Washing machine drive using brushless DC motor

摘要

The use of an electronically controlled brushless dc motor drive is intended to refine the operation of a single tub or automatic washing machine (21). The brushless dc motor (M) drives the tub and impeller (23,25) through a mechanical coupling by which the drive can be applied to either or both the components (23,25). A regulator unit (33) is responsive to external command signals and controls motor operation through a power amplifier and switching circuit (31). A rectifier (29) connected to the mains provides the dc supply. A rotor position detector (35) orders the commutation from one motor phase to the next. It contains a circuit for synthesizing the motor neutral point voltage, and comprising this with the counter emf from one of the windings in order to compute the rotor instantaneous angular position. By comparing the position with a reference angle the signal for ordering the commutation sequence and timing is derived.