Research And Design Of Parity Time Symmetric Wireless Charging Power Source Based On Back-end Control

After recent years of research and development,wireless power transfer technology has become increasingly mature,but there are also many challenges.The traditional wireless power transfer technology has a high sensitivity to coil shift.When the relative position between the coils and the resistance of the charging load change,it is easy to cause the system charging efficiency to decrease and the charging power to be unstable.However,the actual wireless charging system needs to have strong anti-shift and stability.Therefore,this thesis proposes a back-end-controlled parity time symmetric wireless charging power supply based on the principle of parity time symmetry for the system to have strong degrees of freedom and charging stability.designed a 35 W constant power wireless charging device.The main research contents of this thesis are as follows:Firstly,the background and significance of wireless power transfer are explained,and the research on wireless charging technology at home and abroad is reviewed,leading to the application of the parity time symmetry principle in wireless power transfer.The circuit model of the magnetic coupling mechanism is constructed with different theories,and then the theory of parity time symmetry in the wireless power transfer system is described,followed by the definition of negative resistance and its construction method,and the four basic topologies of the system are analyzed with the coupling mode theory and circuit theory,respectively,so that the series-string circuit topology is selected as the basic circuit topologyThen,the circuit model analysis of the energy storage battery was carried out to simulate the change of load during the charging process,and the mathematical modeling of the parity time symmetry wireless power transfer system is carried out through different theories,and the system frequency characteristics,voltage gain characteristics,and system transmission characteristics under the change of load and coupling coefficient are analyzed to achieve the anti-shift and stability of the system,respectively,and the analysis shows that although the parity time symmetric system has strong anti-shift resistance,the change of the load does affect the stability of the system.Based on this,a back-end equivalent load impedance control strategy is proposed,which can not only realize the load change The constant power charging of the system during the charging process does not affect the parity time symmetry region of the system during the charging process.Then,ANSYS Maxwell was used to analyze and select different coils for anti-deflection simulation,and suitable materials were selected for coil winding by analyzing the coil AC impedance.Finally,MATLAB/Simulink is used to simulate and verify the system main circuit parameters and control scheme.Based on the theoretical analysis and simulation verification,an experimental platform with an output power of 35 W is built for the system based on hardware and software design.The experiments show that the proposed back-end control-based PT-WPT system can achieve stable output power and transmission efficiency when the coil position and load resistance value vary within a certain range.