Multi-terminal dc transmission micro-grid system for interfacing multiple wind turbines

减少碳排放和提高效率的举措引发了人们对发电新技术的兴趣。与传统发电厂不同，新的发电技术自然不适合直接连接到固定频率的电网供电。此外，在可再生发电的情况下，地理位置的限制给电力连接带来了问题。因此，电力电子变换在有效地捕获和分配所产生的能量方面起着重要作用。这项建议涉及这一研究领域的一个重要方面：从多种可再生资源中高效、稳健和低成本地捕获和传输可再生能源。利用直流网络汇聚和传输电力已被确定为解决这些问题的一种方法；到目前为止，这一领域的工作主要集中在概念研究和模拟层面。我们的合作提案旨在开发一种新颖和创新的直流电流链系统。这项研究将调查实现直流电流链技术以捕获可再生能源和其他形式的低碳衍生电能的学术研究方面。传统的风电机组接入交流电网是基于交流概念的。最近，ABB安装了第一个基于直流输电的海上互联。该系统使用他们的标准轻型高压直流输电技术，提供双向功率流控制。嵌入式可再生发电，无论是风能还是海浪，无论是陆上还是海上，通常不需要轻型高压直流输电(以及类似技术)的双向电力流动能力，但需要高效、低成本的多电源控制。现有的技术，如轻型高压直流输电，并不适用。该系统不同于现有的直流输电技术。拟议的系统基于这样的概念，即并联能源应始终基于并联电流源，而不是目前以高压直流系统为例的电压源。在我们所提出的系统中，单端升压变流器与外部电流控制环路一起工作，是基本的构成模块。与现有的配电用交直流变流器技术相比，该拓扑结构具有可扩展性、可靠性和低成本等特点。更多来源的连接是简单和低成本的，因此该系统适合于社区计划。此外，大多数较低功率的稀土系统使用永磁发电机，因此只需要从稀土源到电网的单向电力流动。功率流的单向性质导致了直流系统的显著简化，这在交流系统和现有的双向直流技术中是没有实现的。该项目将开发的技术是整合多源低碳能源的关键推动因素。学术研究团队将对演示直流连接系统进行详细的建模、仿真、设计和实验。已经确定了两个博士主题。第一个项目将由一名博士生研究缓冲发电所需的转换电子学，并将产生的电能转换到新的网络上。第二个博士生将研究和解决从低碳能源到中央电网接口转换器的电力流动调节这一重要问题。一名博士后研究员将提供全面的项目管理，在开发六涡轮示范场地期间与行业合作伙伴联络，并评估和评估示范的表现。该项目完成后，将有六个15kW的涡轮机阵列，展示通过这项重要研究开发的新型转换技术和创新的控制算法。该示范者将是国际领先的学术研究、工业经验和开发以及创业技能相结合的典范。

Moves to reduce carbon emissions and improve efficiency has primed interest in new technologies for the generation of electrical power. Unlike conventional plant, new generating technologies are not naturally suited to direct connection to the fixed frequency grid supply. Furthermore, in the case of renewable generation, restrictions on geographical location pose problems for electrical connection. Power electronic conversion thus plays a significant role in efficiently capturing and distributing the generated energy. This proposal addresses one important aspect of this research area: the efficient, robust and low-cost capture and transmission of renewable energy (RE) from multiple renewable resources. The use of DC networks to aggregate and transmit power from has been identified as a solution to such problems; to date work in this area has be concentrated at concept study and simulation level. Our collaborative proposal seeks to develop a novel and innovative DC current link system. The research will investigate the academic research aspects of realising a DC current link technology for the capture of renewable energy and other forms of low-carbon-derived electrical energy. Traditional wind turbine interfacing to the AC grid has been based on AC concepts. Recently ABB have installed the first offshore interconnect based on dc transmission. The system uses their standard HVDC Light technology, which offers bidirectional power flow control. Embedded renewable generation whether wind or wave, onshore or offshore, generally does not require the bidirectional power flow capability of HVDC Light (and similar techniques) but does require efficient, low-cost multi-source control. Existing techniques, e.g.HVDC Light, are not suitable. The proposed system departs from existing DC transmission technology. The proposed system is based on the concept that paralleling energy sources should always be based on paralleling current sources - not voltage sources as currently exemplified by HVDC systems. In our proposed system the single-ended step-up converter, operated with an outer current control loop, is the basic building block. The topology is scaleable, reliable and low-cost compared with existing AC and DC converter technologies used in distribution. Connection of additional sources is simple and low-cost thus the system lends itself to community-based schemes. Additionally, the majority of lower power RE systems utilise permanent magnet generators therefore require only unidirectional power flow from the RE source to the grid. The unidirectional nature of the power flow results in significant simplification of the DC system that is not realised in AC systems and existing bidirectional DC technology. The technology that will be developed by this project is a key enabler for the integration of multi-source low-carbon energy. The academic research team will investigate detailed modelling, simulation, design and experimentation on a demonstrator DC link system. Two PhD themes have been identified. The first will have a PhD student investigating the conversion electronics required to buffer and transform generates electrical energy onto the novel network. The second PhD student will research and address the important issue of regulating the flow of power from the low carbon energy source to the centralised grid interfacing converter. A post-doctoral research fellow will provide overall project management, liaise with the industry partner during development of the six-turbine demonstrator site, and assess and evaluate the performance of the demonstrator. On completion of this project, there will be a six 15kW turbine array that demonstrates the novel conversion technologies and innovative control algorithms developed through this important research. The demonstrator will be an exemplar of the synthesis between internationally-leading academic research, industrial experience and exploitation, and entrepreneurial skill.