Rotor position detection scheme for synchronous reluctance motor based on current measurements

A rotor position detection scheme which utilizes the characteristics of the synchronous reluctance motor is proposed. In particular, the dependence of the self and mutual inductances on the rotor position is utilized. The motor currents are controlled by a transistor inverter in the manner of hysteresis current control. The inverter switching creates ripples in the phase currents. The rate change of current in the ripples is then detected and converted to a rotor position signal. The proposed scheme is aimed at providing rotor position information particularly at low rotor speed, even at zero rotor speed. Numerical analysis of the rate change of the phase current of the synchronous reluctance motor is also discussed