MMC-HVDC系统冗余容错模型预测控制  

Redundancy Fault-Tolerant Based Model Predict Control of MMC-HVDC System

作　　者：刘英培[1] 杨海悦 梁海平[1] 王敬海[2] 王正平 赵玮 

机构地区：[1]华北电力大学电气与电子工程学院,河北省保定市071003 [2]国网潍坊供电公司,山东省潍坊市261041 [3]国网沧州供电分公司,河北省沧州市061001

出　　处：《电网技术》2017年第8期2443-2454,共12页Power System Technology

基　　金：国家自然科学基金(51607069);河北省自然科学基金(E2015502012);中央高校基本科研业务费专项基金资助(2016MS88;2017MS091)~~

摘　　要：当模块化多电平换流器柔性直流(modular multilevel converter-high voltage direct current,MMC-HVDC)输电系统子模块发生故障时,上、下桥臂处于不对称运行状态,此时会导致上、下桥臂子模块输出电压之和不均衡,造成换流器内部环流不仅含有二倍频负序分量,还增加了基频分量,导致直流侧电流波动。基于MMC桥臂子模块不对称运行时平均开关函数,阐述了上下桥臂子模块数目不对称运行时子模块数量不对称所在相上、下桥臂子模块输出电压之和,以及桥臂电流基频分量与桥臂正常运行子模块数量、环流直流分量和二倍频分量之间的关系。提出一种MMC-HVDC系统冗余容错模型预测控制策略,在实现交流电流跟踪、子模块电容电压均衡的同时,可以实现故障时对环流基频和二倍频成分的抑制,使正常运行子模块电压维持在给定值附近,维持直流侧电流稳定。仿真结果验证了所提控制策略的可行性和有效性。When a sub-module fails in modular multilevel converter based high voltage direct current （MMC-HVDC） transmission system, upper and lower bridge-arms of the converter are under unbalance operation condition, and MMC circulating current contains not only second-order negative-sequence component, but also fundamental-frequency component, thus leading to current fluctuation in DC side. This article stated output sum voltage of upper and lower bridge-arms of unbalanced sub-module based on average switch function. In this paper, relationship between fundamental component of bridge-arm current, number of normal sub-modules and DC and second-order components of bridge-arm current was analyzed. Redundancy fault-tolerant model prediction control strategy of MMC-HVDC transmission system was presented. It can achieve not only tracking AC side current and balancing sub-module voltage, but also suppressing fundamental and second-order component of circulating current. In addition, this strategy can maintain sub-module voltage around its reference value and DC side current steadily. Simulation results validated feasibility and effectiveness of the proposed control strategy.

关 键 词：模块化多电平换流器柔性直流输电系统 冗余容错 模型预测控制 环流抑制 

分 类 号：TM72[电气工程—电力系统及自动化]