Method and System for Controlling a Motor

• US 20140015458A1
• Filed: 07/16/2013
• Published: 01/16/2014
• Est. Priority Date: 07/16/2012
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Agency For Science Technology and Research (Government of Singapore)
• Inventors: LIN, Song, BI, Chao
• Granted Patent: US 9,197,144 B2
• Time in Patent Office: Days
• US Class Current: 318/400.03
• CPC Class Codes: G11B 19/2054 Spindle motor power-up sequences
• CPC Class Codes: H02P 6/188 using the voltage difference between the windings H02P6/182 takes precedence
• CPC Class Codes: H02P 6/20 Arrangements for starting H02P6/08 takes precedence

Abstract

A method and system for controlling a motor is provided. In particular, various embodiments of the present disclosure describe a method and system for controlling a spindle motor in a hard disk drive (HDD) A method of controlling a motor is provided, the motor including a 3-phase synchronous motor with three terminals of an electromagnetic winding configuration. The method includes providing an input voltage between two of the terminals and measures a resultant silent terminal voltage at the third terminal, which is thereafter used in determining a rotor position. A corresponding system for controlling a motor is further provided.

Claims

1. A method of controlling a motor, the motor comprising a 3-phase synchronous motor with three terminals of an electromagnetic winding configuration, the method comprising:

providing an input voltage between two of the three terminals of the electromagnetic winding configuration;

measuring a resultant silent terminal voltage at the third terminal of the electromagnetic winding configuration; and

determining a rotor position of the motor based on the measured silent terminal voltage.

2. The method according to claim 1, further comprising obtaining a plurality of silent terminal voltage measurements, comprising:

manipulating a switching circuit coupled to the three terminals of the electromagnetic winding configuration to close an electrical circuit and provide an input voltage between two of the three terminals of the electromagnetic winding configuration according to a plurality of switching combinations; and

measuring a corresponding plurality of silent terminal voltages.

3. The method according to claim 2, further comprising determining a maximum and a minimum value of each of the plurality of silent terminal voltage measurements.

4. The method according to claim 3, further comprising sorting by value the maximum and minimum values of the plurality of silent terminal voltages measurements.

5. The method according to claim 4, further comprising comparing with a comparison table the sorted maximum and minimum values of the plurality of silent terminal voltages measurements;

and determining a rotor position of the motor based on the comparison.

6. The method according to claim 5, further comprising determining the comparison table, comprising:

holding the rotor at a range of fixed positions and obtaining a plurality of baseline silent terminal voltage measurements according to the plurality of switching combinations; and

determining a switching configuration corresponding to a rotor position based on the plurality of baseline silent terminal voltage measurements.

7. The method according to claim 6, wherein the range of fixed positions comprises aligning any one of the North and South poles of a permanent magnet on the rotor with a winding alignment of the stator.

8. The method according to claim 1, further comprising starting the motor based on the determined rotor position, wherein the determined rotor position is an initial rotor position of the motor.

9. The method according to claim 8, wherein starting the motor comprises energizing two terminals of the electromagnetic winding configuration based on the initial rotor position of the motor.

10. A system for controlling a motor comprising a 3-phase synchronous motor with three terminals of an electromagnetic winding configuration, the system comprising:

a voltage source configured to provide an input voltage between two of the three terminals of the electromagnetic winding configuration; and

a rotor position detection module configured to measure a resultant silent terminal voltage at the third terminal of the electromagnetic winding configuration;

wherein the rotor position detection module determines a rotor position based on the measured silent terminal voltage.

11. The system according to claim 10, wherein the rotor position detection module is configured to manipulate a switching circuit coupled to the three terminals of the electromagnetic winding configuration to close an electrical circuit and provide an input voltage between two of the three terminals of the electromagnetic winding configuration according to a plurality of switching combinations;

and to measure a corresponding plurality of silent terminal voltages, in obtaining a plurality of silent terminal voltage measurements.

12. The system according to claim 11, wherein the rotor position detection module is configured to determine a maximum and minimum value of each of the plurality of silent terminal voltage measurements.

13. The system according to claim 12, wherein the rotor position detection module is configured to sort by value the maximum and minimum values of the plurality of silent terminal voltages measurements.

14. The system according to claim 13, wherein the rotor position detection module is configured to compare with a comparison table the sorted maximum and minimum values of the plurality of silent terminal voltages measurements, to determine a rotor position of the motor.

15. The system according to claim 14, wherein the rotor position detection module is configured to:

hold the rotor at a range of fixed positions and obtain a plurality of baseline silent terminal voltage measurements according to the plurality of switching combinations; and

determine a switching configuration corresponding to a rotor position based on the plurality of baseline silent terminal voltage measurements.

16. The system according to claim 15, wherein the range of fixed positions comprises aligning any one of the North and South poles of a permanent magnet on the rotor with a winding alignment of the stator.

17. The system according to claim 10, further comprising a motor control module coupled to receive a rotor position from the rotor position detection module, wherein the motor control module is configured to start the motor based on the received rotor position.

18. The system according to claim 17, wherein the motor control module is configured to start the motor by energizing two terminals of the electromagnetic winding configuration based on the received rotor position of the motor.