Method of controlling motor-driven washing machine and control system for the same

• US 7,913,340 B2
• Filed: 08/10/2009
• Issued: 03/29/2011
• Est. Priority Date: 05/15/2002
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Oh, Min Jin, Son, Kweon, Koo, Bon Kwon, Kim, Jong Ho, Hong, Kwon Ki, Bang, Jong Chul, Lee, Woon Yong, Lyu, Jae Cheol, Cho, In Haeng
• Primary Examiner(s): Barr; Michael
• Assistant Examiner(s): Waldbaum; Samuel A
• Application Number:
  US12/461,379
• Publication Number:
  US 20100037400A1
• Time in Patent Office: 596 Days
• Field of Search: 815/8
• US Class Current: 8/158
• CPC Class Codes: D06F 2103/24 Spin speed; Drum movements
• CPC Class Codes: D06F 2105/48 Drum speed
• CPC Class Codes: D06F 33/47 Responding to irregular working conditions, e.g. malfunctioning of pumps safety arrangements D06F37/42
• CPC Class Codes: D06F 34/08 Control circuits or arrangements thereof
• CPC Class Codes: D06F 37/304 Arrangements or adaptations of electric motors
• CPC Class Codes: H02P 3/22 by short-circuit or resistive braking
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A control system for a motor-driven washing machine. The control system includes an electrical motor; a driving unit that applies an input voltage to the motor to drive the motor; a voltmeter that measures a reverse voltage generated by the motor for each predetermined period; and a microprocessor reducing a speed of the motor if the measured reverse voltage is less than or equal to a predetermined voltage level.

Claims

1. A method of controlling a motor-driven washing machine, the method comprising the steps of:

(a) determining whether a current DC voltage of a driving unit driving a motor is less than or equal to a predetermined voltage level for each predetermined period;

(b) measuring a current leading phase angle of the current DC voltage if the current voltage is less than or equal to the predetermined voltage level; and

(c) decreasing the current leading phase angle of the current DC voltage by a first predetermined level if the measured leading phase angle is greater than zero.

2. The method of claim 1, further comprising the steps of:

(d) measuring a current pulse width modulation (PWM) duty if the measured leading phase angle is equal to zero; and

(e) decreasing the current PWM duty by a second predetermined level if the measured PWM duty if greater than zero.

3. The method of claim 2, wherein the first predetermined level is equal to the second predetermined level.

4. The method of claim 2, further comprising the steps of:

(f) determining whether the motor is stopped; and

(g) repeating steps (a) to (e) if it is determined in step (f) that the motor is not stopped.

5. The method of claim 1, further comprising the steps of:

(f) determining whether the motor is stopped; and

(g) repeating steps (a) to (c) if it is determined in step (f) that the motor is not stopped.