利用磁场在谐振线圈的共振耦合, 磁耦合谐振式无线传能技术可以提供中等距离和功率的传输。当收发回路耦合系数较高且处于过耦合状态时, 系统发生频率分裂现象, 激励源频率成为制约传输功率的重要因素。由于收发线圈之间的距离具有随机性的特点, 负载接收功率和额定功率难以恰好匹配。为了提高能量的传输功率及其稳定性, 经过系统建模和理论分析发现, 可以采用罗耶振荡电路对最大传输功率频点进行实时跟踪, 基于反馈链路的功率控制也是实现功率匹配的有效手段。实验结果表明, 采用罗耶振荡器和前端升压电路顺利完成无线传能系统的频率跟踪和功率控制, 实现在12 cm距离内5 W功率的稳定传输, 从而验证了能量传输过程中优化控制的有效性。

Using the magnetic coupling of two resonant coils, the aim of medium distance and power transmission can be achieved wirelessly. However, existing researches have shown that a frequency splitting phenomenon will occur when the magnetically coupled resonators are in over-coupled region, thus the frequency of exciting source becomes an important constraint factor for power increasing in the transmission. Moreover, because of the random feature of the distance between the transmitter and receiver, it is difficult to ensure the coincidence of the received and rated power. In order to improve the transmission power and the stability of the energy, system modeling and analysis are performed. It is found that Royer oscillator circuit can be applied to track the frequency points of maximum transmission power in real time. In addition, the received and rated power can be matched by the means of power control based on feedback link. It is shown that the system can realize a stable power transmission of 5 W within the distance of 12 cm in the experiments by means of Royer oscillator and boost circuit, which accomplishes the frequency tracking and power adjustment of the Wireless Power Transmission(WPT), and verifies the effectiveness of the optimal control in the energy transfer process.