一种优化工作频率范围的无线充电系统研究

Research on a Wireless Charging System to Optimize the Operating Frequency Range

无线电能传输(WPT)是一种方便灵活的电能传输方式。目前对车载电池的充电多采用先恒流(CC)再恒压(CV)的充电方式。在WPT系统中,逆变器的零电压开关(ZVS)技术能进一步提高系统效率。此处以串联-串联(SS)型谐振式无线充电系统为研究对象,运用电路理论建立其等效电路模型,推导出系统电压增益和跨导增益关系表达式。采用变频移相控制策略分析无线充电系统分别工作在CV和CC模式时,逆变器工作在ZVS状态下的频率范围。通过理论分析发现,设置一定的移相角可以使系统的工作频率范围缩小,使无线充电系统工作在优化的频率范围中。最后,搭建了仿真模型和实验平台对其进行了验证。

Wireless power transfer(WPT) is a convenient and flexible method for electrical energy transfer.At present,the charging method of constant current(CC) and then constant voltage(CV) is mostly used to charge the car battery.In the WPT system,the zero-voltage switching(ZVS) technology of the inverter can further improve the system efficiency.The series-series(SS) resonant wireless charging system is taken as the research object, circuit theory is used to establish its equivalent circuit model,and the relationship expression of the system voltage gain and trans-conductance gain is derived.The frequency conversion phase shift control strategy is used to analyze the frequency range of the inverter working in the ZVS state when the wireless charging system works in CV and CC modes.The theoretical analysis shows that the operating frequency range of the system can be reduced by setting a certain phase shift angle,which can make the wireless charging system work in an optimized frequency range.Finally,a simulation model and an experimental platform are built to verify our proposal.