题目/Title：A Two-Hop Wireless Power Transfer System With an Efficiency-Enhanced Power Receiver for Motion-Free Capsule Endoscopy Inspection

作者/Author：孙天佳,谢翔,李国林,谷荧柯,邓仰东,王志华
                        Tianjia Sun,Xiang Xie,Guolin Li,Yingke Gu,Yangdong Deng,Zhihua Wang

期刊/Journal：IEEE Transactions on Biomedical Engineering

年份/Issue Date：2012Nov.

卷（期）及页码/Volume（No.）&pages：Vol.59, No.11, pp. 3247 - 3254

摘要/Abstract：
This paper presents a wireless power transfer system for a motion-free capsule endoscopy inspection. Conventionally, a wireless power transmitter in a specifically designed jacket has to be connected to a strong power source with a long cable. To avoid the power cable and allow patients to walk freely in a room, this paper proposes a two-hop wireless power transfer system. First, power is transferred from a floor to a power relay in the patient’s jacket via strong-coupling. Next, power is delivered from the power relay to the capsule via loose-coupling. Besides making patients much more conformable, the proposed techniques eliminate the sources of reliability issues arisen from the moving cable and connectors. In the capsule, it is critical to enhance the power conversion efficiency. This paper develops a switch-mode rectifier (rectifying efficiency of 93.6%) and a power combination circuit (enhances combining efficiency by 18%). Thanks to the two-hop transfer mechanism and the novel circuit techniques, this system is able to transfer an average power of 24mW and a peak power of 90mW from the floor to a 13mm×27mm capsule over a distance of one meter with the maximum DC-to-DC power efficiency of 3.04%.