A Novel Method of Estimating Stator Resistance for an F-MRAS based Speed Sensorless Vector Controlled Switched Reluctance Motor Drive

Abstract

This paper discusses the unipolar excitation-based speed sensorless vector controlled SRM drive. The use of mechanical speed sensor or direct position/speed sensors have few concerns in terms of cost, reliability, compactness, environmental issues a few to mention. Therefore, for speed control of SRM, we necessary require some estimation strategy which estimates the speed/position satisfactorily and with ease. In this paper, F-MRAS (Flux based Model Reference Adaptive System) speed is used for estimating the speed for a unipolar vector controlled SRM drive. The speed estimator implemented for vector controlled SRM drive is selected because of its simplicity, no look up table requirement, and no external circuitry requirement for diagnostic pulses injection for determination of rotor position as is required by injection-based speed estimators. The speed estimator is dependent on stator resistance of the machine. For making the speed estimator robust to stator resistance variations, online estimation of the resistance and compensation is best alternative. In this paper a novel stator resistance estimator is proposed which estimates the stator resistance on-line. The existing speed estimator in conjunction with the proposed resistance estimator performs well in all the four quadrants of operation. The speed sensorless SRM drive has been extensively simulated in MATLAB/SIMULINK. Also, the results are verified experimentally.