Wireless power transfer system for capsule endoscopy based on strongly coupled magnetic resonance theory

Capsule endoscopy is a new technique that allows complete exploration of the small intestine, and widely used all over the world, for its convenience and less pains compared with traditional endoscopy. However, the limited power supplies of batteries handicap the development of capsule endoscopy. This paper presents a novel wireless power transfer system for the capsule endoscopy utilizing the strongly coupled magnetic resonances theory. The wireless power transfer system consists of four coils, an excitation source and a load. In order to evaluate the system performance, experiments were carried out in which the working frequency is determined at 8.2MHz. The results demonstrate that the distance between two sets of transmission coils have great effect on the system efficiency and the maximal system efficiency can reach 26.14%. Therefore, this power supply system has a promising prospect on wireless power transfer for capsule endoscopy. Improving the quality factor of coils can effectively increase the efficiency of the system, which is the key to the future work.