3-Coil orientation insensitive wireless power transfer for capsule endoscope

To decrease the variation range of the received DC voltage and wireless power transfer efficiency in capsule endoscopy system, in this paper, a new method is presented. Three orthogonal coils, overlapped partially, are used to receive magnetic power, then sum of rectified voltages delivered to load through series rectifiers. The implemented system can transfer power up to 39 mW and prepare 3.6 V for capsule subsystems. Remarkably, the variation ranges of output DC voltage and power efficiency are less than 12% and 19%, respectively.