摘要
分析模块化多电平换流器(modular multilevel converter,MMC)交直流侧呈现的阻抗频率特性是系统设计的重要内容。首先根据MMC的基本运行机理和连续模型,推导交直流侧阻抗的等效表达公式;然后提出基于测试信号法的阻抗计算方法和详细实现流程;最后利用PSCAD/EMTDC对典型系统进行仿真计算。结果表明:1)在电压源激励和电流源激励下所呈现的交流侧阻抗特性不同,而直流侧阻抗特性一致;2)交流侧阻抗特性难以利用无源元件简单串并联模拟,而直流侧阻抗可等效为单调谐滤波器;3)稳态运行点变化对交直流侧阻抗几乎没有影响;4)不同控制模式下交直流阻抗特性曲线基本趋势一致,主要在低频范围内略有不同。
Analysis on the AC/DC side impedance- frequency characteristics of the modular multilevel converter （MMC） is one of the most important issues in system design. Firstly, the equivalent formulas of the AC/DC side impedance are derived based on the operation mechanism and continuous model of the MMC. Secondly, an impedance calculation approach adoioting Test Signal Method is proposed, and its detailed implementation process is presented. Finally, based on the suggested approach, the AC/DC side impedance-frequency characteristics of a typical MMC-HVDC system are calculated and analyzed in the PSCAD/EMTDC software. The main results include： 1） the AC side impedances derived by the voltage excitation source and the current excitation source achieve different characteristics, however, the DC side impedances derived by different excitation sources are the same; 2） the AC side impedance is difficult to be simulated by a simple series-parallel passive components, however, the DC side impedance characteristic can be equivalent to the characteristic of a single-tuned filter; 3） changing in steady-state operating points does no effects on the AC/DC side impedance; 4） under different control modes, the main trends of the AC/DC side impedance characteristic curves are almost the same, however, which are different mainly in the low frequency range.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2014年第24期4040-4048,共9页
Proceedings of the CSEE
基金
国家863高技术基金项目(2012AA050205)~~
关键词
模块化多电平换流器
时域仿真
阻抗频率特性
测试信号法
modular multilevel converter （MMC）
timedomain simulation
impedance-frequency characteristic
testsignal method
