IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE) e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 9, Issue 1 Ver. V (Feb. 2014), PP 19-24 www.iosrjournals.org www.iosrjournals.org 19 | Page Simulation of Push-pull Multi-output Quasi-resonant Converter T.Anitha 1 , S.Arulselvi 2 1 (Assistant Professor, Department of Electronics and Instrumentation Engg., Annamalai University ,India) 2 (Professor, Department, of Electronics and Instrumentation Engg., Annamalai University ,India) Abstract : Power supply voltages in digital systems have been reduced considerably in recent years and often digital components requiring different voltages are present in the same board. This has increased the demand for multiple output power distribution systems with tight load regulation. In this paper, a detailed analysis and design of a multi-output push-pull zero voltage switching (ZVS) quasi resonant converter (QRC) has been carried out. Also simulation of multi-output push-pull zero voltage switching (ZVS) quasi resonant converter (QRC) has been carried out using Matlab/SIMULINK software. The proposed converter is suitable for aerospace applications. Keywords: dc-dc converters, push-pull converter, quasi-resonant converters, Zero voltage switching. I. INTRODUCTION Multi-output PWM dc-dc converters are widely used in communications, aerospace and computer systems, as they are usually more compact and less expensive than a collection of single-output converters. Fig.1 shows the schematic of single power converter with multiple outputs, e.g. push-pull converter with multiple secondary windings. In aerospace applications the allowable size and weight are highly restricted to accommodate greater payload. In the effort to increase the power density of power supplies, the switching frequency is pushed to high values which, in PWM converter realizations, normally lead to considerable power loss, high switching stresses, reduced reliability, and acoustic noise. Another significant drawback of the switch-mode operation is the EMI produced due to large di/dt and dv/dt. To overcome these short comings, new families of QRCs are introduced [1]-[2].Few research papers have been presented about the design and implementation of push-pull hard switched and Quasi-resonant converters[3]-[5].Push-pull converters is mainly used for medium and high power applications compared to half-bridge and full-bridge converter. It has wide duty ratio control and it can be used for multi-output applications with low output and input ripple current. This paper presents the design of multi-output push-pull ZVS-QRC. The proposed method reduces the switching losses and size of the converter. It can be used as high-density power supply for aero-space applications. All simulation works are carried out using MATLAB/SIMULINK software. Figure 1 Multiple outputs using single power converter. II. ANALYSIS OF MULTI-OUTPUT PUSH-PULL ZVS QRC The proposed push-pull topology is basically two forward converters connected in anti-phase. An additional two resonant tanks are added in this topology compared to PWM push-pull converter. The resonant