A novel wireless power transfer system with two parallel opposed coils for gastrointestinal capsule robot

Abstract This paper proposes a wireless power transfer (WPT) system with two parallel opposed coils for powering capsule robot (CR) or other implantable medical devices, where the power cable is inconvenient. The novel WPT system can obviously improve the low power transfer efficiency (PTE) and poor power transfer stability (PTS), which are the key limitations of WPT system in this application conventionally. The transmitting coils (TC) of the proposed WPT system are arranged up and down, and the magnetic cores are embedded inside the coils for the first time. In addition, benefiting from the up-down structure of the TCs, the coil spacing can be adjusted according to the patients’ body size. As a result, the PTS and PTE are significantly improved. In this paper, the theoretical model of the proposed WPT system is established and analyzed by finite element simulation. To verify the effectiveness of the proposed design, we conducted experimental tests on PTE and PTS, and an in-vitro experiments for prototype of the WPT system with CR was carried out. The experimental results demonstrate that the proposed WPT system achieves PTE of 8.68 % and PTS of 94.24 %, which is a notable improvement in the WPT system for CR.