Patent ID: 7443128

Claim:
A method for controlling a synchronous permanent magnet multiple-phase motor, the motor having multiple phases and having a rotor, the method comprising: controlling drive currents supplied to the phases of the motor by turning the drive currents off at a predetermined frequency; measuring, at said predetermined frequency, induced voltages of at least two of the phases of the motor, when the drive currents in said at least two of the phases of the motor are turned off, with a sensitivity sufficient for obtaining significant voltage values at a near-zero speed of the rotor; determining a position and/or a speed of the rotor from said measured induced voltages; filtering the position and/or the speed of the rotor with a state filter to obtain a filtered rotor position and/or a filtered rotor speed; and adjusting the drive currents according to the filtered rotor position and/or the filtered rotor speed.