757 research outputs found

    The future of electrical power grids: a direction rooted in power electronics

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    Electrical power grids are changing with a focus on ensuring energy sustainability and enhanced power quality for all sectors. Over the last few decades, there has been a change from a centralized to a decentralized paradigm, which is the consequence of a large-scale incorporation of new electrical technologies and resultant equipment. Considering the foreseeable continuation of changes in electrical power grids, a direction rooted in power electronics with a focus on hybrid AC/DC grids, including the support of solid-state transformers and unified systems, is presented in this paper. Converging on hybrid AC/DC grids, DC grids (structured as unipolar and bipolar) and coupled and decoupled AC configurations are analyzed. On the other hand, in the context of solid-state transformers, feasible structures are analyzed, including the establishment of hybrid AC/DC grids, and the assessment of gains for boosting power quality is presented. Unified power electronics systems are also of fundamental importance when contextualized within the framework of future power grids, presenting higher efficiency, lower power stages, and the possibility of multiple operations to support the main AC grid. In this paper, such subjects are discussed and contextualized within the framework of future power grids, encompassing highly important and modern structures and their associated challenges. Various situations are characterized, revealing a gradual integration of the cited technologies for future power grids, which are also known as smart grids.This work was supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

    UK energy in a global context: synthesis report

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    A unified topology for the integration of electric vehicle, renewable energy source, and active filtering for the power quality improvement of the electrical power grid: an experimental validation

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    Electrical power grids are facing challenges concerning new linked technologies and associated contributions of power electronics, both regarding innovative topologies of power converters and advanced power management algorithms. Additionally, technologies related to renewables and electric mobility have several points in common, especially about the interface with the power grid, which allows to foresee a convergence for unified solutions in the power grid interface, without jeopardizing the functionalities and added values of each technology. Encompassing this purpose, this paper presents a unified topology, based on a three-phase structure, which, in addition to a collaborative operation with the power grid targeting the compensation of power quality problems, also enables the integration of a renewable energy source and an electric vehicle. The main contribution of this paper resides in the fact that only an interface with the power grid is necessary to involve three central features of smart grids: renewables, electric mobility, and power quality. Overall, the unified topology presents a four-quadrant structure, both in the perspective of AC and DC interfaces, offering multiple functionalities, mainly to the power grid. In the AC interface, the structure operates in interleaved mode, while in the DC interface, the structure operates in multilevel mode. The global control algorithm is presented, covering the interconnection between the mentioned technologies, as well as the details of implementation of the individual control algorithms regarding each interface. A laboratory prototype, connected to a three-phase 400 V-50 Hz power grid, was used to obtain an experimental validation for a maximum operating power of 12.5 kW, corroborating the essential advantage characteristics and the correct functioning of the presented unified topology.This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEIEEE/30283/2017 and by the FCT Project DAIPESEV PTDC/EEIEEE/30382/2017

    Tackling the Challenge of Climate Change: A Near-term Actionable Mitigation Agenda

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    United Nations Secretary General Ban Ki-moon has invited world leaders to come to the Climate Summit on September 23, 2014 to deliver "bold pledges" to tackle climate change. This paper was prepared at the request of the Republic of Nauru, Chair of the Alliance of Small Island States, as part of their answer to that call. We believe the path to the global low-carbon transformation needed to tackle the climate crisis is within reach, but requires decisive political action from leaders around the world, now. This paper is unabashedly prescriptive on the need for action, but recognizes that there are multiple approaches and models from around the world that can be scaled up and adapted to national circumstances. Cost-effective technologies for a low-carbon economy are being implemented throughout the world, but at nowhere the scale and speed necessary. Emissions continue to rise. With every year of delay, human suffering, biodiversity loss, and the costs of mitigation and adaptation increase. We are running out of time

    Energy scenarios for Denmark and Europe

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    Conclusions and recommendations

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    System aspects

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    The global energy scene in 2050

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    Hydropower

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