AI 中文总结
针对弱电网下数据中心供电不稳定问题，提出无PLL的VM-DPC策略，结合自适应无功支持，在SCR≤2时可维持稳定运行，保障动态IT负载供电。
AI 中文摘要
由于换流器主导网络的快速发展和高度动态的人工智能（AI）工作负载，数据中心电力系统日益面临弱电网工况。在集中式不间断电源（UPS）架构中，前端整流器持续处理输入的设施电力，其动态性能对于确保稳定运行和向信息技术（IT）设备可靠供电至关重要。在弱电网工况下，传统基于锁相环（PLL）的比例积分（PI）整流器控制器可能因换流器控制动态与电网阻抗之间的强相互作用而出现不稳定。本文使用MATLAB/Simulink开发的详细开关级模型研究了弱电网下集中式UPS数据中心系统的稳定性，并通过OPAL-RT平台进行了实时验证。为提高弱电网稳定性并改善换流器-电网相互作用，前端整流器采用了带自适应无功功率支持的电压调制直接功率控制（VM-DPC）策略。该方法直接调节有功和无功功率，无需PLL同步，且在IT负载快速变化时动态支持公共耦合点（PCC）电压。结果表明，在短路比（SCR）≤2的条件下，传统基于PI的整流器控制会变得不稳定，导致直流母线振荡和下游供电性能下降；相比之下，所提出的VM-DPC策略可恢复稳定运行，提高系统阻尼，并在弱电网工况下维持向高度动态IT负载的可靠电力传输。
英文摘要
Data center power systems are increasingly exposed to weak-grid conditions due to the rapid growth of converter-dominated networks and highly dynamic artificial intelligence (AI) workloads. In centralized uninterruptible power supply (UPS) architectures, the front-end rectifier continuously processes the incoming facility power, making its dynamic performance critical for ensuring stable operation and reliable power delivery to information technology (IT) equipment. Under weak-grid conditions, conventional phase-locked loop (PLL)-based proportional-integral (PI) rectifier controllers may exhibit instability due to strong interactions between converter control dynamics and grid impedance. This paper investigates the stability of centralized UPS data center systems operating under weak-grid conditions using a detailed switching-level model developed in MATLAB/Simulink and validated in real time using an OPAL-RT platform. To enhance weak-grid stability and improve converter-grid interaction, a voltage-modulated direct power control (VM-DPC) strategy with adaptive reactive power support is applied to the front-end rectifier. The proposed approach directly regulates active and reactive power without PLL synchronization while dynamically supporting the point of common coupling (PCC) voltage during rapid IT load variations. Results demonstrate that conventional PI-based rectifier control becomes unstable under SCR<=2 conditions, leading to dc-link oscillations and degradation of downstream power delivery. In contrast, the proposed VM-DPC strategy restores stable operation, improves system damping, and maintains reliable power transfer to highly dynamic IT loads under weak-grid operation.
