电网故障时基于MMC-PET接口风力发电系统的建模与控制  

Modeling and control of wind power generation system based on MMC-PET interface during grid faults

作　　者：程启明 孙英豪 程尹曼 张磊 渠博岗 CHENG Qiming;SUN Yinghao;CHENG Yinman;ZHANG Lei;QU Bogang(School of Automation Engineering,Shanghai University of Electric Power(Shanghai Key Laboratory of Power Plant Automation Technology),Shanghai 200090,China;North Power Supply Branch,State Grid Shanghai Electric Power Company,Shanghai 200041,China)

机构地区：[1]上海电力大学自动化工程学院(上海市电站自动化技术重点实验室),上海200090 [2]国网上海市电力公司市北供电公司,上海200041

出　　处：《电力工程技术》2024年第6期64-77,共14页Electric Power Engineering Technology

基　　金：国家自然科学基金资助项目(62303301)。

摘　　要：近年来,电力电子变压器(power electronic transformer,PET)作为电网接口的风能转换系统,无需额外的无功补偿器便可有效地抑制由风能暂态特性引起的电压波动,引起了广泛关注。但采用传统的PET结构在电网发生故障时难以控制,当电网处于不平衡时会使得控制难度进一步增加,且难以保证系统的动态性能。因此,为提升系统动态性能,增强系统的故障穿越能力,文中提出一种基于模块化多电平换流器(modular multilevel converter,MMC)型PET的新型风能转换系统的结构与控制策略。首先,文中根据系统故障时的工作状态设计基于无源滑模控制的故障切换控制策略,采用具有斩波保护功能的子模块以及时疏解故障功率;其次,利用软件仿真和半实物仿真实验平台选取典型工况对系统进行详细的模拟研究;最后,将应用文中控制策略的新型风力发电系统与传统的风力发电系统进行对比实验,实验验证了采用文中控制策略的新型系统结构具有无功功率补偿、有效限制故障时子模块电压升高和改善电能质量等优点,且满足故障条件下电网运行的最新要求,具有优秀的故障穿越能力。In recent years,the power electronic transformer(PET)used as the wind energy conversion system at the grid interface has attracted widespread attention for its ability to effectively suppress voltage fluctuations caused by the transient characteristics of wind energy without the need for additional reactive compensation devices.However,the conventional PET structure poses control challenges during grid faults,making it difficult to manage unbalanced grid conditions and compromising system dynamic performance.To enhance dynamic performance and fault tolerance,this paper proposes a novel wind energy conversion system based on the modular multilevel converter(MMC)power electronic transformer,along with its structural design and control strategy.Firstly,a fault-switching control strategy based on passive sliding mode control is designed to handle system operation during faults,incorporating sub-modules with fault protection features to dissipate fault power.Secondly,extensive simulation studies are conducted under various operating conditions using software simulation and semi-physical simulation platforms.Finally,comparative experiments between the proposed wind power generation system and traditional wind power systems validate the advantages of the novel system structure using the proposed control strategy,including reactive power compensation,effective limitation of submodule voltage rise during faults,and improvement in power quality.The results demonstrate the outstanding fault crossing capabilities of the proposed system in meeting the latest requirements for grid operation under fault conditions.

关 键 词：模块化多电平换流器(MMC) 电力电子变压器(PET) 风电并网接口 风力发电系统 无源滑模控制 故障穿越 

分 类 号：TM46[电气工程—电器]