基于耗散性的固态变压器多端口稳定性根本原因识别与缓解
Dissipativity-Based Multiport Stability Root-Cause Identification and Mitigation for Solid-State Transformers
浏览论文内容
中文总结 AI 辅助
针对高功率并网固态变压器控制回路设计不当致低频振荡问题，建立多端口导纳矩阵，通过多端口耗散性分析诊断不稳定根源，设计稳定控制器解决问题，在缩小比例原型上验证，有效保证弱电网下稳定运行。
中文摘要 AI 辅助
对于高功率并网应用中的固态变压器（SST），设计不当的控制回路会激发强烈的交直流端口耦合，导致低频振荡问题，尤其在弱电网条件下。本文建立了包含SST交流dq轴和初级直流端口的多端口导纳矩阵来表征其固有动态特性。通过多端口耗散性分析评估SST的鲁棒稳定性，利用将无源性条件分解为自耗散和耦合耗散指标来诊断不稳定的具体根本原因。发现同步回路内部动态引起的严重耦合耗散失效是主要不稳定机制。据此设计了具有无动态正交信号重构的稳定控制器来重塑SST的导纳特性，解决不稳定根源。最后在缩小比例的SST原型上验证了稳定性分析和增强策略的有效性，实验结果表明该准则能准确预测耦合振荡，增强控制器能保证在弱电网条件下稳定运行。
英文摘要
For solid-state transformers (SSTs) in high-power grid-connected applications, improperly designed control loops can excite strong inherent AC-DC port coupling, leading to low-frequency oscillation issues, especially under weak grid conditions. To address this problem, this article establishes a multiport admittance matrix for the SST, encompassing its AC dq axes and primary DC port, to characterize its inherent dynamics. Subsequently, a multiport dissipativity analysis is conducted to evaluate the robust stability of the SST. By leveraging the decomposition of passivity conditions into distinct self- and coupling-dissipativity indices, the specific root causes of instability are diagnosed. This framework reveals that a severe coupling-dissipativity failure, induced by the internal dynamics of the synchronization loop, is the dominant instability mechanism rather than a localized self-dissipativity issue. Guided by this diagnosis, a stabilizing controller featuring dynamics-free orthogonal signal reconstruction is designed to reshape the admittance characteristics of the SST. This enhancement specifically targets the identified coupling-dissipativity deficiencies, thereby resolving the root cause of the instability. Finally, the stability analysis and the effectiveness of the enhancement strategy are validated on a down-scaled SST prototype. Experimental results demonstrate that the criterion accurately predicts the coupling-induced oscillations and that the enhanced controller guarantees stable operation under challenging weak-grid conditions.
