Direct torque control system of induction motor based on the fuzzy control technology

A new design of fuzzy direct torque control system for induction motor is introduced, it is based on strategy of modulating the duty cycle to decrease the torque and stator flux ripple. In this design, the hysteresis comparator and the space voltage vector selector of traditional direct torque control system are replaced by fuzzy controller. The fuzzy controller uses a three-input single-output structure, its three input variables are the torque error, flux error and flux angle amplitude, it is responsible for regulating the inverter switch state. The new system can reduce torque and flux ripple, can enhance robustness and adaptability of the system, and can improve the static and dynamic performances of the system. The simulation results on Matlab/Simulink software platform show that the proposed system has better control performance, compared to the conventional direct torque control system.