Compact Wireless Power Transfer With Enhanced Misalignment Tolerance via Independent Secondary PWM Control
Xingpeng Yu, Ronghuan Xie, Yuexing Tu, Yizhan Zhuang, Xiangpeng Cheng, Fanghui Yin, Yiming Zhang
Abstract
Improving power density and system integration is a pivotal focus for wireless power transfer (WPT) in portable devices. However, challenges such as misalignment tolerance and power fluctuation persist. This letter introduces a robust solution utilizing secondary independent PWM control. A coil structure combining solenoids and reverse windings ensures passive misalignment tolerance, while a grooved magnetic core integrates the converter, optimizing compactness. Additionally, the secondary PWM control achieves precise output voltage regulation without communication. A high-power-density WPT prototype validates the proposed coupler and control method, demonstrating less than 1% output voltage fluctuation under a 50% misalignment and maintaining over 89% efficiency at 100 W. The secondary device is highly compact, measuring only 60 mm × 30 mm × 7.5 mm and achieving power density of 7.41 W/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>.