The application of wireless power transfer (WPT) technology in capsule endoscopes (CEs) holds great promise, due to the fact that current capsule endoscopes consume a substantial amount of electrical energy during HD video transmission, and their compact size does not allow for the installation of large-capacity batteries. This paper introduces a novel WPT system comprising a 3-dimensional transmitting coil (3DTC) and a 1-dimensional receiving coil (DRC). By integrating an Inertial Measurement Unit (IMU) sensor into the CE, the attitude data of the capsule is acquired, enabling the current control of 3DTC to adjust the magnetic field direction and facilitate charging in any orientation. The design process involves initial calculations and simulations of the 3DTC, followed by the development of the control circuit. Finally, WPT experiments are carried out on the constructed system, in which the average transmission power is about 1512.9 mW, and the maximum transmission efficiency is approximately 4.7% in the experiments.
