大信号扰动下多并网虚拟同步发电机系统动态特性与协调控制研究

The multiple on-grid virtual synchronous generator system has oscillation and is easily escaped from attraction domain and could not return to equilibrium point after it is in the large signal perturbation. In order to solve this difficult problem, a thinking of “local autonomy and global coordination” will be offered to obtain the stability of multiple synchronous generator system in the large signal perturbation, which will be guided by motion model theory and implemented by utility of limited network resources. Some significant research contents are planned to investigate as follow. ① The mechanism analysis based on power-angle motion model with the time-scale of current control will be explored, as well as the design methods of coefficients, which realizes both dynamic characteristics and stability margin optimized for global synchronized stability services. ② According to Norton's equivalent circuit and the proposed concept of coupling power, the stability problems of multiple on-grid virtual synchronous generator system in the large signal perturbation, will be transformed into the synchronized problems of power-angle dynamic motion based on Kuramoto’s model, which benefits to generate the theoretical criterion and constraint conditions for global cooperative control. ③ To achieve the global stability, the matching relation between coupling power among virtual synchronous generators and allocation of network resources will be revealed. The cooperative strategies based on networked control will also be optimized. One of the major contributions of this project is to provide a solid theoretical basis for the study on anti-interference dynamic and stability performance of the on-grid virtual synchronous generator system. Moreover, some core intellectual properties can be issued to expand the technology of virtual synchronous generator in our country.

针对多并网虚拟同步发电机系统经受大信号扰动后振荡和易脱离吸引域无法回到平衡点的难题，以运动模型理论为指导，有限通讯资源使用为手段，提出“局域自治全局协调”的思路来获取大信号扰动下多机系统的稳定实现，本项目重点研究如下内容：①探索考虑电流控制时间尺度基于功角运动模型的机理分析及参数设计方法，实现VSG单机动态性能与稳定裕度优化，为全局稳定服务。②根据诺顿等效电路及提出的耦合功率概念，将多机系统大信号扰动的稳定问题转化为基于Kuramoto模型的功角动力学同步问题，为全局协调控制提供理论判据和约束条件。③揭示保持同步稳定虚拟同步发电机耦合功率与通信资源布局的匹配关系，优化基于网络控制的协调策略，实现多机全局稳定。本项目的开展，将为并网虚拟同步发电机系统的抗干扰动态与稳定性研究提供坚实的理论基础。同时，相关研究成果将形成具有自主知识产权的发明专利，扩大虚拟同步发电机技术在我国的推广。

针对多并网虚拟同步发电机系统经受大信号扰动后振荡和易脱离平衡点而失稳的难题，以运动模型理论为指导，暂态控制策略为手段，提出“局域自治全局协调”的思路来获取大信号扰动下多机系统的稳定实现，本项目主要研究内容如下：①探索考虑内环控制时间尺度基于功角运动模型的机理分析及参数设计，实现基于内电势理论的动态特性分析方法，讨论了不同静态工作点及电网强弱下的虚拟同步机并网暂态稳定性，提出不改变有功和无功惯量特性的辅助校正暂态控制策略；②分析虚拟同步机在三相短路及电网电压跌落故障下的暂态特性，揭示大信号扰动下的失稳机理，提出基于虚拟阻抗的抑制三相短路故障并网参数设计方法，以及基于无功功率环暂态反馈的抑制电网电压跌落控制策略；③提出基于混合势函数法、基于耦合功率的二阶Kuramoto功角模型、基于扩展等面积法则（EEAC）从多角度解析多并网虚拟同步机系统不同大信号扰动下的暂态稳定性，建立大信号扰动下多虚拟同步机系统的数学模型，为全局协调控制提供理论判据和约束条件；④从基于网络控制与分布式控制两类方法探索大信号扰动下多虚拟同步机暂态协调控制方法，结合仿真与实验手段验证方法的有效性，实现多机全局稳定。本项目为并网虚拟同步发电机系统的抗干扰暂态稳定性研究提供坚实的理论基础。同时，相关研究将形成具有自主知识产权成果，扩大虚拟同步发电机技术在我国新能源、智能电网及大规模储能等领域的推广。