A Wireless Power Transfer System With Hybrid Control for Constant Current and Voltage Output

This article proposes the wireless power transfer (WPT) system that achieves both inherent constant current and constant voltage (CV) outputs by switching the fixed frequency control strategy and the self-oscillating control strategy. Initially, the proposed system is analyzed by the
$M$
model, and the transmission performance of the proposed WPT system under different control strategies is studied. The output voltage of the proposed system in the CV mode is not only independent of the load resistance but also irrespective of the coupling coefficient; hence, the system has a high misalignment tolerance. Moreover, a method for estimating parameters is presented, and this approach can monitor the load resistance and coupling coefficient only by detecting the primary side current, and the proposed system does not require wireless communication. The workflow of the system is designed. Finally, the feasibility of the proposed method is verified by the experimental results obtained from the laboratory prototype.