磁场耦合无线电能传输系统最大功率要素分析

Approach for maximum power transfer of magnetically coupled wireless power transmission system

针对无线电能传输系统的功率和效率问题,在特定频率下研究了影响无线电能传输系统最大传输功率的若干要素。以磁场耦合单元为核心建立简化模型,包括发射回路、接收回路,以及两个回路之间的磁场耦合单元。分别研究发射回路电抗、接收回路电抗、互感电抗等在单独变化,或协同变化时,如何影响最大功率传输条件,最大功率值和传输效率等。研究发现,不同情况下的最大功率传输条件之间存在内在联系;在发射回路与接收回路电阻乘积较小时,松耦合谐振才能传输最大功率。此结论不依赖于阻抗补偿形式,并且对感应耦合式和磁场共振式无线电能传输系统均适用。仿真和实验结果与理论分析结果一致。

In order to improve the power and efficiency of wireless power transmission （WPT） system, the essential factors that affect the maximum power of WPT system on the special frequency were investiga- ted. Firstly, taking magnetically coupled unit as the core of WIT system, simplified model was presented, which includes the transmitting circuit, the receiving circuit, and the magnetically coupled unit between them. Then, the parameters, such as the reactance of transmitting and receiving loop, the reactance of mu- tual inductor,were taken into account to study the conditions for transmitting maximum power, the maxi- mum power and the transmission efficiency, when the parameters varied individually and dependently. The results show that there are internal relations between the conditions for transmitting maximum power; only the loose coupling resonance can reach the maximum power transmission, if the product of the resistance of transmitting and receiving loop is smaller. The conclusions are not related to the impedance compensa- tion network, and can be applied to both inductive coupling and magnetic resonance WPT system. Simula- tions and experimental results confirm the conclusions.