Research On Wireless Charging Optimization Of Magnetically Coupled Resonant Electric Vehicles

With the rapid development of the global economy,leading to increasingly strong demand for fossil fuels,resulting in fuel shortages and increasingly severe air pollution problems.Compared with fuel vehicles,electric vehicles have the advantages of green and clean,low price,renewable,etc.,and it is an effective measure to solve the energy shortage and air pollution.At present,it is still difficult to promote electric vehicles,and long charging times and low efficiency have limited the development of electric vehicles.This article focuses on the slow charging speed and low efficiency of electric vehicle wireless charging systems,which has practical significance for promoting the development of electric vehicles.Firstly,the overall structure of the wireless charging system for electric vehicles is briefly introduced,and the working process of the wireless charging system is described.Then,the mutual charging coupled mode theory is used to model and analyze the wireless charging system,and the parameters affecting the tra NSmission efficiency are obtained.In order to improve the tra NSmission performance of the system,four classical resonance compe NSation topology methods are analyzed,and finally the string-string resonance compe NSation topology method is selected.Then a charge control strategy based on fuzzy PID control is designed,and the controller is designed and analyzed.Finally,Simulink simulation experiments were performed to verify the correctness of the controller.Secondly,the hardware circuit of the system is designed and analyzed,including the control circuit,high-frequency inverter circuit and rectifier circuit.Based on the analysis of the different working modes of the high-frequency inverter and the rectifier,the inverter chooses a suitable full-bridge inverter mode,and the rectifier chooses an uncontrollable single-phase rectification mode.Then,based on Matlab / Simulink simulation platform,the main circuit of the charging system is modeled and the charging process is simulated to verify the correctness of the theoretical analysis.In the third part,the magnetic coupling mechanism,which is the core part of the wireless charging system of electric vehicle,is studied deeply,and the simulation analysis of the offset between the coils.Modeling and analysis of the magnetic coupling mechanisms of rectangular coils and space spiral coils,which are more common at present,are carried out by the finite element analysis method to obtain the change trend of the magnetic field distribution of the mechanism,and determine its offset tolerance.Then a new magnetic coupling mechanism is designed based on it,and compared with several other coil structures,it is verified that it has better anti-offset ability in different directions.Finally,the experimental platform is built for power-on experiment to verify the validity of the theoretical research and simulation analysis of this paper and the practicability of the device.