考虑相对误差和计算复杂度的MMC最佳等效仿真电平数的确定方法

发布时间：2018-03-09 15:05

本文选题：模块化多电平换流器　切入点：戴维南等效模型　出处：《中国电机工程学报》2016年07期 　论文类型：期刊论文

【摘要】：模块化多电平换流器(modular multilevel converter,MMC)已经展现出极其重要的工程应用前景,然而,即使采用超高电平数的MMC精确等效模型也无法满足未来直流电网的需求。因此,对MMC高效模型进行相对误差分析,以寻求满足特定模型精度和计算效率的等效仿真最佳电平数具有重要意义。文中以451电平MMC戴维南等效模型为基准,首先提出精确仿真不同电平MMC时的仿真步长计算方法。然后根据MMC等效模型与详细模型的仿真误差,采用基于测量所得客观权重的改进层次分析法,将各电气量的相对误差整合为该电平数下MMC的综合相对误差。在与基准模型电气参数相同的一系列电平数MMC中,分别仿真和计算得到稳态、交流系统暂态和直流系统暂态情况下的相对误差曲线,同时测量3种工况下各电平数MMC的仿真用时,采用归一化方法和曲线拟合,得到各工况下的最佳电平数。进而利用基于客观权重的层次分析法,根据不同场合对精度和效率的需求,得到不同权重比下的综合MMC等效仿真最佳电平数。最后,通过仿真算例验证最佳电平数MMC模型的合理性和有效性
[Abstract]:Modularized multilevel converter (Modular multilevel convertor MMC) has shown a very important prospect in engineering applications. However, even the accurate equivalent model of MMC with ultra high level number can not meet the needs of future DC networks. It is of great significance to analyze the relative error of MMC efficient model in order to find the optimal number of equivalent simulation levels that can satisfy the accuracy and computational efficiency of the specific model. The 451-level MMC Davinan equivalent model is used as the reference in this paper. In this paper, the method of calculating the simulation step size of MMC at different levels is proposed, and then, according to the simulation error between the MMC equivalent model and the detailed model, an improved analytic hierarchy process (AHP) based on the objective weight obtained from the measurement is adopted. The relative error of each electrical quantity is integrated into the comprehensive relative error of MMC at this level number. In a series of level number MMC with the same electrical parameters as the reference model, the steady state is obtained by simulation and calculation, respectively. The relative error curves of AC system transient state and DC system transient state are measured at the same time, and the simulation time of each level number MMC under three operating conditions is measured, and the normalized method and curve fitting are adopted. The optimum level number under different working conditions is obtained, and then the optimal level number of synthetic MMC equivalent simulation under different weight ratio is obtained by using AHP based on objective weight and according to the requirement of accuracy and efficiency in different situations. Finally, The rationality and validity of the optimal level number MMC model are verified by a simulation example.
【作者单位】：新能源电力系统国家重点实验室(华北电力大学);国网智能电网研究院;
【基金】：国家863高技术基金项目(2013AA050105) 中央高校基金(2015XS08) 国家电网公司专项千人计划支持项目([2014]264号)~~
【分类号】：TM721.1

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