Research On The Evaluation Method Of The Interoperability Between The Coupled Coils Of The Electric Vehicle Wireless Charging System

The interoperability of electric vehicle wireless charging systems refers to the ability of any power supply device and electric vehicle to perform safe,efficient,and stable wireless energy transmission through magnetic field coupling based on relevant specifications.The research object of this subject is the wireless charging system of electric vehicles,which mainly analyzes and studies the interoperability between circuit compensation topology and coupling coils with different structures.First of all,the mutual inductance model theory is used to build an electric vehicle wireless charging system model,specific expressions for different circuits to compensate for the transmission power and efficiency of the topology are derived,and the system's transmission performance from the perspective of interoperability are analyzed to obtain the impact.Based on the key parameters derived in this dissertation,an interoperability impedance interface is defined.This interface can be used to switch the coupling coils of different structures,and a method for evaluating the interoperability of coupling coils with different structures in the same circuit compensation topology is proposed method.This method needs to set the reference ground and vehicle-end equipment and the reference impedance area based on the interoperability impedance interface in advance,and then compare the impedance area obtained from the coupling coils of different structures with the reference area to analyze the range of impedances falling within the reference area The larger the range that falls within the reference impedance region,the better the interoperability between the two coils.Secondly,in order to verify the correctness of the proposed method,the square,circle,and DD-type coils are used as transmitting coils,respectively,and uses the method of finite element analysis to study the interoperability between each other from the system transmission efficiency and power fluctuation.Multiple angles such as range and coupling coefficient were compared.The transmission power of the points where different combination coils fall in the reference impedance region and the offset positions corresponding to the points outside the reference impedance region are calculate,and a conclusion that supports the work of this dissertation is drawed.Based on the Z_VA and Z_GA derived from the two-port interoperability impedance interface of the circuit,it proves that the system transmission efficiency of the points falling within the reference impedance area meets the efficiency defined in this dissertation is 85%when the efficiency is positive and 80%when there is an offset.It is required that the points outside the reference impedance region generated by the coil coupling cannot achieve the above requirements,which proves the correctness of the work of this dissertation and the correctness of the proposed method.Finally,through the interoperability experiment platform of the electric vehicle wireless charging system,the method proposed in this dissertation for evaluating the interoperability between coils with different structures is experimentally verified,and the reference device and reference impedance are defined by the same method as the simulation analysis.Compared with the impedance region generated by the coupling of different combination coils and the reference impedance region,the experimental conclusions are in good agreement with the simulation analysis conclusions.The method proposed in this dissertation for evaluating interoperability has certain guiding significance.