Abstract: Providing reliable and stable power is still the biggest technical obstacle to realize multifunctional capsule endoscopes. Aiming at the low efficiency of traditional Class D inverter, this paper designs a Class E wireless power transfer system for wireless capsule endoscopy. Firstly, the working principle of Class E wireless power supply system is introduced. Then the component parameters of Class E inverter are determined by combining the design formula and circuit simulation experiment. Finally, an experimental platform was built to verify the accuracy of the finite element simulation and evaluate the performance of the system in the center plane. Comparative experimental results show that the Class E wireless power transfer system is capable of delivering 781 mW of power when the receiving coil is located at the center, which significantly improves the power transfer efficiency from 5.39% to 7.81% compared with the Class D inverter. In addition, the receiving coil can continuously receive more than 500 mW of energy when operating at the center plane.

Key words: Wireless capsule endoscopy, Wireless power transfer, Class E inverter, Power transfer efficiency