Design and Implementation of a Constant Current and Constant Voltage Wireless Charger Operating at 6.78 MHz

Recently wireless Power Transfer (WPT) has received a great interest due to its advantages such as better user convenience and better safety as compared to the conventional charger with cord. In a WPT charging system operating at MHz range, a DC/DC converter to provide the accurate voltage and current to the battery for its safety. This paper presents about the design and implementation of a high frequency class D Wireless Power Transfer system which makes it possible to charge the Lithium Batteries by the Constant Current (CC) and Constant Voltage (CV) Charge with a pair of coil. Since the charger can provide automatic transfer from CC to CV charge, the battery can be fully charged without the help of an additional DC/DC converter. The simulation and 50W-6.78-MHz hardware experimental results are presented to verify the feasibility of the proposed method and to evaluate the performance of the proposed wireless battery charger.