A Hybrid Topology Relay Based Wireless Power Transfer System With Mutual Inductance Enhancement and High Misalignment Tolerance

A wireless power transfer (WPT) system based on a hybrid topology relay is proposed to enhance mutual inductance (MI) and improve misalignment tolerance in this letter. First, the system with hybrid topology relay is proposed and the relay coil is integrated on the receiving side. Second, two adjustment factors <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</i> are generated by introducing the hybrid topology relay, where <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</i> is mainly used to design the equivalent MI value and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</i> is mainly applied to adjust the fluctuation of the equivalent MI. As a result, equivalent MI can be enhanced, and misalignment tolerance can be also optimized and improved. In addition, the power transmission capability can also be improved because the transconductance gain is proportional to the equivalent MI. Finally, the experimental setup, with a power output of 3.3 kW, is constructed. The constant current output characteristic and high misalignment tolerance are verified. The results show that the dc–dc efficiency is higher than 93.05% within the 100 mm horizontal misalignment range, and the fluctuation percentage of the equivalent MI is only 4.89%.