Design Of Full Bridge LLC Resonant Converter For Vehicle Charging Piles

New energy vehicle is a vehicle that uses electricity as energy and motor as power source.Compared with traditional cars,there are many advantages.First,it helps to change the structure of energy consumption.Oil resources have been heavily dependent on imports for a long time,which is very unfavorable to China's future energy development and economic development.Secondly,it helps to improve the ernvironmental problems.Haze is one of the most serious environmental problems in China.The exhaust emissions from traditional cars are the main source of haze.Therefore,vigorously developing new energy vehicles,reducing the use of fuel vehicles and reducing vehicle exhaust emissions can effectively improve the haze problem.Finally,it will help China become a powerful country in automobile production and sales.The new energy automotive industry has just started,and the starting points of all countries are similar,which means that China has the opportunity to change the situation that the automotive industry has lagged behind other automotive powers for a long time.It can even take advantage of this industry change to surpass them and become the global leader of new energy vehicles.At present,China's new energy automobile industry chain has become increasingly mature,China has advantages in battery management and motor control technology.Depending on China's increasingly powerful R&D capability of new energy vehicles,we can vigorously promote the development of new energy vehicles,bypass the two long-term catch-up roads of engines and gearboxes,and lead the rest of the world on the road to the development of the automotive industry.With the vigorous development of new energy vehicles,charging piles have become an indispensable condition for the development and popularization of new energy vehicles.Therefore,the new energy vehicle charging equipment has a broad market demand.It is of great significance to develop a high-performance charging equipment to meet the market demand to meet the urgent needs of the market and meet the needs of social and economic development.The front stage of charging pile is a three-phase three-level rectifier based on VIENNA topology.Its function is to convert three-phase AC from power grid into DC which meets the requirements of power factor and total harmonic distortion rate.The latter stage is a DC converter based on full bridge LLC resonant topology,which converts the rated voltage DC from PFC to DC with wide regulation range.This paper mainly introduces the research and design of full-bridge LLC resonant converter,and introduces in detail the following aspects:(1)Comparing the current mainstream topology schemes,combining with the requirements of this topic,it is found that the full-bridge LLC resonant topology has unique advantages in DC-DC converter design.It is the best choice of main circuit topology.(2)The theoretical analysis of full-bridge LLC resonant topology,based on which the design process of resonant cavity parameters and main transformer are introduced in detail.Then the control circuit and other related circuits are designed to complete the hardware design of the whole converter system.(3)An open-loop simulation system is built in Simulink module of Matlab to verify the rationality of the main circuit design of full-bridge LLC resonant converter.Secondly,the control strategy is studied and designed.The double closed-loop PI controller of PFM driving signal is used for the design of the converter system,and the simulation is carried out.(4)After completing the hardware design and control strategy research of the converter system,the software design based on the control chip of TMS320F28335 is introduced in detail.