Sensorless Control of PMSM using Fractional Order SMC and Extended Kalman Observer

In this paper is presented a type of sensorless control system for the rotor speed of a Permanent Magnet Synchronous Motor (PMSM). The control system is Field Oriented Control (FOC) type but the classical PI speed controller is replaced with a Fractional Order - Sliding Mode Control (FO-SMC) speed controller. Based on the fractional calculus, if the controller order is not integer and, starting from the synthesis equations of a SMC-type controller, the equations of a FO-SMC speed controller are synthesized. The disturbances acting on the control system are modeled by their covariance matrices. With these, for rotor speed estimation of PMSM is used an Extended Kalman Filter (EKF) observer. The mathematical models of the PMSM, of the SMC and FO-SMC controllers, of the EKF observer, as well as the numerical simulations achieved in Matlab/Simulink are presented herein. Furthere, are presented the superior performance of the FO-SMC-type controller for the control of both rotor speed and position of the PMSM in comparison with the performance of the control system with SMC-type controller. These is due to the fact that in the the design of the controllers are used higher number of parameters due to the fractional order differential calculus.