Research of speed sensorless vector control of an induction motor based on model reference adaptive system

In the model reference adaptive system (MRAS) implemented in the two-axis stationary reference frame, the convergence performance is poor due to the cross feedback relationship between the alpha-axis component and beta-axis component of the rotor flux when the discrete-time calculation is operated. In this paper, a MRAS implemented in the synchronous rotating reference frame is proposed to identify the rotor speed of an induction motor. The reference model and adjustable model used in this MRAS scheme are composed of an advanced rotor flux voltage model and rotor flux current model in the synchronous rotating reference frame respectively. Experimental tests have been carried out in order to validate the effectiveness of the proposed scheme. The controller was implemented on a TMS320C32 digital signal processor (DSP). Experimental results show that good tracking capability and fast responses have been achieved.