Research On Vehicles Charger Based On Half-bridge PFC

In this thesis, the author cooperate with a New Technology Development Co.,Ltd. of Shenzhen to design the3kW on-board charger which is used to chargeon-board lithium battery for hybrid vehicles, aiming to solve problems of thelithium battery in energy supply. The capacity of the battery is40A/h,346V. Inorder to reduce energy consumption, on-board battery of plug-in hybrid vehiclescan be charged during the night.The thesis firstly put forward to an option of main circuit topology for thecharger according to the comparison of common topologies used by PFC andisolated DC-DC, and choose a first stage Boost PFC and the second stagehalf-bridge DC-DC topology as the main circuit topology, topological parametersand the module circuits are also designed based on the actual design requirementsand conditions. According to the calculation of the parameters, we establishedsmall-signal model and design dual closed-loop controller for Boost PFC andhalf-bridge DC-DC circuit. After the small-signal model equivalent to thecontrolled object model, we control the object by using current and voltage PI inorder to achieve a satisfying output, make a small overshoot, rapid response andgood stability. According to the design and the calculation of the topologicalparameters, we simulated and experimentally analyzed the two-stage half-bridgePFC circuit (Boost PFC circuit, half-bridge DC-DC) for vehicle charger powersupply in Matlab, which is resulted in satisfaction that the input current is able totrack the input voltage waveform well, and the output current and voltage cancharge the battery with constant current and voltage stably. Charging circuit is builton experimental platform to do charging experiment for batteries and to analyzeexperimental results.As the efficiency of two-stage half-bridge PFC circuit is somehow low, inorder to improve the charging efficiency and to reduce consumption, we analyzedand explored the use of single-stage half-bridge PFC circuit on the vehicles chargerpower supply. Due to that PFC circuit and half-bridge circuit share a IGBT, it canreduce the switching devices and losses, which will improve the efficiency, thus weare able to achieve not only power factor correction function but also energytransfer functions. Simulation analysis of single-stage half-bridge PFC circuit verifythat it works, and current closed-loop control system based on single-stagehalf-bridge PFC circuit for vehicle charging power supply could achieve bettercontrol effect.