scholarly journals The Role of Front-End AC/DC Converters in Hybrid AC/DC Smart Homes: Analysis and Experimental Validation

Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2601
Author(s):  
Vitor Monteiro ◽  
Luis F. C. Monteiro ◽  
Francesco Lo Franco ◽  
Riccardo Mandrioli ◽  
Mattia Ricco ◽  
...  

Electrical power grids are rapidly evolving into smart grids, with smart homes also making an important contribution to this. In fact, the well-known and emerging technologies of renewables, energy storage systems and electric mobility are each time more distributed throughout the power grid and included in smart homes. In such circumstances, since these technologies are natively operating in DC, it is predictable for a revolution in the electrical grid craving a convergence to DC grids. Nevertheless, traditional loads natively operating in AC will continue to be used, highlighting the importance of hybrid AC/DC grids. Considering this new paradigm, this paper has as main innovation points the proposed control algorithms regarding the role of front-end AC/DC converters in hybrid AC/DC smart homes, demonstrating their importance for providing unipolar or bipolar DC grids for interfacing native DC technologies, such as renewables and electric mobility, including concerns regarding the power quality from a smart grid point of view. Furthermore, the paper presents a clear description of the proposed control algorithms, aligned with distinct possibilities of complementary operation of front-end AC/DC converters in the perspective of smart homes framed within smart grids, e.g., enabling the control of smart homes in a coordinated way. The analysis and experimental results confirmed the suitability of the proposed innovative operation modes for hybrid AC/DC smart homes, based on two different AC/DC converters in the experimental validation.

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 118 ◽  
Author(s):  
Vitor Monteiro ◽  
Jose Afonso ◽  
Joao Ferreira ◽  
Joao Afonso

Nowadays, concerns about climate change have contributed significantly to changing the paradigm in the urban transportation sector towards vehicle electrification, where purely electric or hybrid vehicles are increasingly a new reality, supported by all major automotive brands. Nevertheless, new challenges are imposed on the current electrical power grids in terms of a synergistic, progressive, dynamic and stable integration of electric mobility. Besides the traditional unidirectional charging, more and more, the adoption of a bidirectional interconnection is expected to be a reality. In addition, whenever the vehicle is plugged-in, the on-board power electronics can also be used for other purposes, such as in the event of a power failure, regardless if the vehicle is in charging mode or not. Other new opportunities, from the electrical grid point of view, are even more relevant in the context of off-board power electronics systems, which can be enhanced with new features as, for example, compensation of power quality problems or interface with renewable energy sources. In this sense, this paper aims to present, in a comprehensive way, the new challenges and opportunities that smart grids are facing, including the new technologies in the vehicle electrification, towards a sustainable future. A theoretical analysis is also presented and supported by experimental validation based on developed laboratory prototypes.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8585
Author(s):  
Joao L. Afonso ◽  
Mohamed Tanta ◽  
José Gabriel Oliveira Pinto ◽  
Luis F. C. Monteiro ◽  
Luis Machado ◽  
...  

Nowadays, new challenges arise relating to the compensation of power quality problems, where the introduction of innovative solutions based on power electronics is of paramount importance. The evolution from conventional electrical power grids to smart grids requires the use of a large number of power electronics converters, indispensable for the integration of key technologies, such as renewable energies, electric mobility and energy storage systems, which adds importance to power quality issues. Addressing these topics, this paper presents an extensive review on power electronics technologies applied to power quality improvement, highlighting, and explaining the main phenomena associated with the occurrence of power quality problems in smart grids, their cause and effects for different activity sectors, and the main power electronics topologies for each technological solution. More specifically, the paper presents a review and classification of the main power quality problems and the respective context with the standards, a review of power quality problems related to the power production from renewables, the contextualization with solid-state transformers, electric mobility and electrical railway systems, a review of power electronics solutions to compensate the main power quality problems, as well as power electronics solutions to guarantee high levels of power quality. Relevant experimental results and exemplificative developed power electronics prototypes are also presented throughout the paper.


