Robust Current Sensor Fault-Tolerant Controller Using Third Order Super-Twisting Sliding Mode Observer and Controller for Induction Motors

This paper aims to enhance the performance and reliability of three-phase IMs in the event of current sensor failures by introducing a robust sensor Fault Tolerant Controller (FTC). The proposed FTC integrates a Third Order Super Twisting Sliding Mode Observer (TOSTSMO) with a novel Direct Field Oriented Control (DFOC) based on a Third Order Super Twisting Sliding Mode Controller (TOSTSMC) for the IM. The first objective is to replace conventional PI controllers with TOSTSMC, which offers superior system dynamics, faster speed and torque responses, and greater robustness against load and rotor resistance variations, outperforming other control methods. TOSTSMC also mitigates the chattering associated with First-Order Sliding Mode Control (FOSMC) while maintaining simplicity, robustness, and accuracy. The second objective is to enhance the Super-Twisting Sliding Mode Observer by incorporating third-order dynamics, which improves estimation accuracy and robustness, particularly in systems with higher-order uncertainties and disturbances. Integrating the TOSTSMO into the proposed FTC system enables precise and robust state estimation of the induction machine, even in the presence of current sensor failures. This ensures that the control system can maintain high performance and reliability despite sensor faults. Simulation results, conducted in the MATLAB/Simulink environment, demonstrate the effectiveness of the proposed algorithm.