A wavelet based multi-resolution controller for sensorless position control of PM synchronous motors at low speed

This paper presents an application of a wavelet-based multi-resolution PID controller, for sensorless control of PM synchronous motor (PMSM). The procedure uses high-frequency injection. In this proposed controller, the wavelet package is used to decompose the error signal between actual and command signals into different frequency ranges. Consequently, a better estimation of position and speed is obtained. Moreover, a significant decrease in the noise caused by high-frequency injection can achieved. The performance of this system was evaluated in both simulation and laboratory experiments. The complete control system including the proposed wavelet controller was implemented in real time using the dSpace along with a laboratory scale 250-W, 10-pole PMSM. For demonstration of the advantages of the proposed controller, results obtained from this method were compared with the conventional PI controller.