An Approach of Improving the Performance of AC-DC Boost, SEPIC and Ćuk Converter

Abstract

A new topology of single- phase AC-DC converter using Boost, SEPIC and Ćuk converter with low input current THD and high input power factor are proposed. Instead of using a bridge rectifier with two diodes and two switches, or using a single phase rectifier followed by AC-DC converter, the input is chopped at high frequency during positive and negative cycles by a single switch to get step-up AC-DC conversion. Total Harmonic Distortion (THD) of the input current of the proposed circuit with small input current filter is low. Input power factor and the efficiency of conversion of the circuit are high. Feedback control strategy for PFC is used with proposed converters to improve the input power factor and to keep the input current THD within prescribed IEEE limits. In this research work a new family of bridgeless Single phase AC-D CSEPIC Boost and Ćuk Converter with improved efficiency, power factor than conventional converter is proposed. Conventional AC-DC converter suffers from demerits like usage of rectifier bridge, high diode loss in bridge, low efficiency, low power factor, high THD in input current. Proposed converter reduces harmonic contamination in power lines; improve transmission efficiency along with power factor correction. Because of the high frequency switching, the power factor of the circuit is inherently corrected and it requires a small filter to make the input current near sinusoidal with limited THD. The significant improvement in THD makes the circuit a suitable choice in applications needing AC-DC conversion with power conditioning. The circuit of Boost, SEPIC and Ćuk exhibits such better performances than conventional AC-DC Boost, SEPIC and Ćuk converter with variable loads at constant frequency switching with no additional control circuits. Closed loop technique applied to the bridgeless proposed converters to make the results more precise. Addition of feedback controller reduced input current THD significantly at input AC mains along with power factor correction (near unity power factor).The efficiency of the circuit is also satisfactory. Analysis and simulation results of the circuit are obtained by using PSIM 9.11 environment. The main advantages of these new AC-DC converters are its superior power quality over conventional AC-DC converters.