Design And Research Of A Magnetic Resonance Coupled Wireless Charging System For Electric Vehicles

In recent years,as the environment worsens and the energy crisis aggravates,electric vehicles have been rapidly developed and popularized,and electric vehicle charging technology is a relatively important aspect in the research and development of electric vehicles related technologies.The traditional plug-in charging is the main charging mode of electric vehicles at present,but it is easy to leak electricity and is greatly affected by the weather,causing great inconvenience to charging electric vehicles.Wireless power transmission technology is a newly emerging non-contact energy transmission technology,which is different from the traditional plug-in wired charging method.It is no longer affected by the environment and brings great convenience to the electric vehicle charging.The use of wireless power transmission technology makes electric vehicle charging flexible,convenient and practical.Therefore,it is of great practical significance to study the wireless charging transmission technology of electric vehicles.Magnetic coupling resonant wireless power transmission technology is to use two coils which separated by a certain distance as the transmitting coil and receiving coil of the energy respectively.By designing the topology circuit,the two coils have the same resonant frequency.Under the action of the high frequency excitation source,the two coils resonate and transmit the energy from the transmitting side to the receiving side.This paper studies the magnetic resonance coupled wireless charging technology of electric vehicles,mainly from the following aspects:(1)The coupling theory and circuit theory are used to analyze the energy transmission principle of the resonant system and four different topological circuits are analyzed.It is confirmed that the compensating circuit of electric vehicle wireless power transmission system adopts the serial-parallel topologycircuit structure.(2)Designing method of electromagnetic coupling mechanism for wireless power transmission system.A detailed analysis of resonant coil selection and parameter characteristics,the establishment of a different structure of the resonant coil model and the use of simulation methods for in-depth analysis and research.Research resonant coil diameter,shape and wire and the relationship between the system transmission efficiency.(3)Design an experimental high-frequency excitation source for electric vehicle wireless power transmission system.The circuit design of rectifier,chopper and high frequency inverter of high frequency excitation source in wireless power transmission system is studied in detail.In the DC chopper circuit,a new type of Buck chopper circuit is designed to realize the soft switching in the chopping process and reduce the energy loss of the power switch tube.High-frequency inverter circuit using soft-switching technology to achieve and design a zero-voltage detection circuit,the voltage on both sides of the power switch to detect and improve the reliability of the inverter circuit.(4)Design a set of magnetic coupling resonance test device of electric vehicle.The reliability and practicability of the designed device are verified through experiment.The energy transmission efficiency can reach 90% when the transmission distance is 10 cm.