a startup amplitude;
determine a ramping curve with amplitude that increases from an initial amplitude to the startup amplitude;
drive the motor phase according to the ramping curve until reaching the startup point; and
drive the motor phase from the startup point according to the generated sinusoidal motor control signal.

19. The motor control system of claim 18 , wherein the set amplitude value comprises a predetermined amplitude value.

20. The motor control system of claim 18 , wherein the controller is further adapted to determine the set amplitude value based on a previously converged to amplitude.

21. The motor control system of claim 18 , wherein the startup amplitude comprises a predetermined startup amplitude value.

22. The motor control system of claim 18 , wherein the startup amplitude is determined from a detected load.

23. The motor control system of claim 18 , wherein the controller is further adapted to determine the startup point based on previously detected position by the at least one position detector.

24. The motor control system of claim 18 , wherein the startup point defines a startup angle shift in the sinusoidal motor control signal.

25. The motor control system of claim 18 , wherein the ramping curve comprises a function of increasing voltage from the initial amplitude to the startup amplitude during a predetermined time period.

26. The motor control system of claim 18 , wherein the ramping curve comprises at least one of a linear ramping curve, a non-linear ramping curve, a positive logarithmic curve, a negative logarithmic curve, and any combinations thereof.

27. The motor control system of claim 18 , wherein the initial amplitude comprises zero.

28. The motor control system of claim 18 , wherein the initial amplitude comprises a nominal value greater than zero.

29. The motor control system of claim 1 , wherein the angle shift threshold comprises a value greater than zero.

30. The motor control system of claim 1 , wherein the minimum angle

Assignees

• Crestron Electronics Inc

Inventors

• Rivera Luis J
• Campagna Michael
• Slivka Benjamin

Classifications

• E06B9/68

  Operating devices or mechanisms, e.g. with electric drive · CPC title

• E06B2009/6845

  sensing position · CPC title

• H02P2209/11

  Sinusoidal waveform · CPC title

• H02P6/153 Primary

  wherein the commutation is advanced from position signals phase in function of the speed · CPC title

• E06B2009/6809

  Control · CPC title