Optimization Design Of Electromagnetic Shielding For Wireless Power Transfer System

Wireless power transfer（WPT）is a technology that uses the electromagnetic field or electromagnetic wave distributed in the space to transfer the power from the transmitting end to the load side through non wire connection.Compared with the traditional power transmission,WPT has higher security and convenience.With the progress of national science and technology,people have made in-depth research and improvement on wireless power transfer technology,and its application field has expanded year by year.It is of practical significance to use electromagnetic induction or magnetic resonance wireless power transfer technology to provide electric energy for electric vehicles,which improves the flexibility of charging process,And it may become an important way of electric vehicle charging in the future.When the magnetic coupling resonant wireless power transfer technology is used to charge the electric vehicle,due to the outward diffusion of the magnetic leakage field in the working process of the technology,when one transmitting coil transmits power to two receiving coils which are close to each other,the coupling caused by the magnetic leakage field between the receiving coils will interfere with the resonance parameters of the system and reduce the working efficiency of the system.In view of this situation,a shielding coil is designed between two receiving coils to eliminate the coupling between the coils,improve the working environment of the system and enhance the efficiency of the wireless power transfer system.The control variable method is used to optimize the wireless power transfer system by studying the shielding coil,resonant capacitance,axial distance,load resistance,the change of shielding coil turns,radius,different materials,etc.The results show that the transmission efficiency of shielded coil is higher than that of unshielded coil,and the improvement is obvious.When the resonant capacitor resonates,the transmission power and efficiency of the system are the highest.The larger the axial distance is,the lower the transmission power efficiency is.When the load resistance is the same,the transmission power efficiency is the highest.The larger the number of turns of shielding coil,the higher the transmission power efficiency of the system.The larger the shielding coil radius is,the more obvious the transmission power efficiency is.The larger the permeability of the shielding coil material is,the better the shielding effect is,and the higher the transmission power efficiency is.The effect of ferromagnetic material is better than that of non ferromagnetic material.