Design And Implementation Of Wireless Charging System For Electric Vehicle

With the shortage of non-renewable resources and the aggravation of environmental pollution,electric vehicles have developed rapidly.Compared with the cable contact charging,wireless charging technology can make charging operation faster,and there is no common contact wear of plug and socket.It can reduce the risk of electric shock in bad weather and has a good market prospect.Wireless charging system applied to electric vehicles is studied in this paper.The main research contents are as follows: 1.The research background of wireless charging technology is briefly introduced.Classification and development of wireless charging system are summarized.2.The basic principle of wireless charging system is introduced.The realization method of wireless charging is analyzed.The existing international wireless charging standards are summarized.Several different equivalent circuit models of electromagnetic coupling device are introduced.The equivalence of transformer model,mutual inductance model and T-model is verified.The principle,advantages and disadvantages of four basic compensation networks are analyzed,and the maximum efficiency and maximum power point of different compensation networks are solved.3.The electromagnetic coupling devices in wireless charging system that have a great impact on efficiency are studied in detail,and several common electromagnetic coupling devices are summarized.Aiming at improving the coupling coefficient and transmission efficiency,the circular electromagnetic coupling device is optimized and analyzed based on the finite element simulation software ANSYS Maxwell.The influences of outer diameter,number of turns,interturn distance,ferrite and shielding plate on the coil coupling coefficient are explored.In order to improve the anti-misalignment performance of the electromagnetic coupling device,a new structure of electromagnetic coupling device is proposed,which can maintain high coupling coefficient when the misalignment is half of the outside diameter.4.Converter need to deal with input and output of the electromagnetic coupling device.Hardware and software design of wireless charging system including the main circuit topology and control strategy are carried out.Simulation is implemented in MATLAB.Silicon carbide device is used in order to improve performance under the circumstance of high power and high frequency.It can lower switching and conduction losses and improve the overall efficiency.The heat dissipation scheme of high power device is designed.5.The experimental research on wireless charging system is carried out.The experimental platform of the wireless charging system is set up.The 8kW high-power experiment is carried out by connecting high-frequency transformers between converters,which verifies the reliability of the converter design scheme.The electromagnetic coupling device is processed and manufactured,and the wireless charging experiment of 3kW is conducted with the circular electromagnetic coupling device.The efficiency reached 93.5% when the distance is 150 mm,which verified the performance of the proposed design scheme.The misalignment experiment of the new electromagnetic coupling device proves that the new electromagnetic coupling device has better anti-misalignment characteristics than the circular coupling device.Effectiveness of the system is verified by experiments.