电动汽车无线充电系统关键变量对系统效率的影响

On the Influence of Key Variables on System Efficiency in Wireless Charging System for Electric Vehicles

文章应用等效电路理论,建立了磁耦合谐振式无线充电系统数学模型,分析了电动汽车无线充电系统中负载电阻、补偿电容和耦合系数对系统传输效率的影响,给出了提高系统效率的指导性结论。结合电动汽车电池充电特性,提出一种应用于电动汽车无线充电的变频控制策略。最后,搭建了小型化实验平台并进行了实验。实验结果表明:在8 cm间距,输入149 V直流电压的条件下,实现了电动汽车先恒流2.9 A后恒压149 V的无线充电,最大输出功率432 W,最高效率约90.1%,平均效率约89.5%。

With the analysis of the key variables,the research on the transmission efficiency in wireless charging system for the electric vehicle is carried out.Firstly,employing equivalent circuit theory,a mathematical model of the magnetic coupled resonant in wireless charging system is established.Influence of three key variable loads,compensation capacitance,and coupling coefficient on system efficiency are analyzed,and a guiding conclusion for improving the system efficiency is given.Secondly,by analyzing the charging characteristics of electric vehicles,a frequency conversion control strategy is proposed.Lastly,a miniaturized experimental platform has been set up.The experimental results indicate that in the case of 8 cm spacing and input voltage of 149 V,the load is adjusted to simulate wireless charging experiment for electric vehicle with the conversion from constant current 2.9 A to constant voltage 149 V,maximum output power of 432 W,the highest efficiency of about 90.1%,the average efficiency of about 89.5%are obtained.