多约束下光储系统的灵活惯性控制及自律协同稳定运行研究

When the photovoltaic and energy storage generator is controlled by the virtual synchronous generator (VSG) control, its virtual inertia can be controlled flexibly, and it can be named as flexible inertia system. The inertia of the virtual inertial system can be controlled flexibly in a certain range, which makes the optimization and improvement of the controller possible. The coordination among multi-flexible inertia systems becomes a problem to be solved after the virtual inertia systems connected to the grid. This project plans to firstly analyze the substantive characteristics and multiple constrained coupling mechanism of the flexible virtual inertia system, and build its stable operation boundary system. On this foundation, superiority of the virtual inertia derived from its flexible controllability in a certain range is to be fully excavated. The adaptive control method of the flexible inertia system under multi-constraint conditions and its influence on the system frequency, damping and stability margin will be researched. Finally, in order to make the photovoltaic and energy storage flexible inertial systems work autonomously inside and operate synergetically with each other, a comprehensive frequency control method is going to be proposed. With the proposed method, excellent interaction and coordinated operation among multiple inertial systems can be achieved and the problem of power system frequency stability with multiple virtual inertial systems will be solved. A hardware-in-the-loop simulation system and a physical dynamic experiment platform for the grid comprised of photovoltaic generation, energy storage systems and synchronous generators will be built to verify and evaluate the proposed control method.

光储发电单元采用虚拟同步发电机控制时，其虚拟惯量具有灵活可调的特性，可称之为灵活惯性系统。虚拟惯量一定范围内的灵活可调为其控制器的优化改进提供了可能，此基础上的多灵活惯性单元协同稳定运行技术是目前亟待解决的问题。本课题首先分析灵活可控惯性系统本质特征及多约束耦合机理，构建其稳定运行边界性能指标体系。在此基础上，充分挖掘虚拟惯量可在一定范围内灵活调整的优势，研究多约束条件下灵活惯性系统自适应控制方法，揭示其对电网系统频率、阻尼和稳定裕度的影响机理。最后，提出光储灵活惯性系统内部自律、相互之间协同优化运行的频率控制方法，实现多灵活惯性系统之间的良好互动与协调运行，解决含多灵活虚拟惯性系统的电网频率稳定性问题。本课题将搭建由光伏、储能及同步发电机组等组成的新能源高渗透率电网下的硬件在环仿真和物理动态模拟实验平台，对所提出的控制策略进行验证与评估。

光储系统的虚拟惯性控制有助于提高光伏电源的渗透率和利用率，其虚拟惯性大小可控是一重要特征与优势，但实际应用时的约束条件及未来大量此类灵活虚拟惯性系统的接入将对光储系统的惯性控制提出更高的要求。本项目重点研究了通过多约束下单个光储单元的灵活惯性控制及多单元的自律协同运行方法，有效利用光储系统中存储的能量对电网系统提供灵活可控的惯性支持，以提高含高渗透率间歇性电源的交流电网的频率质量和稳定性。本项目主要的研究内容是：.（1）建立了含虚拟惯性单元的电网系统模型，研究了虚拟惯性形成机理及灵活可控特性，分析了灵活可控惯性系统的多约束耦合机理，构建了灵活可控惯性系统多约束下稳定运行的性能指标体系；.（2）提出了自适应系统频率变化的灵活惯性控制方法，分析了自适应灵活惯性对系统动态频率特性的影响机理，揭示了所提方法对系统稳定性的影响规律；.（3）研究了单个基于灵活惯性控制的光储系统自律运行方法，提出了多个含灵活惯性控制的光储系统分级协同运行方法，对控制参数的整定原则及优化方法进行了研究；.（4）搭建了不同时间尺度下硬件在环仿真和物理动态模拟实验平台，对理论分析及所提方法进行了验证。.在本项目中，提出了一种多约束限制下的灵活虚拟惯性控制方法，该方法兼顾储能单元的极限工作状态、系统频率变化率、换流器容量以及系统单位时间功率可调量的影响，具有首创性。此外，在多个VSG单元协同运行方面，提出了一种基于逼近于理想值排序方法的多VSG单元协同控制策略，实现了多VSG单元在提供惯性支撑时的协同配合。.通过本项目的实施，有效提升了光储单元虚拟同步发电机控制方法的实用性，对光储新能源接入的友好性及构建以新能源为主体的新型电力系统具有重要的意义。