Sthdy Of Related Technique Based On Magnetic Resonance Wireless Energy Transfer

The magnetic resonance wireless power transmission technology has the advantages of far transmission distance,high transmission efficiency,high transmission power and so on.It's application prospect is wide.However,there are still many problems in the actual magnetic-coupled resonant transmission system.For example,the conversion efficiency of the inverter is low,and the whole transmission efficiency caused by the design of coupling coil parameter is too low and the electromagnetic pollution caused by the high frequency electromagnetic field.Based on the above facts,this paper gives a reasonable design of the circuit topology,the parameters of the coils and the high-frequency inverter source,and proposes a double-layer shielding based on the ferromagnetic metal and the non-ferromagnetic metal,in order to improve the transmission efficiency as far as possible and reduce the electromagnetic pollution caused by the existence of high-frequency electromagnetic field.The contents of this thesis are as follows:Firstly,the corresponding circuit models of two-coil structures are set up for four kinds,such as series connection-series connection,series connection-parallel connection,parallel connection-series connection,and parallel connection-parallel connection.The expression of transmission power and transmission efficiency is deduced by circuit-current method.The simulation results of Matlab combined with PSIM reveals the changing trend of transmission power and transmission efficiency with load resistance and transmission distance.Finally the series connection-series connection is selected and the coils are modeled by the electromagnetic simulation software Maxwell,the corresponding parameters of the coils are optimized.On this basis,the relationship between the parameters such as coil turns and coil radius with the transmission efficiency of the system is analyzed.Secondly,this thesis studies the wireless power transmission structure based on CLASS-E inverter,which has the advantages of simple structure,high transmission efficiency,and can design system power according to actual demand,so it is widely used.In this paper,the analysis of principle and the design parameters of CLASS-E are described in detail,and the correctness of the method is verified by the software PSIM.Then,this thesis studies the electromagnetic shielding technology based on the magnetic coupling resonant wireless power transmission technology,based on the single-layer aluminum shield,the structure of double-layer shielding of ferrite and the non-ferromagnetic metal is put forward,which solves the disadvantage that the transmission efficiency decreases greatly due to the resonant point offset caused by single layer shielding.At the same time,the electromagnetic pollution problems such as excessive magnetic field intensity in the non-electric power transmission area are greatly reduced,and the model of single layer shielding structure,the model of double-layer shielding structure and the model of double-layer shielding structure with ferrite strips are established by the software Maxwell,and the rationality of the shielding structure is verified by the contrast analysis.In the end,the experimental platform was constructed to verify the wireless power transmission structure based on the CLASS-E.And on this basis,the optimized electromagnetic shielding structure is also built.The results are as follows: The CLASS-E Radio energy transmission system with 68.6% transmission efficiency is realized experimentally with the transmission distance is 100 mm.The transmission efficiency with the transmission distance is 100 mm is only 63.2% when the shielding structure is not added.The magnetic field strength of the non-working region is reduced and the magnetic field strength of the working area is enhanced.The problem of electromagnetic pollution is suppress.The experimental results coincide with the simulation.It proves the rationality of the design of the electromagnetic shielding structure.