交直流配电网主动型电能路由器作用机理及故障穿越综合策略研究

In recent years, based on the national strategy of renewable energy generation and environment protection, the development trend of hybrid AC and DC distribution grids characterized by efficient energy interconnection and power electronics domination have been formed in order to enhance the penetrance of distributed energy generation and the reliability of distribution grid operation. Under this background, this project explores an active power router, as a key technology used in AC and DC distribution grids, for solving the complex fault ride-through issues. To overcome the shortcomings of passive locking of present power router, this project develops a new idea of active control for fault voltage correction and short circuit current restriction, and studies the topology, mechanism and control strategy of the active power router. According to analyzing the fault characteristics and responses of AC and DC distribution grids, the topology of active power router with fault ride-through capability and its multi-port coordination control method are raised. Then, the fault ride-through control methods of active power router under faults in AC and DC distribution grids are proposed. The dynamic physical experiments will be made to verify the proposed technologies. This project is going to enhance the fault ride-through ability of AC and DC distribution system by use of new power router based on the active control and fault isolation technology. Therefore, this project will contribute to promoting the process of engineering application for active power router, and achieving the objectives of flexible access of distributed generation and complex load, and the safe operation of distribution grids.

遵循新能源发电和环境保护国家战略，为提升分布式能源发电的渗透率和配电网运行的可靠性，近年来已形成以高效能源互联和电力电子化为特征的新型交直流区域配电网/微电网发展趋势。本项目以此为背景，针对解决复杂故障穿越关键问题，探索一种作为交直流配电网核心的主动型电能路由器技术。为克服以往电能路由器被动闭锁隔离故障的不足，本项目采用故障电压校正和短路电流限制的主动控制思路，研究主动型电能路由器拓扑结构、作用机理及控制策略。通过交直流配电网故障特征与响应分析，提出主动型电能路由器具有故障穿越能力的拓扑结构和多端口协调控制方法，提出交流故障和直流故障下主动型电能路由器故障穿越运行控制方法，并进行动模实验验证。本研究将在发挥电能路由器隔离交直流故障优势的同时，通过主动控制增强配电系统故障穿越能力，推进主动型电能路由器技术工程化进程，达到多种分布式能源、复杂负荷灵活接入和配电网安全运行的目标。

分布式新能源广泛接入的配电网是新型电力系统建设的关键技术之一，本项目立足于基于电能路由器保障配电网安全高效持续供电新模式的发展和需求，聚焦于交直流配电网主动型电能路由器基础技术及其安全运行难题，突破交直流断路器被动隔离故障或电能路由器被动闭锁的常规思路，提出了作为区域配电网系统级供电设备的主动型电能路由器及其应对各种故障的工作原理和应对策略。本项目主要研究成果包括：.（1）提出了一种适用于交直流电网互联的MMC型电能路由器拓扑结构，提出采用具备负电平输出能力的MMC型高压级、真双极MMC型变压隔离级，为其功能实现与交直流故障穿越提供基础。.（2）提出了基于四层电容电压均衡和桥臂电流控制的电能路由器高压级MMC故障穿越综合控制策略，实现了在高压交/直流电网故障、交流电压畸变、电能质量治理等复杂工况下的高压级统一控制。.（3）提出了一种基于PWM+移相的电能路由器变压隔离级BiMMDC子模块电容电压综合控制策略及其单极故障穿越控制策略，实现了双向功率传输时子模块电容电压平衡及故障穿越功能。.（4）提出了一种基于分数阶谐波干扰观测器的电能路由器低压级LCL型变流器电流内环控制策略，提高了变流器在稳态和动态过程的输出电流质量。.（5）提出了一种基于串联虚拟电阻的电能路由器级间稳定控制方法，结合低压直流端口电流前馈控制，提升系统稳定性的同时加快了动态响应速度。.（6）搭建了数字仿真平台、物理模拟实验平台进行主动型电能路由器实验室模拟，验证了所提拓扑与故障穿越控制策略的正确性和有效性。.在该项目支持下，项目组按计划完成了全部研究内容，较好实现了项目既定研究目标。共资助发表了SCI/EI论文25篇，其中SCI论文11篇，EI论文14篇；授权发明专利10项；获国际会议优秀论文奖1项；培养了博士生5名，硕士生7名；获湖北省科技进步奖一等奖1项（排名2）。本课题取得的重要成果已与相关单位开展合作，将推动研究成果的工程化应用，为电能路由器的发展提供技术支持。