Sizing Wireless Battery Charger for the CC-CV Charging of Lithium Polymer Battery Used in Unmanned Aerial Vehicle

This paper explores the design of a wireless battery charger using the Series-Series Resonant Inductive Power Transfer (SS-RIPT) technique for the charging of Lithium Polymer (LiPo) batteries in Unmanned Aerial Vehicles (UAVs). The charger utilizes the popular Constant Current-Constant Voltage (CC-CV) charging method and aims to ensure the appropriate component ratings for fabrication. The paper describes an analytical approach for sizing the components of the charger such as inductors and capacitors values of the resonant inductive circuit, taking into account the impact of load and coupling variations on voltage and current stress in the circuit. The results of the simulation in the LTspice tool are used to validate the analytical calculations. A behavioral model of LiPo battery has been created to apply the load seen by charger during CC-CV operation. A closed-loop controller with a fixed frequency and a variable duty cycle on the primary side has been used to control the output voltage and current during the CC-CV charging process.