Single-phase PV-battery synchronverter with seamless transition to stand-alone mode

日益增长的气候担忧和能源需求推动了可再生能源系统的发展，主要是风力涡轮机和光伏电池板。电力电子转换器用于将这些能源连接到电网。在英国等现代电力系统中，这些基于变流器的能源的份额不断增加，这带来了一些重大挑战。与传统的同步发电机相比，这些变流器没有惯性或阻尼。这导致电力系统的动态和暂态性能恶化，不稳定和停电的风险增加。同步器或虚拟同步机(VSM)的概念已经被提出，以将基于电力电子的能源整合到现有电网中，使其与现有的同步发电机兼容。虽然各种技术已被提出并以不同的方式呈现，但它们都旨在提供虚拟阻尼、虚拟惯性以及调速器和自动电压调节器(AVR)功能。现有的解决方案主要集中在三相变流器上，而国内单相光伏系统的日益普及要求研究类似的想法，并为单相变流器寻找可能的机会。另一方面，许多家用光伏系统主要使用电池存储，这为任何可能的组合解决方案提供了更大的灵活性和复杂性。该项目的目的是提出一种电力电子拓扑和控制技术的组合，使国内单相光伏电池系统能够模拟同步发电机的动态特性，并在公用电网的电压和频率瞬变期间提供辅助服务。此外，它应该能够在可能发生电网断开的情况下提供负载。该系统将充分研究不同参数下的性能，并将根据不同的电网编码要求和运营商的偏好，提出一种简单的设计和参数选择算法，以充分利用所提出的同步器。理论结果将通过在MatLab/Simulink中的大量仿真得到验证。

Increasing climate concerns and energy demands have prompted the development of renewable energy systems, mainly wind turbines and photovoltaic (PV) panels. Power electronic converters are used to connect these energy sources to the electrical grid. Increasing the share of these converter-based energy sources in modern electrical power systems, such as the UK, has created some major challenges. Comparatively to conventional synchronous generators, these converters present no inertia or damping. This results in deteriorated dynamic and transient power system performance and a higher risk of instability, and blackouts.The synchronverter or virtual synchronous machine (VSM) concept is already proposed to integrate power electronic-based energy resources into an existing grid so that they are compatible with the existing synchronous generators. Although various techniques have been proposed and presented in different ways, they all aim at providing virtual damping, virtual inertia, and the governor and automatic voltage regulator (AVR) functions. Existing solutions are mainly focused on three-phase converters, while the ever-increasing penetration of single-phase domestic PV systems is calling for similar ideas to be investigated and possible opportunities to be discovered for the single-phase converters. On the other hand, many residential PV systems are dominantly using battery storage, which provides more flexibility as well as complexity for any possible combined solution. The aim of this project is to propose a combination of power electronic topologies and control techniques that will enable domestic single-phase PV-battery systems to mimic the dynamics of synchronous generators and to provide ancillary services during voltage and frequency transients of the utility grid. Additionally, it should be capable of supplying loads in the event of a possible grid disconnection. The performance of the proposed system to different parameters will be fully investigated and a straightforward design and parameter selection algorithm will also be proposed to make the most out of the proposed synchronverter according to different grid code requirements and operator preferences. The theoretical results will be verified through extensive simulations in Matlab/Simulink.