Research On Magnetically Coupled Resonant Wireless Energy Transmission Coil And Transmission Direction Change Characteristic

With the rapid development of society,people’s demand for electric vehicles,consumer electronics products and implantable medical devices is increasing.The power supply of these devices is also increasingly becoming a prominent issue.Compared to wired cable power supply,wireless power transfer(WPT)has gained more and more attention due to its greater flexibility,higher security and longer service life.Based on the theory of magnetic coupling resonance,this paper studies the structure,performance parameters,transmission direction,transmission efficiency and other characteristics of the dual-frequency wireless power transmission coil.The specific research content is as follows:1.One kind of dual-frequency wireless power transmit-receive coils is optimized,and two kinds of dual-frequency wireless power transverse coils are designed based on the theory of magnetic coupling resonance.The transmission efficiency of the transmit-receive coils under the ideal condition of positive alignment in three coils WPT systems is analyzed,simulated and measured.The transmission efficiency of the three different coils WPT systems in the low frequency bands and the high frequency bands is obtained,and the experimental results are in good agreement with the simulation ones.2.The coupling coefficient and scattering coefficient of the three coils are simulated by using professional electromagnetic simulation software when the two coils shift in the X direction,Y direction and X=Y direction.The anti-offset ability of the three structures in three different directions of X,Y and X=Y was obtained.The excellent anti-offset ability is verified for coils with the evenly distributed magnetic field in WPT system.3.The following conclusions are drawn after the theoretical analysis,model simulation and experimentation for three kinds of coils with different angular deviation.There is a critical deflection angle of about 30° for two coils WPT system with angular deviation verified by theoretical analysis,simulation and actual measurement for all of the three coils with different structures.The transmission efficiency decreases slower when the deflection angle of the two coils is less than the critical angle,while it’s faster when the deviation angle of the two coils is larger than the critical angle.The critical angle is about 30° for two coils WPT system in the three kinds of coil structures.The transmission efficiency of every two coils deviation for 30°,60° and 90° is simulated by professional electromagnetic software and measured through constructing experimental platform.The comparative experiments which are with or without a relay coil added for every 30° deflection angle are conducted,and it can significantly improve the transmission efficiency of the WPT system by adding relay coils when there is a large angular deviation between the transmitting coil and the receiving coil.