| Resonant converter has the advantage of higher operation frequency, higher efficiency,lower switching loss, smaller volume, lower EMI noise and lower switching stress comparedwith the PWM converter. Resonance topology is a lot of more phyletic, the LLC resonantconverter has the primary side switch tube easy to realize full load range of ZVS, secondarydiode easy realize ZCS and input voltage range wide, etc. and thus received extensiveattention.This thesis discusses the kinds of soft switch technology and its development trend,series, parallel and series-parallel three traditional soft-switching resonant converter areanalyzed theoretically, and the advantages and disadvantages are summarized. Then, in thetraditional LC resonant converter based on adding a parallel inductance LLC half-bridgeresonance converter in the composition of the work area has carried on the classification,according to the two resonant frequency fw(series-parallel resonant frequency) and fo(seriesresonance frequency), it can be divided into three work area, based on the working principleof the different regions of the in-depth analysis of the work between the two resonancefrequency is obtained LLC half-bridge resonance converter can realize the original side of theswitch tube and vice side of rectifier diode soft switch. Based on FHA(first harmonicapproximation) method for the gain characteristics of the LLC half-birdge resonant converterhas carried on the thorough discussion, and conclusion is deduced a harmonic parametersdesign method. Also analyzes the converter of no load and short circuit characteristic.Based on the above theoretical analysis and design methods, developed a platform basedon L6599LLC half-bridge resonance converter prototype. Through the prototype is tested andthe results are analyzed, the theoretical correction and the feasibility of design method areverified. |
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