CC-CV Control of Wireless Battery Charger Based on Discrete-Time Small-Signal Model

This paper presents a comprehensive discrete-time model of a wireless battery charger used to implement constant current (CC) and constant voltage (CV) charging control of the battery. The control objectives pertinent to wireless charging are identified and represented as multiple control loops in a block diagram that aids in visualizing the interactions between different control aspects. The separation of bandwidth is highlighted as a method for decoupling different control loops. An exact discrete-time model of the charger is developed and linearized to obtain the plant models for CC and CV mode charging. The closed-loop control is designed and verified experimentally on a 200 W prototype under steady-state and dynamic conditions.