SIMULATION OF PWM RECTIFIER WITH DC CURRENT LINK

Abstract

Because of advances in solid state power devices and microprocessors, switching power converters are used in more and more modem motor drives to convert and deliver the required energy to the motor. The energy that a switching power converter delivers to a motor is controlled by Pulse Width Modulated (PWM) signals applied to the gates of the power switches. PWM signals are pulse trains with fixed frequency and magnitude and variable pulse width. There is one pulse of fixed magnitude in every PWM period. However, the width of the pulses changes from pulse to pulse according to a modulating signal. When a PWM signal is applied to the gate of a power switch, it causes the turn on and turn off intervals of the switch to change from one PWM period to another PWM period according to the same modulating signal. Simulation analysis of a three phase PWM rectifier with a current link is presented. The PWM technique used to generate the pulses is Space Vector modulation specially developed for a three phase PWM rectifier with a current link. Simulation result of the converter scheme is reported. Computer simulation results for various operating conditions show that the good harmonic attenuation of line current is achieved by using a simple passive LC filter. iii