APPARATUS AND METHOD OF CONTROLLING SYNCHRONOUS RELUCTANCE MOTOR

• US 20070257633A1
• Filed: 04/27/2007
• Published: 11/08/2007
• Est. Priority Date: 05/04/2006
• Status: Abandoned Application

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Oh, Jae-Yoon, Won, June-Hee, Cheong, Dal-Ho
• Application Number:
  US11/741,228
• Publication Number:
  US 20070257633A1
• Time in Patent Office: Days
• US Class Current: 318/801
• CPC Class Codes: H02P 25/024 controlled by supply frequency
• CPC Class Codes: H02P 25/08 Reluctance motors
• CPC Class Codes: H02P 6/16 Circuit arrangements for detecting position

Abstract

An apparatus for driving a motor includes a rectifier which rectifies input alternating current (AC) power, a power converter which converts the rectified AC power into direct current (DC) power, an inverter which converts the DC power into AC power of a predetermined frequency that drives the motor, a position detector which detects a position of a rotor of the motor with respect to a stator of the motor by detecting a magnetic flux emanating from the rotor, and a controller which controls the inverter to control the driving of the motor according to the detected position of the rotor.

Claims

1. An apparatus for driving a motor, comprising:

a rectifier which rectifies input alternating current (AC) power;

a power converter which converts the rectified AC power into direct current (DC) power;

an inverter which converts the DC power into AC power of a predetermined frequency to drive the motor;

a position detector which detects a position of a rotor of the motor with respect to a stator of the motor by detecting a magnetic flux emanating from the rotor; and

a controller which controls the inverter to control the driving of the motor according to the detected position of the rotor.

2. The apparatus of claim 1, wherein the position detector comprises:

a sensing magnet, placed on a shaft on the rotor, which generates the magnetic flux; and

at least one hall sensor which detects the generated flux to measure a relative location of the sensing magnet.

3. The apparatus of claim 2, wherein the sensing magnet is fixed on the shaft such that its location is fixed with respect to the rotor.

4. The apparatus of claim 2, wherein the at least one hall sensor comprises a plurality of hall sensors placed at 120°

intervals around the stator.

5. The apparatus of claim 2, wherein the at least one hall sensor outputs one of a high and a low signal, depending on whether it senses a magnetic flux from one of an N pole and an S pole of the sensing magnet.

6. The apparatus of claim 2, wherein the at least one hall sensor is placed at a center of a coil axis of the stator, and a center of a magnetic flux vector emanating from the sensing magnet is aligned with a D-axis of the rotor.

7. The apparatus of claim 1, wherein the controller controls the inverter based on a detected position of a D-axis of the rotor.

8. The apparatus of claim 1, wherein the controller comprises a control integrated circuit (IC) which outputs a voltage based on a signal output by the position detector.

9. The apparatus of claim 1, wherein the controller outputs a 120 degree, 2-phase pulse width modulation (PWM) voltage to start the motor.

10. The apparatus of claim 1, wherein a torque of the motor is at a maximum value when an angle between a D-axis of the rotor and a current vector of the motor is approximately 45 degrees.

11. The apparatus of claim 1, wherein the motor is a permanent magnet assisted synchronous reluctance motor.

12. A method of driving a motor, comprising:

rectifying input alternating current (AC) power;

converting the rectified AC power into direct current (DC) power;

converting the DC power into AC power of a predetermined frequency;

detecting a position of a rotor of the motor with respect to a stator of the motor by detecting a magnetic flux emanating from the rotor; and

controlling an inverter to drive the motor according to the detected position of the rotor.

13. The method of claim 12, wherein the inverter is controlled based on a detected position of a D-axis of the rotor.

14. The method of claim 12, wherein a hall sensor is placed at a center of a coil axis of the stator, and a center of a magnetic flux vector emanating from the sensing magnet is aligned with a D-axis of the rotor.