International Journal of Computer Science Issues

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This paper presents a novel scheme for speed regulation/tracking of Switched Reluctance (SR) motors based on Higher-Order Sliding-Mode technique. In particular, a Second-Order Sliding-Mode Controller (SOSMC) based on Super Twisting algorithm is devel-oped. Owing to the peculiar structural properties of SRM, torque produced by each motor phase is a function of phase current as well as rotor position. More importantly, unlike many other motors the polarity of the phase torque in SR motors is solely determined by the rotor position and is independent of the polarity of the applied voltage or phase current. The proposed controller takes advantage of this property and incorporates a commutation scheme which, at any time instant, selects only those motor phases for the computation of control law, which can contribute torque of the desired polarity at that instant. This feature helps in achieving the desired speed regulation/tracking objective in a power efficient manner as control efforts are applied through selective phases and counterproductive phases are left un-energized. This approach also minimizes the power loss in the motor windings thus reducing the heat generation within the motor. In order to highlight the advantages of Higher-Order Sliding-Mode controllers, a classical First-Order Sliding-Mode controller (FOSMC) is also developed and applied to the same system. The comparison of the two schemes shows much reduced chattering in case of SOSMC. The performance of the proposed SOSMC controller for speed regulation is also compared with that of another sliding mode speed controller published in the literature.