Patent ID: 7893649
Filing Date: 2011-02-22
Classification: H02P

Abstract:
1. A method for determining the rotor position of an electronically commutated motor equipped with a plurality of stator phases, whose rotor has magnetic axes with different magnetic permeances, comprising the steps of: applying voltage to the stator phases; monitoring resulting phase currents thereby determining the rotor position in a standstill state of the motor; measuring in a first procedure first and second rise times of the phase currents until predetermined limit values are reached in an unsaturated state, and in a second procedure through the use of saturation effects of the rotor iron and/or stator iron; determining an association of a magnetic axis to a stator phase based on the first rise times of the currents in the unsaturated state of the rotor iron; and determining polarity of the rotor based on the second rise times of the currents when current is supplied accompanied by saturation effects.