Research On Two Phase Interleaved Parallel LLC Resonant Converter

With the rapid development of the global economy,carbon emissions also increase rapidly,emissions from fuel vehicle are the main cause of increasing carbon.In the case of absence of oil resources and environmental degradation promote to automobile industry low noise,less emissions,high energy development direction.Protecting the environment has always been our goal,the advent of electric vehicles is bound to accelerate the pace of environmental protection.If we want to promote the widespread use of electric vehicles in the world,the relevant charge infrastructure must be synchronized.In this paper,the post-stage LLC resonant converter of the charging module is analyzed and studied,the advantages of the two-phase interleaved parallel LLC resonant converter are compared with the single-phase LLC resonant converter,and the closed-loop system is designed to improve the stability and dynamic performance of the charging module.As the single-phase LLC resonant converter topology is simple,in wide range of input voltage and load changes,primary power switch can achieve zero voltage open,high efficiency,power density,so more and more is taken seriously in the charge pile module.But because the input filter circuit only has filter capacitor,the electric vehicle be charged in large current with large output current ripple,large output current ripple will reduce the battery life.Although it is possible to reduce the ripple by increasing the output capacitance,but it is not conducive to reduce the charge module volume;the ripple wave overage will reduce the life of the filter capacitor,the service life of the charging module device is limited by the output filter capacitor life two-phase interleaved parallel LLC resonant converter has many advantages like a single-phase LLC resonant converter,in addition to effectively reduce the output current ripple,thereby reduce the size of the filter capacitor and increase the service life of the module.Firstly,the operation of the two-phase interleaved parallel-connected LLC resonant converter is analyzed,the theory and simulation is analyzed of the topologies of the LLC resonant converter with parallel output of series input and parallel input,the advantages and disadvantages of the two topologies are summarized.The LLC resonant converter of the series input structure has a better current sharing effect than parallel input.Then the influence of excitation inductance,resonant inductance and resonant capacitor on the DC voltage gain characteristics of the LLC resonant converter is analyzed.Secondly,designing the selected input series output parallel LLC resonant converter closed-loop parameter,the selection basis of important parameters of two-phase resonant converter is given.A 15 kW two-phase interleaved parallel LLC resonant converter is given a detailed control-loop design process.A simulation model of two-phase interleaved parallel LLC resonant converter based on voltage loop control in Matlab / Simulink is built.The steady state and transient state simulation waveforms of the closed-loop system of two-phase interleaved parallel LLC resonant converter are obtained.Finally,simulation results verify the correctness of the selected program.The two-phase interleaved parallel LLC resonant converter based on voltage closed-loop control not only has excellent dynamic performance,but also can effectively reduce the output ripple.