MRAS-based adaptive speed estimator in PMSM drives

The permanent magnet synchronous motor (PMSM) is increasingly playing an important role in advanced motor drives. An encoder or resolver attached to the shaft of the motor typically supplies the feedbacks required for PMSM torque and speed control. Many advanced motor drives can not tolerate the use of these feedback devices because of reliability concerns in a harsh environment, price, space and weight limitations. In this paper MRAS-based adaptive strategy has been used for speed estimation. In compare to previously developed methods in the literature such as: EKF, sliding mode control, H_infin control, this method consumes less computational time and it is easy to implement in microcontrollers and DSP. In this proposed method the Popov´s criterion is used for adaptive speed estimation. The Popov´s criterion is easier than Lyapunov criterion since it does not need for any predetermined function as it is necessary for Lyapunov criterion. The validity of the MRASbased adaptive strategy has been verified by simulation and experiments