A sliding mode controller based DTC of 3 level NPC inverter fed induction motor employing space vector modulation technique

This paper presents the space vector modulation (SVM) based direct torque control (DTC) of induction motor fed by a three level neutral point clamped (NPC) inverter. The SVM DTC system avoids the use of the hysteresis controllers and the look up table which are usually used in the classical DTC scheme. A novel sliding mode controller (SMC) is proposed which controls the speed of the induction machine under load torque fluctuations. Performance of the controller is analyzed during the transient and steady state periods. The speed behavior of the system is observed by applying different load torques. The results are compared with that of the conventional PI controller. It is observed that the SMC controllers are robust to parameter variations and can handle non linearities in a better way when compared with a PI controller.