Research On Parameter Design Optimization Of Half-bridge LLC Resonant Converter

In this paper,for the problem of optimizing the parameter design of the half-bridge LLC resonant converter,the method of optimizing the selection of the inductance K was used in the process of designing the main circuit parameters,according to the equivalent model and working principle of the half-bridge LLC resonant converter.And finally the effect of converter performance optimization was achieved.The main work is now briefly described as follows:1.The topology and working characteristics of the LLC resonant converter were studied.Meanwhile the steady-state characteristics of the converter were analyzed and the Fundamental Harmonic Approximation(FHA)equivalent model was established.The Saber simulation software was used to build a half-bridge LLC resonant converter model.By simulating the working process of the converter,the key waveforms of each device of the converter were obtained,and detailed loss analysis was performed accordingly.At the same time,the DC gain curve was drawn,and the gain characteristics of the converter were analyzed which the influence of quality factor Q and inductance K on the performance of the converter was revealed.2.Based on the analysis of FHA equivalent model,under the premise of zero-voltage turn-on of the switch,the parameter optimization design of the resonant component was analyzed in depth,and the selection of the inductance K was elaborated.Finally,a better design method of the parameters of the half-bridge LLC resonant converter was summarized,and the detailed design flow chart was given after.A 120 W target converter was used as a design example for complete parameter design.3.By simulation and a 120 W experimental prototype,the correctness and effectiveness of the design was verified through testing key waveforms.Through the above work,the following results were obtained:1.Based on the analysis of loss characteristics,the theoretical basis of the optimization design of the resonant cavity parameters of the half-bridge LLC resonant converter was discussed.On this basis,the detailed design process and theoretical basis of the key parameters of the converter cavity were given.The problem of how to select the inductance coefficient was elaborated,and the complete parameter design flow was summarized.2.A 120 W LED drive power prototype was built on the experimental platform.At the same time,the key parameters of the converter were calculated.The comparative simulation and experimental verification were carried out to observe the key waveforms of each part of the converter,and the validity of the parameter design was verified.The experimental results showed that the optimized design not only can meet the requirements of high frequency and high efficiency of LLC resonant converter,but also can reach the power output index.