Control system for an electronically commuted motor used in a laundering apparatus and method of operating

Abstract From the Canadian patent

Control system for an electronically commutated motor includes circuitry for integrating the back emf of an unenergized motor winding to determine motor rotor position. However integration should not occur on a field collapse voltage which precedes the back emf. A zero-approaching detector enables the integration of the back emf only when a zero-approach occurs at the ending of the field collapse voltage. The integration is also inhibited from being spuriously enabled by zero approaches for a predetermined length of time after commutation and prior to the ending of the field collapse voltage. A system for controlling the average voltage cyclically applied to a load such as an electronically …