Granted Patent B2

US 12,355,384 · App. 18/269,819 · Granted Jul 8, 2025

Inventors: Jianbin Liang (Hamilton, CA); Berker Bilgin (Welland, CA)

Assignee: Enedym Inc

H02P29/50H02P25/089

Abstract

Claims (60)

1. A system comprising:

a switched reluctance machine comprising:

a shaft;

a rotor mounted to the shaft, the rotor having a plurality of salient rotor poles;

a stator having a plurality of salient stator poles protruding from the stator towards the rotor poles; and

a plurality of electrical coils wound about the stator poles, the plurality of electrical coils including a plurality of separate phase coils defining a plurality of phases of the switched reluctance machine;

a power source;

a power converter coupled to the power source and to the switched reluctance machine; and

a controller;

wherein the controller is configured to:

determine a plurality of potential phase current waveforms for a corresponding phase coil of the switched reluctance machine;

for each potential phase current waveform, determine a cumulative sound pressure level of the switched reluctance machine, the cumulative sound pressure level determined based on a plurality of harmonic sound pressure levels expected to result from the potential phase current waveform;

identify a desired phase current waveform as the potential phase current waveform associated with an optimal cumulative sound pressure level; and

apply the desired phase current waveform to the corresponding phase coil of the switched reluctance machine using the power converter.

2. The system of claim 1 , wherein the controller is configured to determine the desired phase current waveform using an iterative optimization process wherein each iteration of the iterative optimization process comprises:

identifying an iteration-specific potential phase current waveform;

determining a plurality of iteration-specific circumferential orders associated with the iteration-specific potential phase current waveform;

determining a plurality of radial force harmonic magnitudes associated with the iteration-specific potential phase current waveform;

determining a plurality of iteration-specific forcing frequencies associated with the iteration-specific potential phase current waveform; and

determining the cumulative sound pressure level for the iteration-specific potential phase current waveform using the plurality of iteration-specific circumferential orders, the plurality of iteration-specific forcing frequencies and the plurality of radial force harmonic magnitudes.

3. The system of claim 2 , wherein the controller is configured to determine the cumulative sound pressure level by:

identifying a plurality of iteration-specific harmonic sound pressure levels, each iteration-specific harmonic sound pressure level determined based on a combination of one of the iteration-specific circumferential orders, one of the iteration-specific forcing frequencies and one of the radial force harmonic magnitudes;

determining the cumulative sound pressure level as a sum of the plurality of iteration-specific harmonic sound pressure levels.

4. The system of claim 3 , further comprising a non-transitory storage memory having stored therein a look-up table defined based on simulated sound pressure levels associated with particular circumferential orders and particular forcing frequencies, wherein the controller is configured to determine each iteration-specific harmonic sound pressure level using the look-up table.

5. The system of claim 4 , wherein the look-up table is defined during a pre-processing phase, and the pre-processing phase comprises:

determining a plurality of dominant circumferential modes for the switched reluctance machine based on a geometry and pole configuration of the switched reluctance machine;

for each dominant circumferential mode,

determining a natural frequency associated with that dominant circumferential mode;

determining the simulated sound pressure levels associated with that dominant circumferential mode by simulating a resultant sound pressure level corresponding to at least one frequency value proximate to the natural frequency using a vibroacoustic model of the switched reluctance machine; and

storing the simulated sound pressure levels in the look-up table in association with the corresponding dominant circumferential mode and frequency value.

6. The system of claim 5 , wherein the plurality of dominant circumferential modes are determined by:

identifying a number of magnetic poles of the switched reluctance machine as a ratio between a number of stator poles of the switched reluctance machine and a number of phases of the switched reluctance machine; and

identifying the dominant circumferential modes as a function of the number of magnetic poles.

7. The system of claim 6 , wherein for each dominant circumferential mode:

higher-circumferential-order radial force harmonics that excite that dominant circumferential mode due to a sampling effect of the radial force density harmonics are identified; and

the simulated sound pressure levels associated with that dominant circumferential mode are determined to include sound pressure resulting from the identified higher-circumferential-order radial force harmonics.

8. The system of claim 2 , wherein the controller is configured to determine the plurality of iteration-specific forcing frequencies by:

determining a motor speed of the switched reluctance machine;

determining a plurality of iteration-specific temporal orders associated with the iteration-specific potential phase current waveform; and

determining the plurality of iteration-specific forcing frequencies based on the motor speed and the plurality of iteration-specific temporal orders.

9. The system of claim 8 , wherein the controller is configured to determine the plurality of iteration-specific temporal orders by:

determining a radial force waveform associated with the iteration-specific potential phase current waveform; and

calculating the plurality of iteration-specific temporal orders by applying a fast Fourier transform to the radial force waveform.

10. The system of claim 9 , wherein the controller is configured to:

determine a plurality of dominant temporal orders;

determine a subset of dominant iteration-specific temporal orders corresponding to the plurality of dominant temporal orders; and

determine the plurality of iteration-specific forcing frequencies based on the motor speed and the subset of dominant iteration-specific temporal orders.

11. The system of claim 10 , wherein the plurality of dominant temporal orders are predetermined based on a geometry and pole configuration of the switched reluctance machine.

12. The system of claim 11 , wherein the plurality of dominant temporal orders are predetermined by:

identifying a number of strokes in one mechanical revolution as a product of a number of rotor poles of the switched reluctance machine and a number of phases of the switched reluctance machine; and

identifying the dominant temporal orders as a function of the number of strokes.

13. The system of claim 2 , wherein the controller is configured to determine the plurality of iteration-specific circumferential orders by:

determining a radial force waveform associated with the iteration-specific potential phase current waveform; and

calculating the plurality of iteration-specific circumferential orders by applying a fast Fourier transform to the radial force waveform.

14. The system of claim 2 , wherein the controller is configured to determine the plurality of radial force harmonic magnitudes by:

determining a radial force waveform associated with the iteration-specific potential phase current waveform; and

calculating the plurality of radial force harmonic magnitudes by applying a fast Fourier transform to the radial force waveform.

15. The system of claim 13 , wherein the controller is configured to determine the plurality of iteration-specific circumferential orders and the plurality of radial force harmonic magnitudes concurrently by applying the fast Fourier transform to the radial force waveform.

16. The system of claim 13 , wherein the controller is configured to determine the radial force waveform using a dynamic motor drive model based on a motor speed and a DC link voltage of the switched reluctance machine.

17. The system of claim 13 , wherein the controller is configured to determine the radial force waveform based on a motor speed, phase voltages and phase currents of the switched reluctance machine.

Assignments (1)

Continuity (2)

References Cited (28)