Ensuring Resilient Operation of the Future Power System with High Levels of Renewables using Switched Mode Devices

近年来，电力系统已经看到了新类型的发电和负载的快速引入。这些新组件中的许多通过由嵌入式数字信号处理器控制的电力电子转换器连接到电网。这种转换器与传统电网中占主导地位的机电机器和无源设备具有非常不同的行为。电力电子接口装置由于调节时间快和数字信号处理器编程灵活，具有更强的整体可控性。根据程序设置，它们可以在各种不同的动态模式下运行。此外，各种新的复杂的混合动力学已经出现在电网中，其机制知之甚少。该提案旨在分析这些新的动态，并提供工程设计准则，可以提供系统范围的性能guarantee.Due的电力电子转换器接口的可再生资源和负载与更传统的设备在电网中互连的快速增加，新的复杂的混合动力学已经出现。在这个项目中，一个集合理论的框架，并提出了一个特征集的概念来解释开关行为，标签离散事件和现代电力系统的综合模式。在此原则下，一个基于被动性的屏障证书框架被制定为一个数学程序来计算相应的模式的特征集，这样就可以建立监督级合成。此外，利用变换器的可控性，控制李雅普诺夫障碍函数设计的补充控制，以减少传统的反馈控制器的保守性，扩大功能集，并提供系统范围内的性能保证。模态综合和控制的目标是保证状态在安全范围内运行，即，在操作限制内。主要研究工作包括：（a）建立适当的数学基础，以估计具有期望性能的安全域，即误差估计和算法收敛性;（B）设计满足系统要求的保性能反馈控制器;（c）将设计的控制器与现有的具有非线性的控制器进行集成（主要是死区和饱和），形成综合的混合闭环系统设计;（d）在集中式、分散式或分布式结构下，为连通网络综合不同源之间的多种模式;以及（e）通过在无限维连续空间和模型简化的有限和离散近似的框架中所需的正性证书的替代程序实现来解决可缩放性问题。

In recent years, electric power systems have seen a rapid introduction of both new types of generation and loads. Many of these new components interface to the grid through power electronic converters that are controlled by embedded digital signal processors. Such converters have a very different behavior than the electromechanical machines and passive devices that have been predominant in the traditional grid. Power electronic interfaced devices have greater overall controllability because of their fast regulating time and the flexible programming of digital signal processors. Depending on the program settings, they can operate under a variety of different dynamic modes. Moreover, a variety of new complex hybrid dynamics have arisen in the power grid whose mechanisms are poorly understood. This proposal seeks to analyze these new dynamics and provide engineering design guidelines that can provide system-wide performance guarantees.Due to a rapid increase of power electronic converters interfaced renewable resources and loads interconnected with the more traditional devices in the power grid, new complex hybrid dynamics have arisen. In this project, a set-theoretic framework is introduced and a feature set concept is proposed to explain switching behavior, label discrete events and synthesize modes for modern power systems. Under this principle, a passivity-based barrier certificate framework is formulated as a mathematical program to compute the feature sets of corresponding modes such that the supervisory level synthesis can be established. Moreover by taking advantage of converter controllability, a control Lyapunov-barrier function is employed to design a supplementary control to reduce the conservatism of traditional feedback controllers, enlarge the feature sets and provide system-wide performance guarantees. The mode synthesis and control objective is to ensure states operate within a safe range, i.e., within operational constraints. The main research tasks include: (a) establishing the proper mathematical foundation to estimate safe regions with desired properties, namely, estimate the errors and algorithm convergence; (b) design property-preserving feedback controllers to meet system requirements; (c) integrate designed controllers and existing controllers with nonlinearities (primarily, deadband and saturation) to form a comprehensive hybrid closed-loop system design; (d) synthesize multiple modes among different sources under a centralized, decentralized or distributed structure for a connected network; and (e) address scalability issues through alternative program realization of positivity certificates required in the framework of finite and discrete approximations of infinite dimensional continuous space and model reductions.