A Primary-Side Fixed-Frequency CC and CV Output Control for Single-Stage Wireless Battery Chargers With Series Compensation Receivers

This article presents a generalized primary-side control strategy in achieving constant current (CC) and constant voltage (CV) for wireless battery chargers (WBCs) with series-compensated receivers, while extra battery management circuits are not required. The proposed control is applicable to wireless power transfer (WPT) systems with any compensation networks (X) at the primary side. Unlike conventional CC and CV charging of battery loads in single-stage series–series (SS)-compensated WBCs using frequency modulations, the proposed scheme allows constant frequency operations for XS-compensated WBCs without communication feedback. The proposed control strategy is established based on a novel communication-free front-end monitoring scheme for static mutual inductances using two nonresonant frequencies. Both the simulation and practical results of a popular XS-compensated (i.e., LCC-S) WPT system are presented to validate the effectiveness of the new transmitter-side CC and CV charging strategy for XS-compensated WBCs with minimal receiver-side designs. The accuracies of the intermediate static mutual inductance identification scheme are also verified.