Performance study of switching frequency signal injection algorithm in PMSMs for EV propulsion: A comparison in stator and rotor coordinates

This paper studies the performance of the switching frequency signal injection (SFSI) algorithm to estimate the rotor position in permanent magnets synchronous machines (PMSM) intended for electric vehicle (EV) propulsion. A simple and effective demodulation algorithm is proposed to carry out this estimation by using only current measurements. As opposed to recent literature on the subject, the proposed algorithm is not based on the inductance matrix from the high-frequency impedance model of the PMSM, therefore neither voltage sensors nor voltage reconstructions from the inverter switching states are necessary, thus reducing the system complexity. The analytical expressions in both stationary (αβ) and rotating (dq) reference frames are consistently derived. A performance comparison of sensorless control of PMSM in stator and rotor coordinates is carried out considering the dynamics model of a 1,200 Kg mass car. The simulation results obtained through MATLAB^®-SimPowerSystems™ demonstrate the effectiveness of the proposed demodulation algorithm and its superiority in the rotating frame.