Research On Transmission Characteristics Of Magnetic Coupling Resonant Wireless Charging For Electric Vehicles

With the gradual popularity of electric vehicles,the charging technology of electric vehicles also continues to put forward higher requirements.At present,charging piles are commonly used in the market to charge electric vehicles,and there are problems such as interface mismatch and leakage in humid environment.Therefore,in order to further meet the charging requirements and maximize the charging power,this paper investigates the transmission characteristics of magnetically coupled resonant wireless charging for electric vehicles.Firstly,this paper analyzes and summarizes the types of wireless charging technology and the status of domestic and international research,and selects the series-string type as the resonant structure in this paper by analyzing four basic resonant structures.The power and efficiency models of wireless charging system are established based on circuit theory,and the established models are verified by using coupled mode theory,which demonstrates that the efficiency model has equivalence and provides a theoretical basis for the subsequent research.On this basis,the system characteristics are analyzed,and the output power of the system can reach the maximum value whenk k(?)=1.Secondly,three commonly used coil structure types are compared and analyzed,and a theoretical model of circular laminated coil is established to study the influence of coil structure parameters on the system.Simulation verification is also performed using Ansys Maxwell software to demonstrate the rationality of the theoretical model.For the main parameters affecting the performance of the theoretical model,a set of optimal parameter solutions are obtained using an improved particle swarm algorithm.Finally,an improved coil structure model is built using Ansys Maxwell software to study the effects of axial distance,radial distance,and deflection angle between coils on the system when the electric vehicle is being charged.With the cores loaded on both sides of the coil,the effects of the core radius and thickness variations on the inter-coil coupling coefficient are analyzed.When the intercoil coupling coefficient reaches the maximum,the mathematical relationship between the core radius and thickness is constructed.The deflection characteristics of the coil without core,with cores on both sides of the coil,and with cores and shielding devices loaded on both sides of the coil were compared and analyzed,and it was found that the effective axial distance increased from 400 mm to 440 mm,the effective radial distance increased from 215 mm to 245 mm,and the effective deflection angle increased from 54 degrees to 57 degrees.