重訪MIT磁共振無線傳能系統研究

Abstract

本論文重點介紹了基於螺旋線圈的無線電力傳輸系統。麻省理工學院的一個研究小組首先發展了這種情況，他們成功地在中距離傳輸高達60瓦的電力。在其架構中，功率傳輸發生在兩個諧振螺旋線圈之間，並從其中萃取出輸入和輸出功率。關於線圈，它們則操作在幾MHz的相同頻率。 在本研究中，作者首先通過網絡分析儀測量其回波損耗來萃取出線圈的自感以及雜散電容。利用這些參數和期望的諧振頻率，可以確定外部串聯電容器以形成串聯LC諧振電路。此外，通過調節外部電容器，可以測量線圈在諧振頻率處具有的交流電阻。相應地實現了諧振線圈的品質因素。 發射機和接收機之間各種距離的傳輸特性可通過實驗評估。值得注意的是，與麻省理工學院的架構不同，除了發送和接收線圈外，還增加了一個橋接線圈。有趣的是，可以有效地延長傳輸距離。

This thesis revisits the wireless power transmission system based on helix coils. Such a scenario was first developed by a research group at MIT; they successfully transmit electrical power up to 60 Watts at a middle range. In their architecture, the power transmission takes place between two resonant helix coils, where the input and output power was extracted from them. Regarding the coils, they are operated at the same frequency around several MHz. In this research, the author first extracts the self-inductance, stray capacitance of the coils by measuring its return loss via a vector network analyzer. With these parameters and the desired resonant frequency, one may determine the external series capacitor to form a series LC resonant circuit. Moreover, by adjusting the external capacitor, one may have the coil AC resistance at the measured resonant frequencies. The quality factor of the resonant coil was realized accordingly. The transmission characteristics for various distances between the transmitter and receiver are evaluated experimentally. Significantly, different from the MIT’s architecture, a bridge coil in addition to transmit and receive ones is added. Interestingly, one may effectively extend the transmission distance.