Conventional active-clamp flyback (ACF) converters suffer increased conduction losses due to the extended conduction time of the auxiliary switch during light loads. To tackle this problem and improve light-load efficiency, this article proposes a novel control strategy. This strategy is designed to limit the generation of excessive conduction losses by the auxiliary switch during light loads. The proposed control strategy also employs the quasi-resonant (QR) valley switching (VS) technique within a single switching cycle to activate the auxiliary switch. This enables the main switch to achieve zero-voltage switching (ZVS) characteristics during its operation. Moreover, once the converter reaches medium loads, the auxiliary and main switches operate in a complementary manner with a fixed frequency. This operation allows both switches to achieve ZVS, leading to a significant reduction in switching losses. The operating principle and control strategy of the 65-W ACF converter with the novel control approach have been thoroughly analyzed and discussed. Experimental results have confirmed the effectiveness of this strategy, validating its ability to improve the overall efficiency of the converter under various load conditions.

中文翻译：

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开发有源钳位反激式转换器以提高轻负载效率


由于轻负载期间辅助开关的导通时间延长，传统的有源钳位反激式 (ACF) 转换器的导通损耗增加。为了解决这个问题并提高轻载效率，本文提出了一种新颖的控制策略。该策略旨在限制轻负载期间辅助开关产生过多的导通损耗。所提出的控制策略还在单个开关周期内采用准谐振（QR）谷底开关（VS）技术来激活辅助开关。这使得主开关在工作期间能够实现零电压开关（ZVS）特性。此外，一旦转换器达到中等负载，辅助开关和主开关就会以固定频率以互补方式运行。此操作允许两个开关实现 ZVS，从而显着降低开关损耗。对采用新颖控制方法的 65W ACF 转换器的工作原理和控制策略进行了深入分析和讨论。实验结果证实了该策略的有效性，验证了其在各种负载条件下提高转换器整体效率的能力。