PM synchronous motor drive with wavelet controller and fractional order integrator

Permanent magnet synchronous motor (PMSM) is widely used in low and medium power applications with vector control being a standard control technique. The speed controller is essential for obtaining the required drive performance. Proportional plus integral (PI) controllers were traditionally being employed as speed controllers. The performance degradation in the PI controller due to the fixed controller gains is a concern. This paper investigates the application of wavelet multi-resolution (MRW) speed controller for vector control of the PMSM. The MRW controller process the error input with the gains depending on the level of decomposition employed. In order to limit the number of gains, this paper analyzes MRW controller with a single gain constant. A separate fractional order integrator unit which enhances the controller performance with additional flexibility of tuning and also offers better steady state performance of the motor is introduced. The results show improved performance in terms of speed and current responses and also the ease of tuning.