AN OPTIMIZED HYBRID SPACE VECTOR PULSE WIDTH MODULATION FOR REDUCTION OF TORQUE RIPPLE IN VOLTAGE SOURCE INVERTER FED INDUCTION MOTOR

Abstract

The Pulse Width Modulated adjustable speed drive is popular in many new industrial applications where it desire superior performance. Recent developments in fast switching semiconductor devices have lead to improve the modulated power in three phase voltage source inverter with adjustable voltage and frequency to asynchronous motor. The most commonly used PWM schemes for three phase voltage source inverter to obtain adjustable voltage and frequency are carrier-based sinusoidal PWM and space vector PWM (SVPWM). The hybrid space vector pulse width modulation (HSVPWM) is one of the modified versions of space vector PWM. This thesis aims to design hybrid space vector pulse width modulating technique which is combination of continuous and bus clamping pulse width modulation techniques used in voltage source inverter fed induction motor. In continuous modulation such as Conventional Space Vector Pulse Width Modulating (CSVPWM) technique, both the zero states (0 0 0) V0 and (1 1 1) V7 applied in every sub cycle, but in bus clamping PWM methods uses only one zero state in every sub cycle. This thesis also suggests certain novel switching sequences involving division of active vector time for hybrid space vector based PWM generation in voltage source inverter fed induction motor. These switching techniques implemented in MATLAB simulation and observed improvement in performance of hybrid space vector PWM, resulted in reduction of torque ripples.