孤岛模式下风电直流微电网小信号稳定性分析

摘要

The voltage stability detection based on impedance-ratio criterion is introduced into the DC microgrid with wind power,a small-signal model of DC microgrid with wind power is established and analyzed,and the expressions of output/input impedance is derived for each element.A small-signal control model in two-phase synchronous rotating coordinates system is derived in detail for wind-power element and the influences of key parameters on the DC-side output impedance is analyzed,such as bus voltage,cross-over frequency,etc.,based on which,the impedance-ratio models are built for DC micro-source and load sub-system to simulate and analyze the stability of cascading system.Simulative results show that the proposed method of stability analysis based on small-signal impedance ratio can be used to guide the design of DC microgrid with wind power.%将基于阻抗比判定系统电压稳定的方法引入风电直流微电网中,建立并分析系统小信号模型,推导各单元输出/输入阻抗表达式.对于风电单元,详细推导其在两相同步旋转坐标系下的小信号控制模型,分析母线电压、穿越频率等关键参数对直流端输出阻抗的影响.在此基础上,建立了直流微网源、负载子系统的阻抗比模型,对级联系统稳定性进行了仿真分析.仿真结果表明:所提小信号阻抗比稳定性分析方法对风电直流微电网系统参数设计具有一定的指导性.