Research On Magnetic Component Of Interleaved&Magnetic Integrated LLC Resonant Converter

In order to improve power density of interleaved LLC resonant converter and realize its current sharing characteristics,this paper takes magnetic component as the main research object and carries out optimal design of coupled inductor and transformer.Firstly,magnetic integration of resonant inductors in two phase interleaved LLC resonant converter is presented.The “EIE” type coupling inductor has more advantages than traditional “EE” and “EI” coupling inductor because of its special structure,such as high coupling coefficient,uniform distribution of magnetic pressure,and small loss of winding.In this paper,considering air gap diffusion flux and air reluctance outside windings,optimized magnetic circuit model is established.And coupling inductor is designed by determining coupling coefficient.The Ansys Software simulation and experiment show that the structure is beneficial to realize current sharing characteristics and improve overall efficiency of interleaved LLC resonant converter.Unlike ordinary transformers,the transformer in LLC resonant converter needs to realize a transformer and an inductor simultaneously.In this paper,by analyzing maximum magnetic flux density of the transformer in the LLC resonant converter,a transformer design method is proposed for the interleaved LLC resonant converter,including core selection,coil design,air gap calculation and high frequency loss calculation.Then the rationality and reality of the method are verified by simulation and a concrete example.The comparison with traditional design transformer shows the superiority of the proposed transformer design method.Finally,according to the design parameters of interleaved LLC resonant converter,the feasibility is verified by saber simulation.Then the experimental platform is built with the coupled inductor model and the designed transformer,and the correctness of theory is verified by experiment.