Research And Implementation Of A Hybrid Bridge LLC Resonant Converter

With the development of modern industry,power electronics technology as a cross-cutting field of power,electronics and control,the key technologies are quietly and ceaselessly new.As one of the research hotspots in the field of power electronics,power converter is widely used in every corner of industrial,military and daily life.For example,aviation DC power supply system,communication power supply,uninterruptible power supply,electric vehicle charging pile,laptop adapter,etc.Starting from the power main circuit topology of the basic LLC resonant converter,the circuit topology is derived from the interleaved parallel technology and the magnetic integration technology.A hybrid bridge type dual output LLC resonant converter circuit topology is presented in this paper.While keeping the excellent soft-switching,high efficiency,low EMI and wide input voltage range of the traditional LLC resonant converter,the number of power transistors is reduced as much as possible,and the dual-channel power output is realized.Thus,the power density of the whole machine is improved.The topology adopts simplified control mode and the fundamental approximation method is used to model the circuit and analyze the working principle of steady state.The complete circuit parameter design is analyzed.The main research work is as follows:1.The operating modes of the main circuit of the basic LLC resonant converter are analyzed under different operating frequencies and resonant frequencies.The mathematical models of each part of the basic LLC resonant converter are established.2.The working principles of two kinds of staggered parallel LLC resonant converters are analyzed,and the characteristics of their circuits are compared.Two kinds of interleaved parallel LLC resonant converters are simulated by Matlab/Simulink.It is concluded that the parallel LLC resonant converter with input series and output is more suitable for high voltage input environment.The output voltage ripple of the interleaved LLC resonant converter is compared with the output voltage ripple of the basic LLC resonant converter under the same parameters,and the principle of output voltage ripple cancellation is analyzed.3.The power main circuit topology of a hybrid bridge LLC resonant converter is deduced.The fundamental approximation analysis method is used to model the equivalentcircuit with resonant cavity as the core,and then the voltage gain is deduced.The mode of operation of the hybrid bridge LLC resonant converter in the whole cycle is analyzed.The model with total power of 4125 W is built by circuit simulation,and the simulation results are analyzed.A 150 W prototype is designed by reckoning.