This research investigates Direct Torque Control (DTC) of Induction Motors using Space Vector Pulse Width Modulation (SVPWM) technique. The study addresses critical limitations of conventional DTC systems, particularly high torque and flux ripples that reduce motor efficiency and performance.
The research focuses on integrating SVPWM with DTC to overcome traditional drawbacks. Conventional DTC suffers from variable switching frequency, high torque ripples, and flux distortion, especially at low speeds. The proposed solution employs SVPWM, which offers superior DC bus utilization, reduced harmonic distortion, and improved voltage vector synthesis compared to traditional PWM methods.
The methodology involves developing a comprehensive mathematical model of SVPWM algorithms, including angle determination, sector identification, and switching time distribution. An open-loop induction motor drive model is implemented in MATLAB/Simulink to validate the system performance. The SVPWM technique treats three-phase inverter outputs as vectors in a two-axis plane, decomposing reference vectors into adjacent active vectors with precise dwell times.
Key findings demonstrate that the DTC-SVPWM combination significantly reduces torque and flux ripples while maintaining constant switching frequency. The results show improved waveform quality, reduced harmonic content, smoother voltage transitions, and enhanced steady-state performance. The system successfully generates controlled three-phase voltages with predictable switching losses and eliminates acoustic noise associated with variable frequency operation.