交流侧不对称故障下柔性直流输电系统优化控制研究  

Research on Optimal Control of MMC-HVDC System Under AC Side Asymmetric Fault

作　　者：夏向阳[1] 易海淦 夏天 石超 贺烨丹 刘代飞[2] 邓文华 王灿 XIA Xiangyang;YI Haigan;XIA Tian;SHI Chao;HE Yedan;LIU Daifei;DENG Wenhua;WANG Can(College of Electrical&Information Engineering,Changsha University of Science&Technology,Changsha 410114,China;College of Energy and Power Engineering,Changsha University of Science&Technology,Changsha 410114,China;Hunan Changgao High Voltage Switchgear Co.,Ltd.,Changsha 410001,China)

机构地区：[1]长沙理工大学电气与信息工程学院,湖南长沙410114 [2]长沙理工大学能源与动力工程学院,湖南长沙410114 [3]湖南长高高压开关有限公司,湖南长沙410001

出　　处：《湖南大学学报（自然科学版）》2022年第8期159-168,共10页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51977014);长沙市科技计划重大专项(kh2102007)。

摘　　要：基于模块化多电平S换流器的柔性直流输电系统(Modular Multi-level ConverterHigh Voltage Direct Current,MMC-HVDC)在交流电网发生不对称故障时,故障侧MMC的内部特性和系统运行都受到较大影响.基于MMC桥臂平均值模型,提出一种不对称工况下MMCHVDC系统的优化控制策略,增强柔性直流输电系统的故障穿越能力.该策略主要由交流侧电流控制和环流抑制两个部分组成,在交流侧利用基于双二阶广义积分器锁相环(Phase Locked Loop Based on Double Second Order Generalized Integrator,DSOGI-PLL),在不对称工况下精确提取电压电流的正负序分量,配合双矢量控制器抑制负序电流,实现交流侧三相电流平衡.在MMC内部采用由PI控制器和重复控制器串联组成的嵌入式重复控制器(Proportional Integral and Repetitive Control,PI-RC)抑制环流中的二倍频正负零序分量,实现直流侧功率的恒定传输.在MATLAB/Simulink软件中搭建MMC-HVDC系统仿真模型,验证了所提优化控制策略的有效性.The internal characteristics and system operation of MMC on the fault side are greatly affected when an asymmetric fault occurs in the AC power grid of MMC-HVDC based on a modular multilevel converter.Based on the average value model of the MMC bridge arm,this paper proposes an optimal control strategy for the MMC-HVDC system under asymmetric conditions,which enhances the fault ride-through capability of a flexible HVDC system.The strategy is mainly composed of two parts:AC current measurement control and circulating current suppression.On the AC side,the phase-locked loop based on a double second order generalized integrator(DSOGI-PLL)is used to extract the positive and negative sequence components of voltage and current accurately under asymmetric conditions,and the negative sequence current is suppressed with a double vector controller to control the three-phase current balance on the AC side.The Proportional Integral and Repetitive Control(PI-RC)composed of PI controller and repetitive controller in series is used in MMC to suppress the positive and negative zero sequence components of double frequency in circulating current,so as to realize the constant transmission of DC power.Finally,a simulation model of the MMCHVDC system is built in MATLAB/Simulink software to verify the efficiency of the proposed optimal control strategy.

关 键 词：电流控制 不对称故障 柔性直流输电 基于双二阶广义积分器锁相环 嵌入式重 

分 类 号：TM46[电气工程—电器]