Basic study of improving efficiency of wireless power transfer via magnetic resonance coupling based on impedance matching
Basic study of improving efficiency of wireless power transfer via magnetic resonance coupling based on impedance matching
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DOI：
10.1109/isie.2010.5637484
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发表时间：
2010-07
期刊：
影响因子：
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通讯作者：
T. C. Beh;T. Imura;Masaki Kato;Yoichi Hori
中科院分区：
文献类型：
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作者：
T. C. Beh;T. Imura;Masaki Kato;Yoichi Hori
无线电力传输对于电动汽车（EV）的普及至关重要，因为它提供了一种安全便捷的电动汽车充电方式。最近，提出了一种使用电磁谐振耦合的高效中程无线功率传输技术WiTricity。研究表明，两个天线的谐振频率根据天线之间的空气间隙而变化。为了使用该系统实现最大效率，天线的谐振频率和系统的频率必须匹配。然而，当该技术应用于MHz范围（允许小型天线）时，可用频率受工业、科学和医疗（ISM）频带的限制。因此，需要一种将谐振频率固定在ISM频带内的方法。本文研究了利用阻抗匹配网络将相距一定距离的一对天线的谐振频率调节到13.56MHz的可能性。通过等效电路、电磁场分析和实验研究了天线的电特性。利用等效电路作为参考，计算了IM电路的参数。仿真和实验结果表明，对于不同的气隙，IM电路可以将谐振频率改变到13.56MHz，从而提高功率传输效率。
Wireless power transfer is essential for the spread of Electric Vehicle(EV) usage as it provides a safe and convenient way to charge the EVs. Recently, a highly efficient mid-range wireless power transfer technology using electromagnetic resonance coupling, WiTricity, was proposed. Studies show that the resonant frequencies of the two antennas change according to the air gap in between the antennas. To achieve maximum efficiency using this system, the resonance frequencies of the antennas and the frequency of the system has to be matched. However, when this technology is applied in the MHz range (which allows small sized antennas), the usable frequency is bounded by the Industrial, Scientific, and Medical(ISM) band. Hence a method to fix the resonance frequency within the ISM band is required. In this paper, the possibility of using impedance matching (IM) networks to adjust the resonance frequency of a pair of antennas at a certain distance to 13.56MHz is studied. We studied the electrical characteristics of the antenna with equivalent circuits, electromagnetic analysis and experiments. The equivalent circuits are used as reference to calculate the parameters of the IM circuits. The simulations and experiments shows that the IM circuits can change the resonance frequency to 13.56MHz for different air gaps, thus improving the power transfer efficiency.