基于小信号谐波模型的VSC换流器谐波特性分析

Analysis of Harmonic Characteristics of the VSC Converter Based on a Small Signal Harmonic Model

为了准确分析电压源换流器(voltage source converter,VSC)中稳态谐波特性,基于谐波状态空间(harmonic state space,HSS)理论,在稳态运行点处建立了小信号VSC-HSS模型,推导了VSC-HSS的谐波传递函数矩阵。VSC-HSS模型计算结果得到的时域波形及频域谐波含量与仿真结果一致,谐波传递函数得到的耦合导纳反映了VSC换流器的谐波耦合特性。VSC-HSS模型具有传统建模方法不具有的描述谐波分量的特性,谐波传递函数可用于分析稳态下换流器输入中含平衡或不平衡谐波时的谐波特性,方法可推广到各类电力电子换流器的谐波特性分析中。

In order to accurately analyze steady-state harmonic characteristics of the voltage source converter(VSC),based on the harmonic state space(HSS)theory,a small-signal VSC-HSS model was established at the steady-state operating point,and the harmonic transfer function matrix of VSC-HSS was derived.The time domain waveform and frequency domain harmonic content obtained from the calculation results of the VSC-HSS model were consistent with the simulation results,and the coupling admittance obtained from the harmonic transfer function reflected the harmonic coupling characteristics of the VSC converter.The VSC-HSS model had the characteristic of describing harmonic components that the traditional modeling method did not have.The harmonic transfer function could be used to analyze harmonic characteristics when balanced or unbalanced harmonics were contained in the input of the converter in its steady state.The proposed approach could be extended to the analysis of harmonic characteristics of various power electronic converters.