Resonant Wireless Power Transmission Distance Characteristics And Improvement Methods

As a technology with great potential,wireless power transfer has received great attention from researchers around the world in recent years.This technology can free the transfer of power from the restrictions of wires and has broad application prospects,then it could be used in smart homes,medical,wearable devices and rail transit.In the future,the universal application of wireless power transfer technology will greatly promote the progress of human society.The wireless power transfer via coupled magnetic resonances technology has good power transfer performance and it can achieve efficient power transfer over long distances.In addition,the requirement of directionality is not high,so this technology has important research significance.In the development of wireless power transfer via coupled magnetic resonances technology,the problem that transfer power and transfer efficiency decrease sharply with the increase of transfer distance needs the most attention.To solve this problem better,the system equivalent model and finite element simulation are used to study the distance characteristics of the wireless power transfer via coupled magnetic resonances system in detail.And according to actual situation,the research on the influencing factors to increase the transfer distance are conducted.After analyzing theory and simulation,an experimental device of wireless power transfer via coupled magnetic resonances system is built.Firstly,the transfer principle of the WPT is analyzed in this dissertation,and the frequency response of the load receiving power is obtained after building the system equivalent model,and the resulting graph shows the trends of transfer power,system efficiency,coil efficiency and matching efficiency,and the factors increasing transfer distance are analyzed.Secondly,based on the theoretical analysis of the system distance characteristics,the finite element software is used to simulate the actual working environment of wireless power transfer via coupled magnetic resonances system,and the influence of coil shape,radius,turns,spacing and wire conductivity on transfer distance are obtained.The effects of three basic winding methods,increasing the system resonant frequency,and adding a magnetic core on the improvement of the transfer distance of system are compared.The presence of obstacles on the transfer path is analyzed,the trends of transfer performance and corresponding solutions are given.Finally,an experimental device is built based on the simulation model.In the case of changing the coil parameters,increasing the system frequency and the presence of obstacles,the distance characteristics are measured.Then,the experimental data of transfer power,transfer efficiency and transfer distance are obtained.And there are good consistency after comparing with the theoretical calculations and simulation results,which proves the correctness of the conclusions and the validity of the method.