This paper introduces a new direct step-up ac-ac converter designed based on the SEPIC. It provides a higher step-up conversion ratio than other counterparts with valuable features like high efficiency, reasonable input and output total harmonic distortions (THD), continuous input current waveform, common ground, few components, and single-stage conversion without snubber and LC filters. Unlike most counterparts, the duty cycle can be varied between zero and one in boost operation and is not limited to any value below one. The voltage stress on one switch is reduced by increasing the winding coefficient of the utilized coupled inductor, and current stress on another is independent of this coefficient. It reduces the switches' losses and improves the converter efficiency. Thanks to the above attributes, the proposed converter is suitable for inductive power transfer from low-voltage ac sources, operating as an ac voltage regulator for sensitive ac loads, and any applications that require a boost converter with few components. This article shows the converter's operation principle and evaluates its performance through experiments on a 225 W prototype. Accordingly, the maximum obtained efficiency is 95.4%. The input and output current THDs for the nominal inductive load equal 4.5 and 2.8%, respectively. Results confirm the claims.

中文翻译：

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基于 SEPIC 的具有最佳元件数量的高升压直接 AC-AC 升压转换器

本文介绍了一种基于SEPIC设计的新型直接升压AC-AC转换器。它提供了比其他同类产品更高的升压转换比，具有高效率、合理的输入和输出总谐波失真 (THD)、连续输入电流波形、共地、元件少、无需缓冲器和 LC 的单级转换等宝贵特性过滤器。与大多数对应物不同的是，在升压操作中占空比可以在零和一之间变化，并且不限于低于一的任何值。通过增加所用耦合电感器的绕组系数可以降低一个开关上的电压应力，而另一个开关上的电流应力与该系数无关。它减少了开关损耗并提高了转换器效率。由于上述属性，所提出的转换器适用于低压交流电源的感应功率传输，作为敏感交流负载的交流电压调节器，以及任何需要带有少量组件的升压转换器的应用。本文展示了转换器的工作原理，并通过 225 W 原型机上的实验评估其性能。因此，获得的最大效率为95.4%。标称感性负载的输入和输出电流 THD 分别等于 4.5% 和 2.8%。结果证实了这一说法。