Position sensorless operation of IPMSM with near PWM switching frequency signal injection

This paper proposes a new position sensorless control method based on the high frequency signal injection. The frequency of the signal is increased up to 2/3 of the switching frequency, and the dynamics of the sensorless control can be improved. Furthermore, the audible noise is reduced conspicuously due to the increased frequency of injected signal. In this method, the rotor position is directly calculated from three successively sampled currents and voltages without any filter. The injected signal comes from three voltage vectors rotating at the stationary reference frame. The 15Hz speed control bandwidth and 300Hz current regulation bandwidth has been demonstrated with the experimental test results.