Method and apparatus for brushless electrical machine control

Patent metadata

Field	Value
Publication number	US-11181582-B2
Application number	US-202016793623-A
Country	US
Kind code	B2
Filing date	Feb 18, 2020
Priority date	Nov 13, 2013
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

A variable reluctance motor load mapping apparatus includes a frame, an interface disposed on the frame configured for mounting a variable reluctance motor, a static load cell mounted to the frame and coupled to the variable reluctance motor, and a controller communicably coupled to the static load cell and the variable reluctance motor, the controller being configured to select at least one motor phase of the variable reluctance motor, energize the at least one motor phase, and receive motor operational data from at least the static load cell for mapping and generating an array of motor operational data look up tables.

First claim

What is claimed is:

1. A variable reluctance motor load mapping apparatus comprising:
a frame;
an interface disposed on the frame configured for mounting a variable reluctance motor;
a static load cell mounted to the frame separate and distinct from the variable reluctance motor and coupled to the variable reluctance motor so as to react motor torque of the variable reluctance motor; and
a controller communicably coupled to the static load cell and the variable reluctance motor, the controller being configured to select at least one motor phase of the variable reluctance motor, energize the at least one motor phase, and receive, from the static load cell, motor operational data from at least a static load cell static reaction of the motor torque of the variable reluctance motor for mapping and generating an array of motor operational data look up tables.

2. The apparatus of claim 1 , wherein the controller is configured to receive motor operational data from the static load cell and the variable reluctance motor where the motor operational data includes at least one of a static motor torque, a respective phase current for each of the at least one respective motor phase and a motor rotor position.

3. The apparatus of claim 1 , wherein the controller is configured to generate from the motor operational data constant torque values as a function of rotor position and phase currents for adjacent motor phases.

4. The apparatus of claim 3 , wherein the controller is configured to generate minimum power values associated with each constant torque value and provide the minimum power values in a look up table.

5. The apparatus of claim 1 , wherein the controller is configured to generate motor operational data look up tables where each motor operational data look up table includes an array of constant torque values and corresponding phase currents for a given rotor position.

6. The apparatus of claim 1 , wherein the controller is configured to, for an array of predetermined rotor positions corresponding to each predetermined rotor position, energize more than one motor phase at an array of predetermined current combinations and receive, from the static load cell, a resultant static torque for each of the predetermined current combinations.

7. The apparatus of claim 6 , wherein the controller is configured to, for each predetermined rotor position and a predetermined first motor phase current, vary an additional motor phase current or any suitable combinations of additional phase currents.

8. The apparatus of claim 6 , wherein the controller is configured to generate torque values from the resultant static torque and map the torque values and associated phase current combinations for each predetermined rotor position to form the array of motor operational data look up tables.

9. A method for characterizing the relationship between torque, current and position of a variable reluctance motor, the method comprising:
coupling a static load cell to an output shaft of a variable reluctance motor;
generating an array of static torques on the output shaft with the variable reluctance motor, the output shaft being held static by the static load cell;
adjusting a rotor position of the variable reluctance motor;
selecting, with a controller, adjacent phases of the variable reluctance motor from all respective motor phases of the variable reluctance motor and energizing the selected adjacent phases; and recording, with the controller, motor data that includes a static torque value, rotor position, and phase currents for the selected adjacent phases of the variable reluctance motor.

10. The method of claim 9 , wherein an array of phase current combinations are recorded for more than one phase for each static torque value in the array of static torques.

11. The method of claim 9 , wherein an array of static torques is generated for each rotor position in an array of rotor positions.

12. The method of claim 11 , further comprising mapping, with the controller, the array of static torques and respective phase current combinations for each rotor position to form a data look up table.

13. The method of claim 9 , further comprising energizing, with the controller, the selected motor phases at an array of predetermined current combinations for an array of predetermined rotor positions and recording resultant static torque values for each of the predetermined current combinations and corresponding rotor positions.

14. A brushless electric machine comprising:
a passive rotor with at least one rotor pole;
a stator with at least one stator pole and a phase coil associated with each of the at least one stator pole;
wherein the phase coil is configured to establish a flux in a magnetic circuit between the rotor and stator where the rotor and stator define a predetermined electric machine form factor; and
a controller configured to control current to each phase coil to generate a predetermined rotor torque, the controller being programmed with at least predetermined constant torque values and related phase current values so that the controller determines the current for each phase coil for the generation of demanded rotor torque based on the predetermined constant torque values and related phase current values.

15. The brushless electric machine of claim 14 , wherein the predetermined constant torque values and related phase current values are empirically generated values.

16. The brushless electric machine of claim 14 , wherein the predetermined constant torque values and related phase current values of the brushless electric machine are generated from system modeling analysis including one of a numerical modeling analysis or finite element analysis.

17. The brushless electric machine of claim 14 , further comprising a variable reluctance motor that is either rotary or linear configuration.

18. The brushless electric machine of claim 14 , further comprising a variable reluctance motor configured for operation in a vacuum environment.

19. The brushless electric machine of claim 14 , wherein the passive rotor is a coil-less and magnet-less rotor.

20. The brushless electric machine of claim 14 , wherein the related phase current values are an array of phase current values so that each phase current vector produces the predetermined constant torque value common to the array of phase current values.

21. The brushless electric machine of claim 14 , wherein the controller is programmed with minimum power values associated with each of the predetermined constant torque values.

22. The brushless electric machine of claim 21 , wherein the predetermined constant torque values and related power values and phase current values are commutative to every electric machine having a similar form factor to the predetermined electric machine form factor.

23. The brushless electric machine of claim 14 , wherein the related phase current values are premeasured current values.

24. The brushless electric machine of claim 14 , wherein the constant torque values and related phase current values form one or more commutation tables relating torque, rotor position and phase current magnitudes of motor phases.

25. A brushless electric machine comprising:
a passive rotor with at least one rotor pole;
a stator with at least one stator pole and a phase coil associated with each of the at least one stator pole;
wherein the phase coil is configured to establish a flux in a magnetic c

Assignees

• Brooks Automation Inc

Inventors

• Moura Jairo T
• Spiker Nathan
• Gawlik Aaron
• Krishnasamy Jayaraman

Classifications

• H02P6/10 Primary

  Arrangements for controlling torque ripple, e.g. providing reduced torque ripple · CPC title

• H02P23/12

  Observer control, e.g. using Luenberger observers or Kalman filters · CPC title

• G01R31/34 Primary

  Testing dynamo-electric machines · CPC title

• H02P23/0031

  implementing a off line learning phase to determine and store useful data for on-line control · CPC title

• G01L3/22

  electrically or magnetically actuated · CPC title