MODELING AND SIMULATION OF THREE PHASE POWER FACTOR CORRECTED ACTIVE RECTIFIER WITH REDUCED SWITCH COUNT

Abstract

The AC—DC converters, also known as rectifiers, are conventionally developed using diodes and thyristors to provide controlled and uncontrolled unidirectional and bidirectional dc power. However, these rectifiers can pollute the AC supply with significant levels of low frequency harmonics, pulsating input current (electromagnetic interference (EMI)), and excessive VAR. With tough regulations and severe economic restraints, the design of a three-phase switching mode rectifier which draws nearly sinusoidal three-phase input currents with unity power factor is very important from the point of view of energy saving and also to satisfy harmonic standards such as IEEE 519 or IEC 1000-3-2. In response to these problems, a significant amount of research has been devoted to the area of pulse width modulation (PWM) rectifiers (i.e., switching-mode interfaces). Current research has been focusing recently on decreasing the number of power semiconductor switches to simplify the circuit and increase its reliability. In the present work, a four switch three-phase active rectifier(reduced .switch topology) is considered. Detailed power circuit analysis for the undertaken topology is presented. The design considerations are detailed. Four high performance control strategies(reduced hysteresis, space vector modulation, direct power modulation, Fuzzy space vector modulation) are diccussed and verified and compared through simulations. The application of the considered four switch three phase topology to the improvement of power quality is investigated. The considered rectifier can also be used for, harmonic current filtering. The feasibility is tested through simulation. A reduced switch count series filter is presented and verified. Finally experimental prototype of the considered four switch three phase rectifier is constructed and tested for reduced hysteresis control scheme.