Research On Impedance Matching Optimization Design Of Wireless Power Transmission System

Wireless power transmission technology is a new type of power transmission technology.Compared with the traditional wire transmission method,it is safe,economical and convenient,and has been applied in many occasions.In order to improve the transmission power of the wireless power transmission system,it is necessary to match a certain impedance at the load end to maximize the transmission efficiency.However,the output power of wireless power transmission system based on traditional topology and impedance matching network is low,which can not meet the requirement of high power transmission.To solve this problem,this paper proposes a better performance LCC-S topology combined with impedance matching network for wireless power transmission,establishes the circuit model,and studies its transmission characteristics on this basis.The main contents of this paper are as follows:Firstly,the SS topology,SP topology and LCC-S topology are simulated by MATLAB software,and the results show that: compared with the former two topologies,LCC-S topology has more frequency points,which is less affected by frequency fluctuation and has better performance;When the frequency reaches the optimal frequency,LCC-S topology is more efficient than SS and SP topology.Based on this,the traditional topology of the system is replaced by a new LCC-S topology.On the basis of this topology,the impedance matching design of the radio power transmission system is carried out.Secondly,the principle of impedance matching is studied,and the impedance matching of transmission line,signal source end and load end is analyzed.On this basis,the impedance matching method of adding LC impedance transformation network at load end is selected.Finally,combining LCC-S topology with LC impedance transformation network,the voltage and current of LCC-S with impedance matching structure and without impedance matching structure are compared by PSIM simulation.It is found that the voltage and current amplitude of load end with impedance matching structure is larger,which indicates that the network with impedance matching has higher external output power.At the same time,PSIM simulation is used to compare LCC-S with impedance matching structure and S-S with impedance matching structure.It is found that LCC-S with variable resistance structure has higher voltage and current and higher external output power than the former at specific frequencies of 55 k Hz,85 k Hz and 110 k Hz.Finally,PSIM simulation verifies that the constant voltage output characteristics of LCC-S structure and the output power and efficiency of LCC-S structure with impedance matching are affected by load resistance,coupling coefficient and frequency respectively.It is found that the system can output constant power and efficiency only when the load changes,and can output higher power and efficiency at a specific coupling coefficient and frequency.