Dynamic Monitoring of Battery Variables and Mutual Inductance for Primary-Side Control of a Wireless Charging System

Abstract

This article proposes a fast and accurate real-time estimation method for developing a dynamic battery circuit model on the primary side of a series–series (SS) compensated wireless power transfer (WPT) system. By detecting the current of the transmitter resonator only, the charging voltage, charging current, state-of-charge, the equivalent resistance of the Lithium-ion battery, and the mutual inductance in the WPT system can be accurately estimated in real time. The battery equivalent circuit can be transferred to the primary side. The constant-current and constant-voltage charging of the Li-ion battery can, therefore, be realized with primary-side control. The proposal has been successfully implemented and verified in a hardware setup with a Lithium-ion battery load. It provides a new tool to transfer the battery model to the primary side for future optimal primary-side control of SS-compensated WPT systems.