Variable-structure position control-a class of fast and robust controllers for synchronous reluctance motor drives

A family of variable structure robust position tracking controller is presented for a three-phase synchronous reluctance motor (SynRM) considering the maximum torque control (MTC) strategy related to this motor. Neglecting the iron losses, the proposed controller is designed including one of the three classes of linear variable structure controller and adaptive input-output feedback linearization (AIOFL) approaches. Foremost, a sliding mode-plus-PI controller is used to obtain the stator current reference signal. For that stage, three classes of a PI-sliding controller are presented. These methods are then compared and its characteristics are specified and the optimum use for any case, determined. The presented position controller is fast response and robust against mechanical parameter uncertainties and load torque disturbance. At Second stage, the proposed sliding mode based AIOFL controller estimates the unknown electrical uncertainties without using sign(.) or sat(.) function. Hence, it reduces chattering or steady state error phenomenon. Finally, the effectiveness and feasibility of the proposed control approach is demonstrated by computer simulation. The results obtained confirm that the desired position reference command is perfectly tracked in spite of motor parameter uncertainties and load torque disturbance.