Distributed High Power Density Converters for Renewable Energy Resources with Optional Energy Storage Systems

由于中央发电厂对环境的负面影响和效率低下，可再生分布式发电(DG)系统在电网系统中激增。可再生能源可能包括太阳能、燃料电池、风能或其他可再生能源。可再生DG的设计者和用户面临的一个主要问题是这些能源资源的随机、波动性质。由于这类系统是间歇性的，容易出现稳定性问题，因此使用存储变得至关重要，将存储集成到DG系统已成为主流。税收优惠措施，如各州的《存储2013法案》、德国对能源存储系统的补贴、美国军队最近的投资，以及由欧洲和加拿大的几个合作伙伴组成的财团最近推出的项目，都是证明能源存储系统重要性的几个例子。因此，设计和实施包括储能选项的新型电力电子系统(PES)在未来几十年将是至关重要的。**PES旨在从可再生DG中提取电力，并将其提供给负荷和电网。然而，现有的大多数PESS只有在存在带电电网的情况下才能运行，即所谓的并网运行模式。这类系统通常不支持在停电时向负载供电，这种停电模式称为孤岛运行模式。支持这两种操作模式的PES通常需要储能设备，并且通常是定制设计的，复杂得多。对于光伏(PV)系统，支持这两种模式的现有PES主要设计在“中央”配置中，其中所有PES接口和控制系统都设计在一个设备中。然而，中央PESS表现出严重的缺点，如在部分遮荫条件下能量收集不佳。因此，最近的研究集中在“分布式”PESS的发展上，如微型逆变器和模块集成转换器。在分布式PESS中，每个模块或单元都有一个指定的PES，以最大限度地收集能量。由于许多理论和实践上的挑战，目前还没有针对孤岛运行模式的分布式PESS进行研究和设计。开发一种新的分布式PES配置，具有可选的能量存储，最大限度地提高效率并最大限度地降低生产和安装成本，是本提案的总体愿景。新的体系结构兼具了集中式和传统分布式PESS的优点，并增加了简单、廉价的可扩展性、支持两种操作模式和耐用性等特点。**拟议的研究有可能带来为每个用户提供许多好处的技术，无论是偏远地区的弱电网系统还是不可靠的电网系统，以及在关键负荷或没有关键负荷的情况下并网。研究的独特之处在于制度的逐步扩展与需要和负担能力成正比。这特别有利于贫穷国家或预算有限的人。与现有的可再生DG系统不同，该技术在大规模住宅应用中的使用不仅将可再生PESS用作不间断电源，而且有助于智能电网概念的发展。这是通过频率调节、高峰时间需求响应、无功补偿以及谐波和凹陷/隆起补偿来帮助平衡电网来实现的。此外，这项技术还可用于偏远社区、公用事业连接时间有限的郊区、设备站、任何移动单位，如特殊用途车辆或军事单位、电信和紧急避难所。

Due to negative environmental impacts and inefficiency of central power plants, renewable distributed generation (DG) systems have proliferated in electrical grid systems. Renewable DGs may include solar, fuel cells, wind, or other renewable energy sources. A major issue confronting designers and users of renewable DGs is the random, fluctuating nature of these energy resources. As such systems are intermittent and prone to stability issues, the use of storage has become crucial and the integration of storage into DG systems has become the mainstream. Tax incentives such as "Storage 2013 Act" in the states, subsidies on energy storage systems in Germany, recent investments by U.S. army, and launching of recent projects by consortium of several partners in Europe and Canada are a few examples that attest to the importance of energy storage systems. Therefore, design and implementation of new power electronic systems (PES) that include energy storage option will be vital in the coming decades.**PESs are designed to extract power from renewable DGs and provide it to loads and electrical grids. However, most of the existing PESs operate only when the live grid exist, known as grid connected mode of operation. Such systems normally do not support supplying power to loads when there is a power outage, known as islanded mode of operation. PESs, supporting both modes of operations, typically require energy storage devices, and are usually custom designed with much more complexity. For photovoltaic (PV) systems, existing PESs that support both modes are mainly designed in "central" configurations where all the PES interface and control systems are designed in one device. Central PESs, however, have exhibited serious shortcomings such as poor energy harvesting in partial shading conditions. Consequently, recent research is focused on the development of "distributed" PESs such as microinverters and module integrated converters. In distributed PESs, each module or cell has a designated PES to maximize energy harvesting. Distributed PESs, due to many theoretical and practical challenges, have not yet been studied and designed for islanded mode of operation. Developing a new distributed PES configuration, with optional energy storage that maximize efficiency and minimize production and installation costs is the general vision of this proposal. The new architecture has both advantages of central and traditional distributed PESs, and adds features such as simplicity, inexpensive scalability, support of both modes of operation, and durability.**The proposed research has the potential to lead to technologies that offer many benefits to every users, with weak or unreliable grid systems, in remote areas, and grid-connected with or without critical loads. The unique character of the research features gradual expansion of the system proportional to the need and affordability. This is specifically beneficial to poor countries or people with limited budgets. Unlike existing renewable DG systems, the use of this technology in large scale residential applications not only exploits the renewable PESs as an uninterruptable power supply, but also contributes to the development of smart grid concept. This is achieved by helping balance the grid through frequency regulation, peak time demand response, reactive power compensation, and harmonic and sag/swell compensation. Furthermore, this technology can be employed by remote communities, suburban areas with limited utility connection time, equipment stations, any mobile units such as special purpose vehicles or military units, telecommunications, and emergency shelters.