Wireless Charger

Abstract

Wireless Power Transfer (WPT) is to transmit energy from a source to the load without wire; it is very useful when wire is not available or inconvenient to set up. Since there isn’t any wire to connect the primary circuit and the load, the efficiency would be a critical problem of WPT. In this project, the efficiency, principle and the implementation of Inductive Power Transfer (IPT) and Capacitive Power Transfer (CPT) would be investigated and see which one would give a better performance on a certain application. IPT makes use of two coils with several turns to generate magnetic field to transfer power from primary coil to secondary coil. CPT makes use of two conductive plates to generate an electric field in order to transfer power to the load. Moreover, a whole Wireless Power Transfer System would be built including a Power Amplifier, Wireless Power Transfer and Rectifying circuit. All the components would be combined into two products (transmitter and receiver). The result shows that CPT gives a better performance than IPT in terms of distance, alignment and efficiency. And the efficiency of the Capacitive Power Transfer System is about 20-35% if a 3mm pig skin is separate between two capacitive plates.