SISTEMA DI CONTROLLO E METODO PER FAR FUNZIONARE UN MOTORE A COMMUTAZIONE ELETTRONICA ED UN APPARATO DI LAVAGGIO

A control system for an electronically commutated DC motor having a rotatable assembly and a stationary assembly with a plurality of winding stages. The application of a DC voltage to the winding stages is controlled to provide an effective voltage thereto by commutating the winding stages to apply the DC voltage thereto in sequence to cause rotation of the rotatable assembly. A neutral conductor voltage of the motor is approximated and compared with the back emf of one of the winding stages to obtain an output representing the angular position of the rotatable assembly. The winding stages are commutated in response to this output when a predetermined angular position is reached. The DC voltage applied to the winding stages is pulse width modulated by alternately pulse width modulating first and second drive circuits. The first drive circuit associated with a winding stage which remains on after commutation is pulse width modulated until a predetermined time after commutation and then there is a shift to pulse width modulate the second drive circuit associated with the winding stage which will remain on after the next commutation. A method of operating an electronically commutated motor and a laundering apparatus are also disclosed.