Magnetic flux estimate

Patent metadata

Field	Value
Publication number	US-11811343-B2
Application number	US-202117458731-A
Country	US
Kind code	B2
Filing date	Aug 27, 2021
Priority date	Sep 4, 2020
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

Examples include a method for controlling a synchronous motor using a variable speed drive. The motor includes a permanent magnet rotor generating a magnetic flux. The method includes applying a predefined electrical command signal to the motor and estimating a motor speed in response to the applying of the predefined electrical command signal. The method also includes reaching a desired estimated motor speed and, in response to reaching the desired estimated motor speed, estimating a parameter related to the magnetic flux of the permanent magnet rotor. The method further includes recording the estimated parameter.

First claim

The invention claimed is:

1. A method for controlling a synchronous motor using a variable speed drive, the motor comprising a permanent magnet rotor generating a magnetic flux, the method comprising:
when the motor is at rest, applying a predefined electrical command signal to the motor;
estimating a motor speed in response to the applying of the predefined electrical command signal;
iteratively adapting a value of the predefined electrical command signal as a function of an updated motor speed estimation at least until reaching a desired estimated motor speed that indicates that the motor is operating in a stable manner;
waiting from when the predefined electrical command signal is applied when the motor is still at rest until reaching the desired estimated motor speed;
in response to reaching the desired estimated motor speed, estimating a parameter related to the magnetic flux of the permanent magnet rotor, wherein the parameter is the magnetic flux of the permanent magnet rotor;
recording the estimated parameter; and
taking the recorded estimated parameter into account for driving the synchronous motor.

2. The method according to claim 1 , wherein the estimating of the motor speed comprises monitoring motor currents.

3. The method according to claim 1 , wherein the predefined electrical command signal is a predefined voltage signal.

4. The method according to claim 1 , wherein estimating the parameter related to the magnetic flux of the permanent magnet rotor results from adapting a value of the parameter iteratively.

5. The method according to claim 1 , wherein the desired estimated motor speed is within a reference speed range or above a reference speed threshold.

6. The method according to claim 1 , wherein reaching the desired motor speed comprises comparing an estimated motor speed to an expected motor speed.

7. The method according to claim 6 , wherein the desired motor speed is reached when a difference between the estimated motor speed and the expected motor speed starts decreasing or is less than a speed difference threshold.

8. The method according to claim 1 , wherein the estimated parameter is within a reference parameter range.

9. The method according to claim 1 , wherein the predefined electrical command signal has a predefined amplitude and frequency profile.

10. The method according to claim 1 , the method further comprising providing a magnetic flux state diagnostic based on a deviation of the estimated parameter from a predetermined range.

11. A non-transitory computer-readable storage medium comprising instructions which, when executed by a processor, cause the processor to carry out the method of claim 1 .

12. A variable speed drive of a synchronous motor comprising a permanent magnet rotor, the variable speed drive comprising a processor and a memory, the processor being configured to operate according to the method of claim 1 .

13. The method according to claim 4 , wherein the recorded estimated parameter has the value adapted by iterations performed for adapting a value of the parameter, and the recorded estimated parameter is used as the estimated parameter for a next time the predefined electrical command signal is applied after the motor was again at rest.

Assignees

• Schneider Toshiba Inverter Europe Sas

Inventors

• Jebai Al Kassem
• Devos Thomas
• Malrait François

Classifications

• H02P23/14 Primary

  Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage · CPC title

• H02P2207/05

  Synchronous machines, e.g. with permanent magnets or DC excitation · CPC title

• H02P21/14 Primary

  Estimation or adaptation of machine parameters, e.g. flux, current or voltage · CPC title

• H02P1/04 Primary

  Means for controlling progress of starting sequence in dependence upon time or upon current, speed, or other motor parameter · CPC title

• H02K21/18

  having horse-shoe armature cores (with homopolar co-operation H02K21/20) · CPC title