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Research On Modified Soft-switching Full-bridge Boost Converter

Posted on:2014-01-04Degree:MasterType:Thesis
Country:ChinaCandidate:W A LiFull Text:PDF
GTID:2252330401976787Subject:Circuits and Systems
Abstract/Summary:PDF Full Text Request
This article is based on the project of airborne microwave power module. The purpose is toexplore and research on power converter applied in low volta ge high current input, with highefficiency, high step-up ratio, high power density and high reliability. One kind of full-bridgeboost converter is modified, and a lot of work is done on it.The full-bridge boost converter is formed by the junction of boost converter and full-bridgeconverter. It has the advantage of high voltage gain, isolation between input and output,bi-directional magnetization of transformer. And it draws much attention in health care, newenergy and other areas. But because of the presence of the transformer’s leakage inductance, thecircuit could easily cause a large voltage overshoot, resulting in damage to power devices. Thereare a variety of schemes to address the voltage overshoot and switches’ soft-switching.In this paper, the resonance between transformer’s leakage inductance and capacitance isutilized to achieve switches’ soft-switching, which can not only reduce the adverse effect of theleakage inductance, but also be beneficial to the improvement of conversion efficiency. Thesteady-state operation process, voltage gain characteristics, load characteristics, parameter design,clamping technology, dynamic modeling and close loop design of the soft-switching full-bridgeboost converter is studied, in order to solve the problem of microwave power module’s powersupply. The main research contents and innovations are as follows:1.One full-bridge boost converter is modified to solve the problem of voltage overshootwhen switches are switched off and lack of step-up ratio.2.The steady-state operation, soft-switching conditions, load and gain characteristics ofthe modified converter is analyzed, laying the foundation for fabrication of the converter.3.The parameter design process of the converter is explored. Resonance parameters are thekey to the success of the converter design, limited by the voltage gain, switches’soft-switching and efficiency. This article provides an effective parameter design method.4.The advantage and disadvantage of passive clamp and active clamp is analyzed. Andalso, one multi-resonant converter is investigated.5.The dynamic modeling and closed loop design method is explored, preparing theoreticalbasis for the regulator control.6.The hardware circuit is built to verify correctness of theory and feasibility of converter.
Keywords/Search Tags:Full-bridge Boost Converter, Soft-switching, Resonance, Active Clamping, DynamicModeling
PDF Full Text Request
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