Patent ID: 6834407
Filing Date: 2004-12-28
Classification: D06F,Y02B

Abstract:
A method for controlling an electronically commutated motor (ECM) for selectively driving an agitator of a clothes washing machine, comprising the steps of:sensing a repetitively localized position of a rotor of the ECM from the outputs of a plurality of Hall sensors positioned to interact with a magnetic field produced by the rotor; determining an agitator position and an agitator direction of rotation from the sensed repetitively localized position of the rotor; calculating an agitator position error from a comparison of an agitator position command and the agitator position; calculating an ECM command current from the agitator position error; selectively gating power transistors, based upon the repetitively localized rotor position, to energize selected motor phases of the ECM connected to the selectively gated power transistors; measuring current flowing through the selectively gated power transistors to the ECM; gating and un-gating the selectively gated power transistors dependent upon whether the measured current is greater than or less than upper and lower current limits related to the ECM command current.