Washing control method of direct drive type vibration basket washing machine

摘要

PROBLEM TO BE SOLVED: To restrain the abrupt change of a turning force of a motor for preventing vibration impact in a period of converting the forward and backward driving directions of a motor in the forward and backward driving of a washing machine by PWM modulating simultaneously gate driving signals applied to the upper and lower side switching element of an inverter part. SOLUTION: Whether or not the backward rotation Mr and forward rotation Mc of a motor M1 coincide with each other is discerned before driving the motor M1. When these rotations do no coincide with each other, the rotational frequency per minute of the motor is sensed by modulation and buffer parts 12 to determine first and second duty cycles Dr1, Dr2 in the early period. When the rotational direction is changed to provide Mr=Mc after PWM duty cycle is set to the first duty cycle Dr1, and demagnetization is applied properly for the rise gradient of driving electric current, the PWM duty cycle is set to the second duty cycle Dr2. Thereafter, when the rotational speed of the motor M1 reaches a fixed speed, the motor M1 is once stopped and converted to the rotation Mr in the reverse direction.