两电平VSC与MMC通用型平均值仿真模型

提出了两电平电压源型换流器(VSC)与模块化多电平换流器(MMC)的通用型平均值仿真模型。首先总结了两电平VSC与MMC的工作原理,进而理论推导了两者的平均值模型,通过分析两电平VSC与MMC在直流故障下的响应,提出了一种能仿真两电平VSC和MMC直流故障响应的通用建模方法。随后在PSCAD/EMTDC下搭建了一个两电平VSC与21电平MMC的详细电磁暂态仿真模型与平均值模型,对比验证了详细模型与平均值模型在稳态运行、直流故障以及交流故障下的响应。结果表明,所提出的平均值模型能在稳态运行、直流故障以及交流故障下得到与详细模型高度吻合的仿真结果。所提出的平均值模型能极大地提高仿真速度,且提速效果随电平数以及系统规模的增大而愈加明显。所提出的建模方法适用于研究含多个VSC和MMC的较大规模电力系统电磁暂态特性。

Generic Averaged Value Models for Two-level VSC and MMC

Generic averaged value models for two-level voltage source converter (VSC) and modular multilevel converter (MMC) are proposed. A brief summary of the operating principles of two-level VSC and MMC is given first, followed by theoretical derivation of averaged value models for two-level VSC and MMC. By analyzing the DC fault response of two-level VSC and MMC, a unified modeling method that is able to simulate DC fault response for two-level VSC and MMC is proposed. Detailed switching models and the proposed averaged models of two-level VSC and MMC are built in PSCAD/EMTDC. Responses of detailed models and averaged models during steady-state operation, DC fault and AC fault are compared and verified. The results show that the averaged models are able to generate identical fundamental results as the detailed switching models while significantly improving simulation speed. The proposed averaged models are suitable for fast simulating the electro-magnetic transients of large grids incorporating numerous VSCs and MMCs. This work is supported by National Natural Science Foundation of China (No. 51377067, No. 51261130484) and State Grid Corporation of China Under the Contract State Grid Research (No. 2013-304).