LEVITATION AND SPEED CONTROL OF BEARINGLESS SWITCHED RELUCTANCE MOTOR USING FUZZY SLIDING MODE CONTROLLER

The bearingless switched reluctance motor (BSRM) is an integrated device of the switched reluctance motor and the magnetic bearings (MBs) with simple structure possessing no mechanical contact and friction. The nonlinear and uncertain nature of BSRM makes the design of controller difficult for steady levitation of rotor and one of the prominent model-free control techniques to tackle such uncertain systems is the sliding mode control (SMC). This paper proposes a control strategy by merging the intelligence of fuzzy logic with SMC, known as fuzzy sliding mode controller (FSMC) to overcome the drawbacks of SMC regarding high control gains and chattering. The proposed controller modifies the signum function of switching control term with fuzzy logic function, to eliminate rotor vibrations (chattering) with assured robust levitation control under load variations and disturbances. The effectiveness of the proposed FSMC is demonstrated through simulation studies using Matlab/Simulink software comparing with the conventional sliding mode controller.