| Radio power transmission technology(WPT)is also known as wireless power transmission technology.Compared with traditional wired power transmission,it has the advantages of safety,flexibility and convenience.This paper includes the selection of topological structure;the influence of system parameters on transmission performance;structure selection and parameter design of coupling coil;the control strategy of maintaining constant voltage output and constant current output is studied according to the load variation of the system.A charging mode of constant current and then constant voltage is designed by switching,and a simulation model is built to verify it.The experimental circuit was designed according to the simulation model,and the experimental platform was built for experimental verification.Firstly,the working principle and overall structure of different transmission modes are introduced,and then several transmission modes are compared.By introducing the mutual inductance equivalent model,the four basic compensation topologies of the magnetically coupled resonant type are compared.The series compensation extension circuit is selected as the compensation topology of wireless charging system,and the influence of load,coil mutual inductance,coil quality factor and working frequency on transmission efficiency and output power is simulated and analyzed by Matlab software.Secondly,Maxwell was used to build the models of coupling coils with different structures and simulate the magnetic field distribution.The coupling coil models of different structures built by Maxwell were imported into Simplorer for field path cosimulation,and the transmission efficiency of coupling coils of different structures was obtained.The most suitable coupling coil was selected based on the practical application.Then the effect of changing the vertical distance and horizontal deviation of the coupling coil on the coupling coefficient is simulated.The radius and number of turns of the coupling coil are designed to optimize the coil.Finally,according to the load variation of the system,the control strategy of constant current and constant voltage is studied to maintain the output voltage and current from the load variation.By switching the switch,the system can realize the phase charging mode of constant current and then constant voltage in the charging process,and the model is built for simulation verification.Based on the Matlab model,the experimental circuit was designed,and the complexity of the back-end constant current constant voltage control circuit was greatly simplified by the high-precision integrated power chip,and the experimental verification was carried out.Figure [55] Table [8] Reference [81]... |
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