偏谐振工作状态下的无线电能传输系统

Wireless power transfer system based on the mode deviating from the resonance

串串型谐振式无线电能传输系统(Wireless Power Transfer,WPT)工作在谐振状态下时,为了避免系统失谐,需要复杂的频率跟踪控制,而且当耦合互感M=0时,系统发射端串联谐振,发射线圈寄生电阻上会有较大的功率消耗,导致安全隐患。针对上述问题,设计WPT系统处于偏离谐振点工作模式,使激励源频率大于发射端和接收端的谐振频率,利用次级回路的反射容抗抵消初级回路的感抗,无需频率跟踪而且可以实现M=0时低功率输出。基于半桥逆变和E类功率放大器设计两套小功率WPT样机验证上述工作状态的有效性和普适性,实验结果表明偏谐振模式下M=0时WPT样机消耗功率小于2 W,M≠0时系统输出功率和效率随着M的增加而提高,可实现19. 1 W的功率输出和86. 3%的传输效率。

In the working process of series-series wireless power transfer(WPT)system,in order to avoid the occurrence of detuning,complex frequency control is needed.When the coupled mutual inductance M≠O,the transmitter resonates and large power will be consumed on the parasitic resistor of primary coils,which will lead to the security risks.Regarding the issues above,a worl^ing mode that tlie operating frequency of tlie WPT system is larger than the resonant frequency of transmitter and receiver,was proposed.In this mode,the capacitance reflected from the secondar circuit could be used to counteract the inductance of the primary circuit.There is no need for the frequency tracking and the system having low output power when M≠O.In order to verify the validity and universality of the working mode,two WPT prototypes were designed respectively based on the class Eamplifier and half-bridge inverter.The experimental results show that in the proposed mode,the output power of botli WPT prototypes is less than 2 W when M≠O.Meantime,with the increase of M,both the output power and efficiency rise and the prototype reaches the transfer efficiency of 86.3%at 19.1 W output power.