Wavelet filtering for position estimation of permanent magnet machine in carrier signal injection based sensorless control

The estimation of rotor position at low speed is heavily effected by the signal processing used for extracting the high frequency current signal in carrier signal injection based sensorless control algorithm. An appropriate signal processing strategy assures the successful extraction of the required signal used for the position estimation. In this paper, we propose a wavelet based filtering approach capable of extracting the position information even at low values of injection voltage where conventional filters fail to extract the information. The results obtained are compared with 1^st order Butterworth band pass filter.