考虑非纯阻性负载阻抗匹配的无线充电系统

A wireless charging system considering impedance matching of non-pure resistive loads

为了提高电能传输效率,提出一种基于动态电容和Boost-Buck变换器的无线充电非纯阻性负载阻抗匹配的方法。可根据负载变化来改变电容和Boost-Buck变换器开关管占空比,分别补偿负载的虚部与实部,从而达到最佳阻抗点以提高系统传输效率。在MATLAB/Simulink环境下搭建系统仿真模型,并建立系统实验平台。仿真与实验结果表明,当接不同性质负载时,所提出阻抗匹配方法的系统传输效率都比未进行阻抗匹配时的高,最大系统传输效率可达83.14%,比无阻抗匹配提升了3.21%。同时,在等效阻抗为18~35Ω时,系统传输效率均保持在80%以上,具有阻抗匹配范围大的性能。

To increase the power transmission efficiency of wireless charging system,anon-pure resistive load impedance matching method based on a dynamic capacitor and a Boost Buck converter was presented.The capacitance and the duty ratio of the Boost Buck converter was controlled to follow the resistance variation when the batteries were charging by the presented method.By compensating the imaginary and real part of the impedance load,the optimal impedance point was achieved and the power transmission efficiency of the wireless charging system was improved.To verify the effectiveness of the presented method,a simulation model in the MATLAB/Simulink environment and an experimental platform were built.The simulation and experimental results show that the system transmission efficiency using the proposed method is improved under different loads conditions compared to no impedance matching.The maximum transmission efficiency of the system using the presented method can reach 83.14%,which is 3.21%higher than the system with no impedance matching.Moreover,the system transmission efficiency can achieve above 80%when the equivalent impedance changes from 18Ωto 35Ω.It indicates that the impedances variation of a wireless charging system can be well followed and matched using the proposed method even in a wide range of impedance variation.