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