计及异构多机耦合和结构时变特征的微电网暂态同步稳定机理与控制研究

可再生能源通过逆变器接入微电网，利用锁相环或功率同步环等同步控制策略实现并网同步，其同步机制与同步发电机存在显著差别。受暂态过程中多微源、多控制回路交互耦合与逆变器控制切换特征的影响，微电网在短路故障、负荷投切等大扰动下易发生暂态同步失稳问题。针对此问题，本项目拟从建模方法、机理分析、稳定控制三个层面开展微电网的暂态同步稳定问题研究。首先，考虑宽时间尺度内的系统动态交互，构建精确描述暂态同步过程的高可信度降阶简化模型；之后，计及多类型微源耦合与控制结构时变特征，揭示微电网的暂态同步失稳成因及影响因素；同时，基于切换哈密顿系统理论得到同步稳定性判据，定量分析同步稳定裕度及其关键影响因素；最后，提出分阶段、多层级的同步稳定控制策略，协调各类型微源提升微电网的暂态同步稳定性。本项目成果将为微电网的暂态稳定运行提供理论基础，并促进电力电子化电力系统和飞机、船舶等独立供电系统的暂态问题研究。

Distributed micro-sources are connected to the micro-grid through power electronic inverters, and use synchronization control strategies such as phase-locked loops or power control loops to achieve grid-connected synchronization. The synchronization mechanism of micro-sources is significantly different from that of synchronous generators. The coupling effect between different types of micro-sources and inverter control switching can easily lead to transient synchronization instability issues under large disturbances such as short-circuit faults. This project intends to research on the analysis and control of synchronization and stability between multiple micro-sources in microgrids. First, establish a reduced-order simplified model that accurately describes the transient synchronization process. Then analyzes the transient synchronization stability considering the coupling of heterogeneous multi-machines and control switching, the mechanism of synchronization instability between micro-sources is obtained, stability criteria are obtained based on the switching Hamiltonian system theory, and the key factors affecting synchronization stability margin are revealed. Finally, the system-level synchronization control of microgrid is studied, through the construction of a multi-level control framework, various types of micro sources are coordinated to improve the transient synchronization stability of microgrids. The research of this project will improve the stable operation of microgrids under large disturbances, promote the research of distributed power generation and microgrids, and guide the application of microgrids.