An approach to real-time position estimation at zero and low speed for a PM motor based on saliency

This paper presents a magnetic saliency based position estimation approach for a PM motor fed by a voltage-source PWM inverter. The proposed real-time estimation algorithm detects the motor current harmonics and calculates the inductance matrix including the rotor position information. The position estimation can be performed every period of pulse-width-modulation or carrier cycle. An experimental system using an interior permanent magnet (IPM) synchronous motor has been constructed. Experimental results verify that the position estimation within 10 degrees in electrical angle is obtained at standstill and such an extremely low-speed as 1 r/min by the proposed approach.