Sensorless control of switched reluctance machines for low speeds and standstill

Patent metadata

Field	Value
Publication number	US-10193475-B2
Application number	US-201515317487-A
Country	US
Kind code	B2
Filing date	May 18, 2015
Priority date	Jun 25, 2014
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A method for determining rotor position of a switched reluctance (SR) machine having a rotor and a stator is provided. The method may include injecting a test pulse into one or more idle phases of the SR machine, determining a decoupled flux value based at least partially on a total flux value corresponding to the test pulse and a mutual flux value, and determining the rotor position based at least partially on the decoupled flux value.

First claim

The invention claimed is:

1. A method for determining rotor position of a sensorless control of a switched reluctance (SR) machine having a rotor and a stator at standstill or low speed, comprising:
injecting a test pulse into one or more idle phases of the SR machine;
determining a decoupled flux value based at least partially on a total flux value corresponding to the test pulse and a mutual flux value; and
determining the rotor position based at least partially on the decoupled flux value, wherein the test pulse being injected is based at least partially on a measured phase current and rotor position feedback.

2. The method of claim 1 , wherein the test pulse is configured to have a substantially constant current height, the test pulse being injected based at least partially on a measured phase current and rotor position feedback.

3. The method of claim 1 , wherein the total flux value is determined based at least partially on a voltage integration of the test pulse.

4. The method of claim 1 , wherein the mutual flux value is determined based on one or more predefined relationships between mutual flux values, measured phase current values, and rotor position feedback values.

5. The method of claim 1 , wherein the decoupled flux value is determined based at least partially on a difference between the total flux value and the mutual flux value.

6. The method of claim 1 , wherein the rotor position is determined based on one or more predefined relationships between decoupled flux values, measured phase current values, and rotor position values.

7. A sensorless control system for a switched reluctance (SR) machine having a rotor and a stator at standstill or low speed, comprising:
a converter circuit in electrical communication between the stator and a common bus; and
a controller in electrical communication with at least the converter circuit, the controller being configured to inject a test pulse into one or more idle phases of the SR machine, determine a decoupled flux value based at least partially on a total flux value corresponding to the test pulse and a mutual flux value, and determine the rotor position based at least partially on the decoupled flux value,
wherein the test pulse being injected is based at least partially on a measured phase current and rotor position feedback.

8. The control system of claim 7 , wherein the controller is configured to inject the test pulse to have a substantially constant current height.

9. The control system of claim 7 , wherein the controller is configured to determine the mutual flux value by referring to one or more preprogrammed maps defining relationships between mutual flux values, measured phase current values, and rotor position feedback values.

10. The control system of claim 7 , wherein the controller is configured to determine the decoupled flux value by computing a difference between the total flux value and the mutual flux value, and determine the rotor position by referring to one or more preprogrammed maps defining relationships between decoupled flux values, measured phase current values, and rotor position values.

Assignees

• Caterpillar Inc

Inventors

• Han Seok-Hee
• Nino Baron Carlos
• Wai Jackson
• Khalil Ahmed
• Inoa Ernesto
• Gerdes Jesse
• Thorne James Michael

Classifications

• H02P25/08

  Reluctance motors · CPC title

• H02P25/089

  Sensorless control (direct torque control H02P23/30) · CPC title

• H02P6/185 Primary

  using inductance sensing, e.g. pulse excitation · CPC title

• H02P6/18

  without separate position detecting elements · CPC title

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title