Improved Sliding-Mode Observer for sensorless control of five-phase induction motor

This paper proposes an improved Sliding-Mode Observer (SMO) for the sensorless control of a five-phase induction motor, which substitutes a sigmod function for the sign function. The conventional SMO is robust against parameter variations and disturbances, however, it has serious chattering problem in the steady state. The proposed method is utilized to reduce the chattering, and the rotor flux is also obtained from SMO for direct field oriented control. The convergence of the improved SMO is analyzed, and sufficient conditions are given to prove the stability. Simulation and experimental results are verified the effectiveness of the proposed method.