Stator-flux-oriented control for threephase induction motors using sliding mode control

Abstract

Most three-phase induction motor controllers in industry usually keep the motor speed constant when loads change. This is very difficult to implement for nonlinear objects. The motor parameters in operation always change according to the conditions of temperature and noises. This paper proposes a new method for controlling the stator-flux-oriented vector for three-phase induction motors basing on sliding mode control. Two sliding mode controllers are designed independently to regulate the motor flux and torque. In addition, the motor reference speed is also estimated to create a third control loop for improving the stability of controllers. Moreover, the chattering issues around the sliding surface are also considered to increase the system robustness. The simulation and experiment results for a cascaded 7-level inverter system have validated the performance of the proposed method.