| In recent years,the dynamic research of magnetic coupling resonant radio power transmission for electric vehicles has been concerned by scholars at home and abroad.Improving the transmission efficiency and output power of electric vehicles has always been the research goal of dynamic wireless charging technology,and the improvement methods,such as topology optimization,coupling coil parameter optimization and so on.However,due to the lack of physical connection and the offset between the transmitter and the receiver,the dynamic wireless charging system for EV is not efficient.Based on the resonance compensation structure and coupling structure,these focuses on the method of improving the transmission efficiency and anti-offset characteristic of EV dynamic wireless charging system.Firstly,the mathematical models of LCCL-S compensation,LCCL-LCCL compensation and LCL-S compensation are established based on the analysis of four classical topologies.After analyzing their frequency characteristics,ZVS softswitching characteristics,voltage and current characteristics and transmission performance characteristics,the LCCL-LCCL resonant compensation structure is selected to study the dynamic characteristics of MCR.By analyzing the characteristics of LCCL-LCCL resonant compensation topology,it is proved that the transmitter can keep stable magnetism,and the equivalent impedance of the receiver can satisfy pure resistivity,which is helpful to enhance the transmission efficiency of traditional dynamic wireless charging system.Secondly,aiming at the problem that the current dynamic wireless charging system of electric vehicle has poor anti-deflection characteristic,a kind of cross circular coupling structure is designed,and the characteristics of a single circular coil are studied by using the finite element analysis software,mainly including:(1)the design and selection of the coupling coil;(2)the analysis of the self-inductance,mutual inductance and anti-deflection characteristics of the coupling coil;(3)the analysis of the radius,diameter and turns of the coupling coil;and(4)the analysis of the magnetic shielding characteristics of the coupling coil.Through the simulation analysis of Ansys Maxwell,it is found that the circular coil coupling mechanism has the advantages of uniform magnetic induction,high coupling degree and strong anti-deflection ability.Finally,the coupling mechanism of the system is circular cross coil,and a set of working frequency of 85 KHz,axial transmission distance of 200 mm and excitation of42 A is built by using Maxwell and Simplorer software.In order to improve the transmission efficiency and output power stability of the system,the optimal phase difference between adjacent transmitting coils is found. |
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