Patent ID: 6734666
Filing Date: 2004-05-11
Classification: H02K,H02P

Abstract:
A method for determining the angular position of the permanent magnet rotor of a multiphase electric motor including stator coils which are respectively associated with the phases of this motor, each stator coil having a first end and a second end, comprising the steps of:supplying an alternating signal, having a determined frequency, to the first ends of at least two of said stator coils, recuperating measurement signals, in response to said alternating signal, via conductors connected to the second ends of said at least two stator coils, and supplying the measurement signals to electronic processing means, the measurement signals having a periodic amplitude modulation due to a periodic variation in the effective inductance of the corresponding coil as a function of the rotor's angular position, two measurement signals, coming from two different phases of the motor, thus having envelopes of corresponding amplitude modulations which are phase-shifted, extracting, by said electronic processing means, from each recuperated measurement signal a corresponding one of said envelopes of amplitude modulation, and using at least two of said phase-shifted envelopes for determining said rotor's angular position as a function of said periodic amplitude modulation of each measurement signal.