Analysis of Practical Microgrid Stability in the Presence of Random Events

随机事件下的实际微网稳定性分析微网是一种总发电容量与总需求相近的小型配电系统。 例子可以在孤立的村庄，军事基地，可能会或可能不会连接到周围的电网，以及车辆，从汽车到卫星到船舶。 DC微电网也被提议用于住宅应用，其中单个房屋将是一个完整的系统，以及用于电信电力系统。 微电网是广泛部署太阳能和风能系统等可再生能源的一项有利技术。 该项目将新兴的控制理论概念应用于微电网稳定性分析。 以前的研究人员通常假设所有的负载和电源都有一定的控制能力，但在实际系统中，大多数负载都是随机变化的，可再生资源也会受到天气变化的影响。 随机事件可能导致微电网变得不稳定并关闭。 由于可再生能源发电的分布式特性，微电网对可再生能源的扩展至关重要，因此需要从本项目中改进稳定性分析，以使系统运营商对其正常运行充满信心。本项目的目标是使用适用于一般脉冲马尔可夫跳变线性系统的先进技术分析交流和直流微电网。 马尔可夫跳变线性系统（Markov jump linear system，MJLS）是一个根据马尔可夫过程在一组线性动态系统之间瞬时跳变的系统。 更一般地说，离散状态中的跃迁可能伴随着连续时间状态中的脉冲，形成脉冲MJLS。 这是对微电网小信号特性的一个很好的描述。 不幸的是，一般的稳定性结果的脉冲MJLS很少。 在这个项目中，稳定性结果的子集脉冲MJLS，适当地描述微电网将被导出。 适用于交流和直流微电网的模型将被推导和分析。 结果将由控制器增益和系统设计者权限内的其他特性参数化，从而可以通过设计来保证稳定性。 同时考虑随机演化的离散状态和确定性的连续状态。 该方法将通过仿真和实验进行验证。 两个例子微电网，一个交流和一个直流，将被研究，以证明有能力组成一个适当的非线性模型，将其转换为一组小信号模型，并将其映射到脉冲MJLS框架。 所提出的脉冲MJLS研究将适用于其他动力系统，如网络控制系统，适合类似的框架。 类似地，演示脉冲MJLS方法在微电网中的应用可能会刺激电力界对适合类似结构的其他应用（例如电压调节器模块（VRM）上的负载）的研究。

Analysis of Practical Microgrid Stability in the Presence of Random EventsMicrogrids are power distribution systems that are small where total generation capacity is similar to the total demand. Examples may be found in isolated villages, military bases that may or may not be connected to the surrounding power grid, and vehicles ranging from automobiles to satellites to ships. DC microgrids have also been proposed for residential applications, where a single house would be a complete system, and for telecommunications power systems. Microgrids are an enabling technology for widespread deployment of renewable energy, such as solar and wind systems. This project will apply emerging control theory concepts to microgrid stability analysis. Previous researchers have usually assumed that all loads and sources have some ability to be controlled, but in practical systems, most loads change randomly, and renewable resources are subject to weather variations. The random events could cause the microgrid to become unstable and shut down. Microgrids are essential to the expansion of renewable energy due to the distributed nature of renewable energy generation, and the improved stability analysis from this project is needed to give system operators confidence in their proper operation.The objective of this project is to analyze ac and dc microgrids using advanced techniques that apply to generic impulsive Markov jump linear systems. A Markov jump linear system (MJLS) is a system that jumps instantaneously among a set of linear dynamical systems according to a Markov process. More generically, the transitions in the discrete state could be accompanied by impulses in the continuous-time states, forming an impulsive MJLS. This is a good description for the small-signal characteristics of a microgrid. Unfortunately, generic stability results for an impulsive MJLS are few. In this project, stability results for the subset of impulsive MJLS that appropriately describes microgrids will be derived. Suitable models for both ac and dc microgrids will be derived and analyzed. The results will be parameterized by controller gains and other characteristics that are within the purview of the system designer, so that stability may be guaranteed by design. Both the discrete state, which evolves randomly, and the continuous state, which is deterministic, will be considered simultaneously. The approach will be validated with simulations and experiments. Two example microgrids, one ac and one dc, will be studied to demonstrate the ability to compose an appropriate nonlinear model, to convert it to a set of small-signal models, and to map it into the impulsive MJLS framework. The proposed impulsive MJLS study will be applicable to other dynamical systems, such as networked control systems, that fit a similar framework. Similarly, demonstrating the application of impulsive MJLS methods to microgrids may stimulate research within the power community on other applications that fit a similar structure, such as the load on a voltage regulator module (VRM).