2018 ◽  
Vol 2 (1) ◽  
pp. 52-63
Author(s):  
Ansori Ansori

The use of various methods will greatly help students in achieving learning goals. As role play method is one way mastery of learning materials through the development of imagination and appreciation of students on learning materials. Data collection techniques in this study are observation, interviews, and documentation. To analyze the data in this research using data analysis technique of Miles and Huberman model that is data reduction (Data Reduction), data presentation (Data Display) and conclusion (Conclution Drawing / verification) The findings in this research is innovation of role play method can change paradigm to the new paradigm so that the role of the teacher is more as a facilitator, counselor, consultant, and comrade study Flexible schedule, open as needed Learning directed by students themselves Problem-based, project, real world, real action, and reflection Design and investigation. Computers as tools, and dynamic media presentations.


2020 ◽  
pp. 875697282097722
Author(s):  
Denise Chenger ◽  
Jaana Woiceshyn

The front end of projects is strategically important; yet, how project concepts are identified, evaluated, and selected at the pre-project stage is poorly understood. This article reports on an inductive multiple-case study of how executives made such decisions in major upstream oil and gas projects. The findings show that in such a high-risk context, often an experienced executive makes these decisions alone and he creates value by facilitating growth. We identified three value-creating decision processes that varied by the executives’ risk approach and decision context. These processes depart from the formal project management prescriptions and the strategic decision-making literature.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2054
Author(s):  
Anna Fensel ◽  
Juan Miguel Gómez Berbís

Here, we overview the Energies journal special issue that is dedicated to the topic of “Energy Efficiency in Smart Homes and Smart Grids” (https://www [...]


Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1606 ◽  
Author(s):  
Weifeng Lin ◽  
Zhang Liu ◽  
Nir Kampf ◽  
Jacob Klein

Hydration lubrication has emerged as a new paradigm for lubrication in aqueous and biological media, accounting especially for the extremely low friction (friction coefficients down to 0.001) of articular cartilage lubrication in joints. Among the ensemble of molecules acting in the joint, phosphatidylcholine (PC) lipids have been proposed as the key molecules forming, in a complex with other molecules including hyaluronic acid (HA), a robust layer on the outer surface of the cartilage. HA, ubiquitous in synovial joints, is not in itself a good boundary lubricant, but binds the PC lipids at the cartilage surface; these, in turn, massively reduce the friction via hydration lubrication at their exposed, highly hydrated phosphocholine headgroups. An important unresolved issue in this scenario is why the free HA molecules in the synovial fluid do not suppress the lubricity by adsorbing simultaneously to the opposing lipid layers, i.e., forming an adhesive, dissipative bridge between them, as they slide past each other during joint articulation. To address this question, we directly examined the friction between two hydrogenated soy PC (HSPC) lipid layers (in the form of liposomes) immersed in HA solution or two palmitoyl–oleoyl PC (POPC) lipid layers across HA–POPC solution using a surface force balance (SFB). The results show, clearly and surprisingly, that HA addition does not affect the outstanding lubrication provided by the PC lipid layers. A possible mechanism indicated by our data that may account for this is that multiple lipid layers form on each cartilage surface, so that the slip plane may move from the midplane between the opposing surfaces, which is bridged by the HA, to an HA-free interface within a multilayer, where hydration lubrication is freely active. Another possibility suggested by our model experiments is that lipids in synovial fluid may complex with HA, thereby inhibiting the HA molecules from adhering to the lipids on the cartilage surfaces.


Author(s):  
Paul J. Pearson ◽  
David M. Bevly

This paper develops two analytical models that describe the yaw dynamics of a farm tractor and can be used to design or improve steering control algorithms for the tractor. These models are verified against empirical data. The particular dynamics described are the motions from steering angle to yaw rate. A John Deere 8420 tractor, outfitted with inertial sensors and controlled through a PC-104 form factor computer, was used for experimental validation. Conditions including different implements at varying depths, as would normally be found on a farm, were tested. This paper presents the development of the analytical models, validates them against empirical data, and gives trends on how the model parameters change for different configurations.


2011 ◽  
Vol 99 (6) ◽  
pp. 1139-1144 ◽  
Author(s):  
Bradford P. Roberts ◽  
Chet Sandberg
Keyword(s):  

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