使用線圈形式共振器之無線充電系統

Abstract

本論文提出應用於13.56MHz無線傳輸之印刷螺旋式線圈。由於傳統線圈放置於金屬平面旁，會有渦電流產生於金屬平面上，使整體的傳輸效率下降。在有金屬平面的情況，由於傳統電磁感應線圈會有很大的渦電流，於是為了降低渦電流，採用了電磁共振的技術來實現。藉由增加一個螺旋共振器，不但可減小渦電流的產生，還能因利用了超穎材料(metamaterial)來提升傳輸效率，從量測結果可得與傳統電磁感應技術的螺旋式線圈相比，傳輸效率會由3.7%提升至31.4%，接著並將結構應用於平移及角度變化，比較結果。而藉著在螺旋共振器上加入單刀四擲開關(SP4T)，可輕易的將偏移的工作頻率調整回13.56MHz而不需要調整匹配電路。這裡利用當金屬導體與線圈間的距離改變，來使工作頻率產生偏移。最後，可比較製作完成之線圈的模擬及量測結果來驗證本論文架構。

This thesis proposes 13.56MHz coil for wireless power transfer application. When the metal plate is placed near the coil, eddy current will be induced on the metal plate to decrease the transmission efficiency. In magnetic induction mechanism, huge eddy current will be induced on metal plate. Magnetic resonance mechanism is proposed to reduce the eddy current. By adding the spiral resonator, it not only reduces the eddy current, but also improves the transmission efficiency by using metamaterial. The measurement result shows that the transmission efficiency will be increased from 3.7% to 31.4% as compared to the traditional magnetic induction coil. Moreover, the lateral and angular misalignment effects of the proposed structure are investigated. By utilizing the SP4T switch on the spiral resonator, the shifted operating frequency can be easily adjusted back to 13.56MHz without any variation on the matching circuit. The distance between coil and metal plate is changed to examine the variation of operating frequency. Finally, the simulated and measured results of fabricated coils are compared to validate the proposed structure.