A High-Efficiency Wireless Power Transfer Converter with Integrated Power Stages

For wireless power transfer (WPT) systems, loads and coupling coefficients are subject to change, which adversely affects the efficiency and stability of the system. To address this vital problem, in this article, a WPT system based on topology integration and its control strategy is proposed. Compared with the traditional maximum efficiency point tracking (MEPT) systems, the proposed system reduces the use of dc-dc converters through the power switch integration technique, thereby avoiding additional losses due to the extra power stage. Then, by analyzing the output characteristics of the proposed WPT system, an implementation of MEPT based on pulse width modulation (PWM) can be presented. An experimental prototype is built to verify the feasibility of the proposed method. Experimental results show that the proposed method can maintain a constant output voltage, realize the MEPT and zero-voltage-switching (ZVS) operation, with high efficiencies up to 96.19% in a wide load range.