AI 中文总结
本文针对数据中心LLC型固态变压器的故障电流问题，提出嵌入DC-DC级控制的限流与恢复策略，经实验验证该策略可实现快速低成本的故障响应，适用于弹性数据中心电力架构。
AI 中文摘要
固态变压器（Solid-State Transformer, SST）因具备灵活的功率流和快速的动态响应，正日益被提议作为配电网与数据中心之间的接口。然而，当负载支路发生短路故障时，带有电压源型DC-DC级的SST会因故障电流而被迫关闭。因此，亟需限流策略，通过即时限制巨大的电流尖峰，并为故障支路的保护装置提供充足电流以使其动作，从而防止灾难性的设备损坏和级联停电。本文提出一种协调式直流负载容错限流与恢复策略，该策略直接嵌入SST的DC-DC级控制中，无需额外硬件成本。具体而言，研究了示例LLC谐振变换器的故障机理；据此实现了故障检测框架，提出了一种闭环电流控制器，通过提升开关频率并调整占空比，在微秒级内将直流电流限制至指定值；随后，在故障隔离后，采用斜坡恢复阶段恢复直流母线，且不会产生浪涌电流。在LLC变换器原型上开展的实验验证了所提限流策略的可行性，可实现更快、成本更低的故障响应，适用于弹性数据中心电力架构。
英文摘要
Solid-State Transformers (SSTs) are increasingly proposed as the interface between distribution grids and data centers due to flexible power flows and fast dynamic response. However, when a short-circuit fault occurs in a load branch, the SST with a voltage-source-type DC-DC stage is forced to shut down due to fault currents. Therefore, current-limiting strategies are strongly needed to prevent catastrophic equipment damage and cascading blackouts by instantly restricting massive current spikes and offering sufficient currents for protection devices to act at the faulted branch. This paper proposes a coordinated DC load fault-tolerant current-limiting and recovery strategy embedded directly in the control of the SST DC-DC stage, avoiding additional hardware cost. Specifically, the fault mechanism of an example LLC resonant converter is studied. Accordingly, a fault detection framework is implemented, a closed-loop current controller is proposed to limit the DC current to a designated value within microseconds by surging the switching frequency and adjusting the duty cycle, and a ramped recovery stage will then restore the DC bus after the fault isolation without inrush currents. Experiments on an LLC converter prototype have verified the feasibility of the proposed current-limiting strategy, enabling faster and lower-cost fault response suitable for resilient data center power architectures.
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