Generalized Discontinuous PWM Based Direct Torque Controlled Induction Motor Drive with a Sliding Mode Speed Controller

This paper presents a generalized discontinuous pulse width modulation (GDPWM) algorithm for sensorless direct torque controlled induction motor drive, which ensures the high-performance operation, both in steady state and transient conditions. In the proposed method, the merits of basic direct torque control transient behavior are maintained, while the steady state operation is improved. As the bus-clamped sequences are being used, the switching losses of the inverter can be reduced. Also this method gives good performance over the conventional space vector strategy in the higher modulation indices. Then a sliding mode speed controller with an integral switching surface is proposed, which is robust under uncertainties caused by parameter variation and load torque disturbances. To validate the proposed method, the simulation results are presented.