Research On Metamaterials Design And Its Enhanced One-and Two-Phase Magnetically Coupled Resonant Wireless Power Transfer System Transmission Characteristics

Among different kinds of wireless power transfer(WPT)technologies,magnetically coupled resonant(MCR)WPT has been considered as one of the most promising technologies over recent years for the superiority of long transmission distance,high efficiency and transmission power,and immunity from non-magnetic obstacles in the mid-range WPT applications.However,there are still two significant drawbacks in its applications: spatial scales of coils including transmission distance,lateral misalignment and angular misalignment may vary randomly,causing fluctuations in output power and transmission efficiency;power transmission efficiency is not high enough and distance is still limited.In this thesis,a MCR WTP system working in medium-frequency 9MHz is designed and a solution is provided according to the problems mentioned above by changing the structure of the transmitting coil of the MCR WPT system and introducing negative-permeability metamaterials.The main research contents of this thesis are as follows:(1)The mathematical models of the one/two-phase MCR WPT system were established.The distribution of spatial magnetic field around the transmitting coil was studied and the influence of spatial position change of one/two-phase MCR WPT system on transmission efficiency was also analyzed from the perspective of magnetic field.(2)Adding negative-permeability metamaterials between the resonant coils was proposed to enhance the transmission characteristics of MCR WPT system.And a spiral negative-permeability metamaterials plate was designed and fabricated.The MATLAB program of scattering parameter was written.Combining with the scattering parameters derived by HFSS,then the equivalent permeability curve of the metamaterials was calculated through numerical simulation.And the influence of different parameters of the spiral metamaterials structure on the resonant frequency was analyzed and compared.(3)A Class E power amplifier working as the driving source of the MCR WPT system was designed.The circuit was simulated by using ADS and the PCB circuit of the power amplifier was drawn by Altium Designer.And then the entire PCB board was assembled after selecting the appropriate components.(4)A class E power amplifier test experimental platform and a one/two-phase MCR WPT system test experimental platform were set up.The former is designed to test the working condition of the class E power amplifier,the latter is to verify the feasibility of enhancing one/two-phase MCR WPT system transmission characteristics with the negative-permeability metamaterials.This thesis proposes a one/two-phase MCR WPT system based on negative-permeability metamaterials,which aims to solve the problems caused by the position change of the receiving coil of the WPT device and enhance the system characteristics.And the achievement of this thesis has important theoretical and practical value.