Research On Wireless Charging Technology Of Electric Vehicle Based On Magnetic Coupling Resonance

The main reason for the current development of electric vehicles is the inconvenience of charging electric vehicles.Compared with traditional wired charging technology,wireless charging technology has the advantages of simplicity,flexibility and security.Compared with the other three wireless charging technologies,the magnetically coupled resonant wireless charging technology has been widely studied because of its long conduction distance,high conduction efficiency,and strong anti-offset capability.Firstly,the thesis introduces the composition and working principle of the wireless charging system of the magnetic coupling resonant electric vehicle.The mutual inductance coupling model is used to analyze the mechanism of the resonant power transmission technology.The LCC-S composite resonance compensation structure is selected as the resonance structure studied in this thesis,and the circuit theory analysis is carried out.Secondly,in the design of the coil,the simulation models of several common coils in the ANSYS simulation software are analyzed under the equivalent conditions from the spatial distribution of the magnetic field,the degree of coupling mutual inductance between the coils and the actual situation of the vehicle-mounted device.Select a single layer flat circular coil.In the core design,the common manganese-zinc ferrite is discarded,and the iron-based nanocrystalline alloy is used as the core material of the coil.The iron-based nanocrystalline alloy has higher magnetic permeability than the manganese-zinc ferrite and can be improved.The coupling of the coil and the reduction of the magnetic loss of the core reduce the temperature rise of the electromagnetic coupler.The magnetic circuit equivalent model is used to analyze the magnetic field of the electromagnetic coup ler,and the optimized direction is added to increase the magnetic core at the edge of the magnetic field to increase the coupling degree of the entire electromagnetic coupler and design a structure with strong anti-offset capability.At the same time,in view of the uneven magnetic field density in the electromagnetic coupler,the magnetic strip density inside the electromagnetic coupler tends to be uniform by replacing the thick and uniform magnetic strip with a non-uniform magnetic strip,which reduces the volume and magnetic loss of the core.Keep the degree of coupling and offset ability unchanged.At the same time,the electromagnetic safety problem of the wireless charging system has been paid attention to.The wireless charging system charging simulation model is built in ANSYS,and the iron plate is used to replace the automobile chassis to study the magnetic field distribution around the charging device.The method of surrounding the launching disk by the horizontal aluminum plate is used to solve the problem that the horizontal magnetic field strength of the transmitting disk exceeds the standard,and the magnetic core is added at the bottom of the transmitting disk to maintain the original self-inductance and mutual inductance.Then design the hardware circuit according to the requirements of the wireless charging device,and build the simulation circuit of the charging system in MALTB/SIMULINK.To verify the correctness and effectiveness of the above design.