磁耦合谐振式无线电能传输电动汽车充电系统研究

摘要

为研究电动汽车无线充电系统，解决电动汽车有线充电时的不安全、不便利问题，采用磁耦合谐振式无线电能传输技术，从改进传输线圈结构出发，在传输线圈外侧增加导磁体，将磁通尽可能束缚在两传输线圈之间，减小向外界的泄漏，缩短磁通在空气中的磁路长度，从而有效增强无线电能传输系统的耦合程度，大大增加传输功率，提高低频条件下的传输距离和效率。设计了具有频率自动跟踪控制的12 kW／70 kHz高效磁耦合谐振式电动汽车无线充电系统，并进行实验研究，得到一系列传输线圈距离和负载阻抗、传输功率及传输效率之间关系的实验数据。特别地，实验结果表明在传输距离0．3 m、输入功率12．6 kW时，谐振频率为72．6 kHz，传输效率达到94．33％。%In order to study the wireless charging system for electric vehicles ( EV) and to solve the un-safety and inconvenience for EV wired charging system, magnetically-coupled resonant wireless power transfer(MCR-WPT) technique was used.Structure of transmission coils was improved through adding magnetizer outside each coil,which could constrain magnetic flux inside these two coils,reduce the leak-age magnetic flux,and thus shorten the length of the magnetic circuit in the air.Therefore,the coupling degree of the transmission system was improved.Effectively,the transmission power is greatly increased and the transmission distance and efficiency are increased as well under low frequency condition.Moreo-ver,a 12 kW/70 kHz high-efficiency MCR-WPT EV charging system with automatic frequency tracking control was designed.A series of experimental data were acquired on the relationship between transmission coil distance and the load impedance/transmission power/transmission efficiency.Especially,experimen-tal results show that the resonant frequency is 72.6 kHz and the transmission efficiency is 94.33%which are achieved with distance being 0.3 m and input power being 12.6 kW.