Sliding mode control of induction motor with fuzzy logic observer

Due to the rapid and large amplitude changes of the current and voltage on the load, the controller will generate oscillations around the sliding mode surfaces (chattering) damaging the actuators, thus in order to reduce the load. For this phenomenon, the Relay function has been suggested to be used instead of the classical sign function. On the other hand, when the parameter of the nonlinear object changes with time, the problem of keeping the speed constant when the load changes is difficult, so an adaptive observer using fuzzy logic control is designed to estimate motor speed which is necessary to increase the stability of the controller. From MATLAB/Simulink simulation and experimentation by OPAL_RT device (OPAL-RT has delivered eFPGASIM, the industry's most powerful and intuitive FPGA-based real-time solution) for the three-phase asynchronous induction motor 1-hp, 150-rad/s with a three-phase three-level cascaded inverter, the results show the estimated speed and the good tracking speed according to the value set at a frequency varying from the lowest 10 rad/s to the highest 150 rad/s, and the system remains stable when the stator and rotor resistance changes up to 1.5 times the initial value in the presence of noise. The stability of the suggested algorithm, which requires little memory and produces low output voltages and currents (total harmonic distortion) with high harmonic component. The SMC laws are obtained in the sense of the Lyapunov stability theorem. Therefore, the stability, robustness and tracking control features are guaranteed, and the system is stable even when noise enters in the system.