The design of auxiliary power supply (APS) in solid-state transformers (SSTs) is quite challenging. To minimize the isolation requirement, this APS is usually powered by dc-link capacitors. However, it poses voltage unbalance issues when the main converter is not in operation. To address this problem, a compact and cost-effective APS design is proposed, which utilizes the isolation structure of main medium-frequency transformers (MFTs). The proposed APS system also provides half-duplex communication, which replaces the costly optical fiber system. The interference between main and auxiliary power transfer links has been significantly reduced by the decoupled transformer design and the dual-band scheme for inductor-inductor-capacitor (LLC) and inductor-capacitor-inductor-capacitor (LCLC) converters. In addition, a new startup strategy with a low standby power is applied to this APS system. A 3.2-kW SST prototype with a peak efficiency of 97.9% has been built, whose APS is 6 W. The experimental results verify the feasibility and performance of the proposed techniques.

中文翻译：

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一种紧凑型中频固态变压器辅助电源设计


固态变压器（SST）中的辅助电源（APS）的设计非常具有挑战性。为了最大限度地降低隔离要求，该 APS 通常由直流母线电容器供电。然而，当主转换器不运行时，它会带来电压不平衡问题。为了解决这个问题，提出了一种紧凑且经济高效的 APS 设计，该设计利用主中频变压器 (MFT) 的隔离结构。所提出的 APS 系统还提供半双工通信，取代了昂贵的光纤系统。通过解耦变压器设计以及电感-电感-电容（LLC）和电感-电容-电感-电容（LCLC）转换器的双频段方案，显着降低了主辅助功率传输链路之间的干扰。此外，该APS系统还采用了新的低待机功耗启动策略。搭建了峰值效率为 97.9% 的 3.2 kW SST 原型机，APS 为 6 W。实验结果验证了所提技术的可行性和性能。