磁耦合谐振式WPT系统频率特性分析

Analysis of Frequency Characteristics in Magnetically-coupled Resonant Wireless Power Transfer System

磁耦合谐振式无线能量传输技术能够实现中远距离的高效能量传输,给人们的生活带来极大的便利,更加符合未来社会发展的方向。该技术中频率的变化会对系统的传输性能产生重要的影响,频率特性的分析对提高系统的传输性能具有重要意义。为此,通过利用互感理论,分析了在理想和非理想状态下距离、负载的变化对系统输出功率最佳工作频率和传输效率最佳工作频率的影响。结果表明:理想状态下在研究系统最大效率工作频率时不能忽略频率对线圈内阻的影响;非理想状态下系统的传输效率最佳工作频率为接收端的共振频率,与距离、负载的变化无关。在MATLAB环境下仿真证明了上述理论分析的正确性。

A large amount of convenience can be brought by magnetically-coupled resonant wireless power transfer(MCR-WPT)which has the advantage like efficient energy transfer over medium and long distances and more in line with the direction of future social development.In this technology,the change of frequency will have an important impact on the transmission performance of the system.The analysis of the frequency characteristics is of great significance to improve the transmission performance of the system.To this end,by using mutual inductance theory,the influence of distance and load variation in ideal and non-ideal states on the optimal operating frequency of system output power and transmission efficiency is analyzed.The result shows that it’s inadvisable to neglect the frequency influence on coil’s resistance when seeking for the optimal operating frequency of transmission efficiency in desirable situation.Meanwile,in the non-ideal state,the optimal operating frequency of transmission efficiency is the resonant frequency of receive circuit,which immune from the variations of loads and distance.The accuracy of theoretical analysis is demonstrated in MATLAB.