Switched reluctance motor control system

Patent metadata

Field	Value
Publication number	US-10897217-B2
Application number	US-201816107623-A
Country	US
Kind code	B2
Filing date	Aug 21, 2018
Priority date	Aug 21, 2018
Publication date	Jan 19, 2021
Grant date	Jan 19, 2021

Abstract

A device may receive a current measurement of a motor identifying a plurality of component currents associated with a plurality of phases. The device may determine a position estimate for the motor based on the plurality of component currents associated with the plurality of phases. The device may control the motor based on the plurality of component currents.

First claim

What is claimed is:

1. A switched reluctance motor control system, comprising:
a memory; and
one or more processors configured to:
cause a current to be provided to a switched reluctance motor based on an application of a priming voltage to the switched reluctance motor;
determine a plurality of component currents associated with a plurality of motor phases based on the current provided to the switched reluctance motor;
determine that a first component current, of the plurality of component currents, is equal to a second component current of the plurality of component currents;
determine an initial position of a rotor of the switched reluctance motor based on whether a third component, of the plurality of component currents, is greater than or less than the first component current and the second component current and based on a time measurement of a time between causing the current to be provided to the switched reluctance motor and determining that the first component current is equal to the second component current; and
control the switched reluctance motor based on the initial position of the rotor of the switched reluctance motor.

2. The switched reluctance motor control system of claim 1 , wherein the one or more processors are configured to determine the initial position without receiving information identifying a position measurement or a speed measurement.

3. The switched reluctance motor control system of claim 1 , wherein the switched reluctance motor is included in a machine.

4. The switched reluctance motor control system of claim 1 , wherein the one or more processors when causing the current to provided, are configured to:
cause an inverter of the switched reluctance motor to provide the current.

5. The switched reluctance motor control system of claim 1 , wherein the time measurement is less than 0.01 seconds.

6. The switched reluctance motor control system of claim 1 , wherein the time measurement is less than 0.005 seconds.

7. The switched reluctance motor control system of claim 1 , wherein the time measurement is less than 0.001 seconds.

8. The switched reluctance motor control system of claim 1 , wherein the initial position is determined further based on a speed of the switched reluctance motor.

9. A method for controlling a switched reluctance motor, comprising:
receiving, by a device, a current measurement of the switched reluctance motor identifying a plurality of component currents associated with a plurality of motor phases;
determining, by the device, that a first component current, of the plurality of component currents, is equal to a second component current of the plurality of component currents;
determining, by the device, an initial position associated with the switched reluctance motor based on whether a third component, of the plurality of component currents, is greater than or less than the first component current and the second component current and based on a time measurement of a time between a current being provided to the switched reluctance motor and determining that the first component current is equal to the second component current; and
controlling the switched reluctance motor based on the initial position associated with switched reluctance motor.

10. The method of claim 9 , wherein determining that the first component current is equal to the second component current comprises:
determining a sign change of a difference between the first component current and the second component current; and
determining that the first component current is equal to the second component current based on determining the sign change of the difference between the first component current and the second component current.

11. The method of claim 9 , wherein the initial position associated with the switched reluctance motor is determined further based on an engine speed of an engine coupled to the switched reluctance motor.

12. The method of claim 9 , wherein the plurality of motor phases is associated with a pulse width modulation scheme.

13. A machine, comprising:
a motor including a stator and a rotor;
an inverter coupled to the motor; and
a controller configured to:
cause the inverter to provide a current associated with a plurality of phases to the motor and associated with providing a priming voltage to the motor,
wherein the current is modulated based on back electromotive force (EMF) associated with the motor;

determine, based on causing the inverter to provide the current, a plurality of component currents corresponding to the plurality of phases,
wherein the plurality of component currents include a first component current a second component current, and a third component current;

determine whether the first component current is greater than or less than one or more of the second component current or the third component current;

determine an initial position estimate associated with the motor based on whether the first component current is greater than or less than one or more of the second component current or the third component current and based on a time measurement of a time between the current being provided by the inverter and a determination of an equivalency associated with one or more of the first component current, the second component current, or the third component current; and
control the inverter and the motor using at least one command signal based on the initial position estimate.

14. The machine of claim 13 , wherein the motor is a switched reluctance motor.

15. The machine of claim 13 , wherein the initial position estimate is an angular position estimate.

16. The machine of claim 15 , wherein the angular position estimate is 60 degrees, 120 degrees, 180 degrees, 240 degrees, 300 degrees, or 360 degrees.

17. The machine of claim 13 ,
wherein the controller is further configured to:
determine that the second component current is equal to the third component current, and

wherein, when determining whether the first component current is greater than or less than one or more of the second component current or the third component current, the controller is configured to:
determine whether the first component current is greater than or less than the second component current and the third component current.

18. The machine of claim 17 , wherein, when determining that the second component current is equal to the third component current, the controller is configured to:
determine a sign change of a difference between the second component current and the third component current; and
determine that the second component current is equal to the third component current based on determining the sign change of the difference between the second component current and the third component current.

19. The machine of claim 13 , wherein the initial position estimate is determined further based on an engine speed of an engine coupled to the motor.

20. The machine of claim 13 , wherein the initial position estimate is determined further based on a speed of the motor.

Assignees

• Caterpillar Inc

Inventors

• Khalil Ahmed
• Han Sam
• Thorne James
• Gerdes Jesse
• Wai Jackson
• Nino Baron Carlos
• Abdul Sajan

Classifications

• H02P2203/03

  Determination of the rotor position, e.g. initial rotor position, during standstill or low speed operation · CPC title

• H02P2203/01

  Motor rotor position determination based on the detected or calculated phase inductance, e.g. for a Switched Reluctance Motor · CPC title

• H02P6/18

  without separate position detecting elements · CPC title

• H02P6/182 Primary

  using back-emf in windings · CPC title

• H02P25/089 Primary

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