柔性直流配电系统高频振荡降阶模型与机理分析

在柔性直流配电系统中，由于存在多时间尺度的控制环节和物理电路相互作用的影响，容易产生高频振荡现象。文中针对柔性直流配电系统的高频振荡机理进行研究，建立了柔性直流配电系统高阶数学模型，通过对影响系统阶数的关键参数灵敏度分析实现系统降阶，推导了时域下系统参数对高频振荡频率影响的解析式，文中总结了直流侧滤波电容、交流侧等效电感和控制器参数对高频振荡的影响规律。最后，基于Simulink搭建了低压和中压柔性直流配电系统的仿真模型，仿真结果验证了理论分析的有效性。

Reduced-order Model and Mechanism Analysis of High-frequency Oscillation in Flexible DC Distribution System

High-frequency oscillation is frequently occurs in flexible DC distribution systems, due to the influence of the interaction of multiple time scale control links and physical circuits. This paper studies the mechanism of high-frequency oscillation, and establishes a high-order mathematical model of the flexible DC distribution system. Sensitivity analysis of the key parameters affecting the system order has been conducted to realize the model order reduction. The analytical equation of high-frequency oscillation is deduced in time domain considering the influence of system parameters. This paper summarizes the influence law of the DC side filter capacitor, AC side equivalent inductance and controller parameters on high-frequency oscillation. Finally, based on Simulink, the simulation models of low-voltage and medium-voltage flexible DC distribution systems are built, and the simulation results verify the validity of the theoretical analysis.