A Vertically Modularized Reconfigurable Wireless Power Transfer System: Architecture, Modeling, and Design

It is known that megahertz (MHz) wireless power transfer (WPT) is particularly beneficial in terms of spatial freedom of power transfer and circuit compactness. Meanwhile, design complexity is a main obstacle to the spread of MHz WPT. In this article, a new modular design concept is proposed to conveniently reconfigure a MHz WPT system for different applications. Multiple predesigned functional unit modules can easily be combined to form a complete new WPT system with a different power level and transfer distance. A vertically stacked architecture is especially chosen to save space in actual applications. Detail analytical derivations are conducted to analyze the modular design, including the influence of different combinations of the unit modules. A new interleaved coil design is developed to reduce the proximity effect and cross coupling among the vertically stacked modules. Finally, the modular design concept is validated by experiments and demonstrates the desired scalability in both power levels and transfer distances. Through 15 combinations of the unit modules, the experimental WPT system can be reconfigured to provide an output power from 4 to 116 W. The effective transfer distance can be also extended from 30 to 90 mm and 80% system dc-dc efficiency is achieved within a 70-mm transfer distance using 100-mm-diameter printed circuit board coils.