MODELLING AND SIMULATION OF DCIDC CONVERTER

Abstract

The SMPS are used for many applications where regulated DC is required e.g. office equipment, spacecraft power systems, laptop computers, cordless phone etc. because of its high efficiency and high energy density. Though linear power supply can serve the purpose. The disadvantage with linear power supply is their bulkiness and poor efficiency. They got work at high frequency. Earlier AC to, DC conversion was achieved using Motor-Generator (MG) sets, Mercury-arc rectifiers, Cascade converter, Rotary Converters, thyratrons. The disadvantages of these are bulkiness and its poor regulation. To overcome these limitations switch mode power supply are in use. Full bridge dc/dc converter topology . is extensively applied in medium to high power conversion. In a power level up to 3 kW, the full bridge converter now employs MOSFET switches. High efficiency, high power density, high reliability and low EMI are some of the most desirable features in these applications, particularly for computer and telecom systems. To achieve these features, soft switching techniques are normally employed. Various types of soft switching topology are reviewed in the literature review. However, the conventional soft switching full bridge converter topologies would either lose the soft switching at some operating conditions, or become rather complex in design and implementation for a few4dlo watts applications. In this dissertation a novel zero voltage switching dc/dc full bridge converter topology is presented and analyzed. The proposed topology employs phase- shift at the rectifier section and does not employ any passive component. However; the advantage of the proposed topology is significant: it achieves soft switching independent of line and load conditions. Experimental and simulation results of a prototype 200 W 100-110 Vdc to 50 Vdc converter operating at 10 KHz verify the analysis and design.