In megahertz (MHz) wireless power transfer (WPT) systems, a varying reflected reactance due to a changing final load deteriorates the overall system performance, such as efficiency and output voltage stability. This article aims to achieve a compact and robust MHz WPT system working over a wide range of load. A novel concept of reactance compression design is proposed to compress the variation of the reflected reactance through positioning of a “reactance window.” Efficient receiving-side parameter design procedures are then developed to best compress the reactance variation and satisfy maximum output power requirement in a wide load range but without adding any other hardware. This makes it possible to directly apply the existing voltage-source design using a modified Class E power amplifier (PA) and current-source design using an LCC transformation network. An edge inductor also becomes worthy to replace the bulky air-core infinite inductor required by the modified Class E PA, thereby further improving circuit compactness. Finally, the receiving-side design concept and the edge inductor are experimentally implemented to verify their performance over a 5–50- $\Omega$ load and with the maximum final output power of 20 W. The results well validate the improved reactance compression, output voltage stability, efficiency, and harmonic distortions over the wide load range.

中文翻译：

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基于新型电抗压缩设计和边缘电感器的宽负载范围和紧凑型 MHz 无线电力传输系统

在兆赫 (MHz) 无线电力传输 (WPT) 系统中，由于最终负载变化而导致的反射电抗变化会降低整体系统性能，例如效率和输出电压稳定性。本文旨在实现一个紧凑而强大的 MHz WPT 系统，可在广泛的负载范围内工作。提出了一种电抗压缩设计的新概念，通过定位“电抗窗口”来压缩反射电抗的变化。然后开发有效的接收侧参数设计程序，以最好地压缩电抗变化并满足宽负载范围内的最大输出功率要求，但不添加任何其他硬件。这使得使用改进的 E 类功率放大器 (PA) 和电流源设计直接应用现有电压源设计成为可能。低成本航空公司转换网络。边缘电感也值得替代改良的 E 类 PA 所需的笨重空芯无限电感，从而进一步提高电路的紧凑性。最后，通过实验实现接收侧设计概念和边缘电感器，以验证它们在 5-50- $\欧米茄$ 负载和最大最终输出功率为 20 W。结果很好地验证了在宽负载范围内改进的电抗压缩、输出电压稳定性、效率和谐波失真。