Method and apparatus for detecting rotor magnetic pole position in a single-phase BLDC motor

Patent metadata

Field	Value
Publication number	US-11283379-B2
Application number	US-202016903807-A
Country	US
Kind code	B2
Filing date	Jun 17, 2020
Priority date	Aug 22, 2019
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

A method and an apparatus may detect a rotor magnetic pole of a single-phase BLDC motor. The method and apparatus may quickly and precisely initially drive the single-phase BLDC motor by detecting a position of a magnetic pole of a rotor adjacent to a stator by applying a high frequency voltage to the single-phase BLDC motor and analyzing a magnitude of a flowing current.

First claim

What is claimed is:

1. A method for detecting information of a single-phase BLDC (brushless direct current) motor, the method comprising:
applying a high frequency voltage to a single-phase BLDC motor;
eliminating, by a high frequency eliminator, a high frequency component of a current flowing in the single-phase BLDC motor;

determining a fluctuation direction of a magnitude of the current over time;
determining a magnetic pole of a stator of the motor; and
detecting a position of a magnetic pole of a rotor of the motor adjacent to the stator based on the magnetic pole of the stator, the determined fluctuation direction and a current flowing direction.

2. The method for detecting information of a single-phase BLDC motor of claim 1 , wherein the detecting of the position comprises:
in response to an increase in the magnitude of the current flowing in a first direction, detecting a magnetic pole of the rotor adjacent to the stator to be different from the magnetic pole of the stator.

3. The method for detecting information of a single-phase BLDC motor of claim 1 , wherein the detecting of the position comprises:
in response to an increase in the magnitude of the current flowing in a second direction, detecting a magnetic pole of the rotor adjacent to the stator to be the same as the magnetic pole of the stator.

4. The method for detecting information of a single-phase BLDC motor of claim 1 , wherein the detecting of the position comprises:
in response to a decrease in the magnitude of the current flowing in a first direction, detecting a magnetic pole of the rotor adjacent to the stator to be same as the magnetic pole of the stator.

5. The method for detecting information of a single-phase BLDC motor of claim 1 , wherein the detecting of the position comprises:
in response to a decrease in the magnitude of the current flowing in a second direction, detecting the magnetic pole of the rotor adjacent to the stator to be different from the magnetic pole of the stator.

6. The method for detecting information of a single-phase BLDC motor of claim 1 , wherein the high frequency eliminator is a filter.

7. The method for detecting information of a single-phase BLDC motor of claim 1 , wherein the high frequency eliminator is a low pass filter.

8. The method for detecting information of a single-phase BLDC motor of claim 1 , wherein the high frequency eliminator is a first order low pass filter.

9. The method for detecting a rotor magnetic pole of a single-phase BLDC motor of claim 1 , wherein the high frequency voltage applied to the single-phase BLDC motor has a frequency of 500 Hz or higher, and the high frequency eliminator is to eliminate a component of the current having a frequency of 500 Hz or higher.

10. An apparatus for detecting information of a single-phase BLDC (brushless direct current) motor, the apparatus comprising:
a high frequency applier configured to apply a high frequency voltage to the single-phase BLDC motor;
a current analyzer configured to eliminate, by a high frequency eliminator, a high frequency component of a current flowing in the single-phase BLDC motor and to determine a fluctuation direction of a magnitude of the current over time; and
a magnetic pole detector configured to detect a position of a magnetic pole of a rotor of the motor adjacent to a stator of the motor based on a magnetic pole of the stator, the determined fluctuation direction and a current flowing direction.

11. The apparatus for detecting information of a single-phase BLDC motor of claim 10 , wherein the magnetic pole detector is configured to:
in response to an increase in the magnitude of the current flowing in a first direction, detect a magnetic pole of the rotor adjacent to the stator to be different from the magnetic pole of the stator.

12. The apparatus for detecting information of a single-phase BLDC motor of claim 10 , wherein the magnetic pole detector is configured to:
in response to an increase in the magnitude of the current flowing in a second direction, detect a magnetic pole of the rotor adjacent to the stator to be the same as the magnetic pole of the stator.

13. The apparatus for detecting information of a single-phase BLDC motor of claim 10 , wherein the magnetic pole detector is configured to:
in response to a decrease in the magnitude of the current flowing in a first direction, detect a magnetic pole of the rotor adjacent to the stator to be same as the magnetic pole of the stator.

14. The apparatus for detecting information of a single-phase BLDC motor of claim 10 , wherein the magnetic pole detector is configured to:
in response to a decrease in the magnitude of the current flowing in a second direction, detect the magnetic pole of the rotor adjacent to the stator to be different from the magnetic pole of the stator.

15. The apparatus for detecting information of a single-phase BLDC motor of claim 10 , wherein the high frequency eliminator is a filter.

16. The apparatus for detecting information of a single-phase BLDC motor of claim 10 , wherein the high frequency eliminator is a first order low pass filter.

17. The apparatus for detecting information of a single-phase BLDC motor of claim 10 , wherein the high frequency voltage applied to the single-phase BLDC motor has a frequency of 500 Hz or higher, and the high frequency eliminator is to eliminate a component of the current having a frequency of 500 Hz or higher.

18. An apparatus for detecting information of a single-phase BLDC (brushless direct current) motor, the apparatus comprising:
a high frequency applier configured to apply a high frequency voltage to a single-phase BLDC motor;
a first order low pass filter to filter a current flowing in the motor;
a measuring device configured to measure the current that passes through the first order low pass filter; and
a current analyzer configured to determine a fluctuation direction of a magnitude of the current over time, based on the measured current.

19. The apparatus for detecting information of a single-phase BLDC motor of claim 18 , comprising:
a magnetic pole detector configured to detect a position of a magnetic pole of a rotor of the motor adjacent to a stator of the motor based on a magnetic pole of the stator, the determined fluctuation direction and a current flowing direction.

Assignees

• Lg Electronics Inc

Inventors

• You Jae Jun
• Jung Hansu
• Kim Jaemin

Classifications

• H02P25/03

  with brushless excitation · CPC title

• H02P6/26

  Arrangements for controlling single phase motors · CPC title

• H02P6/183 Primary

  using an injected high frequency signal · CPC title

• H02P1/465 Primary

  for starting an individual single-phase synchronous motor · CPC title

• H02P6/18

  without separate position detecting elements · CPC title