为了计算分析含电压源型换流器(VSC)的电网,基于VSC序分量动态相量谐波分析模型和Thevenin定理,采用电流控制电压源对VSC进行等效,得出了VSC的稳态等值电路。首先,在序分量动态相量谐波分析模型下解析分析VSC稳态运行特性和交直流侧相互作用关系,列写交直流电压电流的代数方程;其次,在代数方程化简的基础上,建立了VSC交流侧基波正序稳态等值电路模型和基波负序与3次谐波正序的联立等值电路模型;最后,利用Thevenin定理,分别建立了不对称下基波负序稳态等值电路模型与3次谐波正序稳态等值电路模型。与仿真计算比较表明,通过电流控制电压源形式构建的Thevenin等效电路能够在稳态条件下等效基波正序分量、基波负序分量和3次谐波正序分量在VSC交直流侧的相互作用,可有效简化VSC的非线性特性与复杂的运行特性,为含VSC电网的稳态潮流计算和谐波潮流计算奠定基础。
In order to analyze the power system equipped with voltage source converters (VSCs), we applied a harmonic analysis model based on the dynamic phasor sequence components (DPSCs) and Thevenin theorem to put forward the static equivalent circuit models of VSC, which are composed of current controlled voltage sources. After analyzing the static performance of VSC by algebraic equations, we built equivalent circuit models based on the algebraic equations, including an equivalent circuit model of the fundamental positive sequence and an equivalent circuit model considering the negative sequence and the third positive sequence components simultaneously. We also built a fundamental negative sequence model and the third positive sequence equivalent circuits based on Thevenin theorem. Comparison with the simulations indicates that the equivalent circuit models with the current controlled voltage sources can present the interaction of the fundamental positive sequence component, the fundamental negative sequence component, and the third harmonic positive sequence component between the AC side and DC side of VSC, and they efficiently simplify the non- linear and complex characteristics of VSC. The results can be further applied to the static analysis of power system equipped with VSCs.