Design of Quasi Resonant Boost Converter Using Zero Current Switching With Push Pull Technology

In this project reduced switching losses and high efficiency is proposed for quasi resonant converter. An AC/DC quasi resonant converter with push pull topology is coupled to two distributed boost inductors into a single magnetic core which hereby reducing the circuit volume and the cost are the development targets of switching power supply today. The quasi resonant converter has ideally zero switching losses as it is having a salient feature that the switching devices can be either switched on at zero voltage or switched off at zero current. The boost power factor corrector operates in the transition mode with a constant on time and variable switching frequencies, wherein the quasi resonant valley switching of the switch, decreases the turn on losses and zero current switching(ZCS) of the output diode in order to decrease the switching losses and improving the conversion efficiency. QRC-ZCS has low total harmonic distortion as conducted on the prototype with experimental and simulation results. Keywordspower factor corrector, push pull topology, Quasi resonant (QR) converter, Zero current switching, coupled inductor Introduction-The quasi resonant converter evincing high efficiency is able to control output voltage to a large extent. Due to the inductive character of the load the switching losses are also limited with the help of pulse width modulation through changing the width of pulses in order to control the output voltage, the converters are managebely controlled. System oscillating at a particular frequency with large amplitude is called resonance. The electrical resonance occurs when the impedance is at minimum. The boost converter is a step up power stage non -isolated power stage topology as here the required output is always higher than the input voltage. For a non-pulsating and continuous input current the output diode conducts only for a portion of the switching cycle. The power factor correction is simply defined as the ratio of real power to apparent power. In AC to DC power conversion system of the switching mode the power factor correction technique is used. The basic principle of Turning on the power device for attaining zero current switching (ZCS) is achieved through the transition mode , hence here the coupled inductor is used. Among the three operating modes of a boost power factor corrector which are the transition mode(TM) continuous conduction mode(CCM) and the discontinuous conduction mode(DCM), the transition mode is the best mode for PFC as in this mode the inductance is neither higher nor lower, it has moderate inductance, the turn on losses are reduced due to the quasi-resonant valley switching of the switch which is an added advantage of