Implementation and Experimental Validation of a Real-Time Discontinuous PWM Technique for VSI Fed IM Drives

Adjustable speed drive system requires variable voltage and frequency supply which is invariably obtained from a three-phase voltage source inverter (VSI). A number of Pulse Width Modulation (PWM) schemes are used to obtain variable voltage and frequency supply from an inverter. The most widely used PWM schemes for a three-phase VSI are carrier-based sinusoidal PWM and space vector PWM (SVPWM). This paper develops discontinuous PWM (DPWM) techniques for a voltage source inverter (VSI). Performance is evaluated in terms of total harmonic distortion (THD) in the output phase voltages. A significant reduction in switching losses is observed by adopting the proposed PWM schemes. The simulation and experimental results are provided to validate the concept.