| The technology of magnetic resonance coupling wireless power transmission is widely used in the field of wireless charging of electric vehicle,mobile phone,and fuze,which is safer,more convenient and has a more promising prospect than the traditional wired transmission.At present,the research on wireless power transmission technology mainly focuses on the system without interference of external objects around the energy transmission channel.There are few research on the technology of magnetic resonance coupling wireless power transmission under the influence of metal environment.It is necessary to develop the transfer characteristics of the magnetic resonance coupling and its optimization,which could provide theoretical reference for applications in engineering.During the process of energy transmission,the metal object produces eddy current on the surface under the influence of alternating magnetic field,which could cause interference to own parameters of the system coil and transmission performance.Based on this problem,a resistance correction parameter is introduced to set up the equivalent parameter correction model of coil impedance under the influence of metal tube,and establish the eddy current loss model under the influence of metal plate.Taking overall consideration about the cross-coupling effect of non-adjacent coils,the dual-coil,single-relay and dual-relay model under the influence of metal environment are completed,and to deduce transmission power of the system as well as the efficiency expression.Taking advantage of Maxwell and Simplorer electromagnetic simulation software to establish a simulation model of single coil and double coil system under the influence of metal environment,and it reveals the influence rule of metal medium of aluminum,copper and steel with different size,shape and relative positiorn on coil parameters and system transmission performance.It is found that the existing models can't accurately describe the influence of non-ferromagnetic metal medium on the coil resistance parameters.It clarify the non-linear trend of the coil resistance parameters under the influence of non-ferromagnetic metal medium.The variation of the resistance parameters is related to the gap and has a tendency of change demarcation point.The gap of aluminum pipe,copper pipe and coil is about 15 mm,and the gap of aluminum plate,copper plate and coil is about 25 mm.The experiment has proved the accuracy of the reference calculation formula of the correction resistance parameter under the influence of the aluminum tube by the numerical simulation.This experiment has studied the influence rules of different sizes of aluminum and steel metal media on the transmission performance of the system.The transmission performance of the system under different sizes of metal media decreases in various levels.Compared with the non-ferromagnetic metal media,the influence of ferromagnetic metal media is stronger,and the system transmission performance parameter drops more.The conclusions from experiment and simulation are same.Adopting the combination of theoretical analysis and experiment has optimized the radius and number of turns of the receiving coil with different shapes.The experiment proves that the transmission efficiency in the air increases by about 20%.It has proposed a variety of magnetic material optimization programs,and the simulation and experiment of the optimization program is proved being effective.Under the influence of the metal environment,the comprehensive optimization scheme has been proved by experiments that it could improve the transmission efficiency by nearly 10%. |
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