DC/DC pretvarači za motorne pogone – koncept, dizajn i unaprijedno upravljanje

Solar photovoltaics is one of the most promising technologies for the non-carbon based electricity production. Power electronics is therefore necessary. In this paper a converter is analyzed which makes it possible to control the mean value of the output voltage, this is e.g. the voltage across a DC machine (and therefore the speed) from zero up to three times of the input voltage. The converter is also useful for charging batteries. The model of the drive, the design of the devices, the control features are discussed, feed-forward control based on solving the limit cycle is designed, some experimental results, and hints for the design are given.Solarni paneli jedni su od najznačajnijih sustava za proizvodnju električne energije koja se ne temelji na ugljenu. U te svrhe nužno je korištenje učinske elektronike. U ovome radu analiziran je ispravljač koji omogućuje upravljanje srednjom vrijednosti izlaznog napona, tj. napona u odnosu na DC uređaj (stoga i upravljanje brzinom) u rasponu od nule pa do tri puta razine izlaznog napona. Ispravljač se također može koristiti za punjenje baterija. Model i dizajn uređaja zajedno sa sustavom upravljanja opisani su u radu. Prikazano je unaprijedno upravljanje temeljeno na rješavanju graničnih ciklusa, dani su eksperimentalni rezultati te su prikazane pojedinosti dizajniranja uređaja

Modelling The Digital Twin For Data-Driven Product Development - A Literature Review

Due to advanced connectivity and increasing distribution of product-service, more and more data is available from the products used and produced. Scientific publications often describe that this product data can be applied in product development to make it more efficient and that the digital twin can play a central role in data provision and interoperability. However, less attention is paid to how the digital twin should be designed for this purpose and how it should be adequately modelled for these use cases. Therefore, this paper presents a structured literature review to analyse which methods are already described in science to model digital twins in a target-oriented way for use cases of data-driven product development. Not only are the procedures interesting, but also the type of digital twin for which they are intended and whether they describe the procedure at the level of a rough macrostructure or detailed microstructure

Geologic framework of the northern North Carolina, USA inner continental shelf and its influence on coastal evolution

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Geology 348 (2014): 113-130, doi:10.1016/j.margeo.2013.11.011.The inner continental shelf off the northern Outer Banks of North Carolina was mapped using sidescan sonar, interferometric swath bathymetry, and high-resolution chirp and boomer subbottom profiling systems. We use this information to describe the shallow stratigraphy, reinterpret formation mechanisms of some shoal features, evaluate local relative sea-levels during the Late Pleistocene, and provide new constraints, via recent bedform evolution, on regional sediment transport patterns. The study area is approximately 290 km long by 11 km wide, extending from False Cape, Virginia to Cape Lookout, North Carolina, in water depths ranging from 6 to 34 m. Late Pleistocene sedimentary units comprise the shallow geologic framework of this region and determine both the morphology of the inner shelf and the distribution of sediment sources and sinks. We identify Pleistocene sedimentary units beneath Diamond Shoals that may have provided a geologic template for the location of modern Cape Hatteras and earlier paleo-capes during the Late Pleistocene. These units indicate shallow marine deposition 15–25 m below present sea-level. The uppermost Pleistocene unit may have been deposited as recently as Marine Isotope Stage 3, although some apparent ages for this timing may be suspect. Paleofluvial valleys incised during the Last Glacial Maximum traverse the inner shelf throughout the study area and dissect the Late Pleistocene units. Sediments deposited in the valleys record the Holocene transgression and provide insight into the evolutionary history of the barrier-estuary system in this region. The relationship between these valleys and adjacent shoal complexes suggests that the paleo-Roanoke River did not form the Albemarle Shelf Valley complex as previously proposed; a major fluvial system is absent and thus makes the formation of this feature enigmatic. Major shoal features in the study area show mobility at decadal to centennial timescales, including nearly a kilometer of shoal migration over the past 134 yr. Sorted bedforms occupy ~ 1000 km2 of seafloor in Raleigh Bay, and indicate regional sediment transport patterns between Capes Hatteras and Lookout that help explain long-term sediment accumulation and morphologic development. Portions of the inner continental shelf with relatively high sediment abundance are characterized by shoals and shoreface-attached ridges, and where sediment is less abundant, the seafloor is dominated by sorted bedforms. These relationships are also observed in other passive margin settings, suggesting a continuum of shelf morphology that may have broad application for interpreting inner shelf sedimentation patterns.Funding for this research was provided by the USGS Coastal and Marine Geology Program

Učinski izmjenjivač visoke djelotvornosti s posebnim istosmjernim međukrugom

In case of medium voltage (several tens up to hundred volts on DC-side) solar inverter applications, a DC-to-DC converter for voltage level adaptation is required in series of the DC-to-AC inverter. This leads to a two-stage concept with accumulation of the losses. In our case a concept was chosen where the efficiency of each stage is maximized by using the best topology. The given requirements make the application of a non-isolated design imperative to avoid additional transformer losses. In this paper a 60V–120V DC (input) to 230V AC (output) / 1kW converter with minimal conversion losses is derived. A simple modification in the inverter\u27s output section leads to a significant improvement of the losses in the inverter system. Only three additional components (two diodes and one inductor) are necessary to optimize the inverter\u27s power stage. The topology presented here shows a remarkable improvement of the switching losses and significantly reduced EMC. It is well-suited for solar power inverter applications.U slučajevima srednjenaponskih razina ulaznog napona (nekoliko desetaka do stotinu volti na istosmjernoj strani) izmjenjivača napajanih iz fotonaponskih ćelija, zahtjeva se istosmjerni pretvarač spojen u seriju s izmjenjivačem, za prilagodbu naponskih razina. Takav dvostupanjski pristup uzrokuje povećanje gubitaka. U ovom je slučaju odabran pristup kod kojeg se djelotvornost svakog stupnja pretvorbe maksimizira uporabom najpovoljnije topologije. Zadani zahtjevi čine obveznom uporabu istosmjernog pretvarača bez galvanskog odvajanja, da bi se izbjegli dodatni gubici u transformatoru. U ovom članku izveden je pretvarač snage 1 kW, ulaznog istosmjernog napona 60 V–120 V, izlaznog izmjeničnog napona 230V, s minimalnim gubicima pretvorbe. Jednostavna prilagodba u izlaznom stupnju izmjenjivača dovodi do značajnog smanjenja gubitaka u izmjenjivaču. Za optimiranje izlaznog stupnja izmjenjivača potrebne su samo 3 dodatne komponente (2 diode i prigušnica). Ovdje prikazana topologija pokazuje značajno smanjenje sklopnih gubitaka i smanjuje elektromagnetske smetnje. Posebno je pogodna za primjenu kod izmjenjivača napajanih iz fotonaponskih ćelija

Bridging The Gap: A Framework For Structuring The Asset Administration Shell In Digital Twin Implementation For Industry 4.0

The digital twin is a core technology for implementing Industry 4.0 scenarios in scientific and industrial applications. One upcoming variant of the digital twin is the concept of the asset administration shell, representing an approach to standardization. This approach must be adapted to specific use cases and applied in a target-oriented manner. However, no comprehensive guidance exists on structuring and implementing asset administration shells based on the digital twin in manufacturing environments. This issue pertains to defining and organizing the relevant data and mapping domain-specific limitations and characteristics within the hierarchical structure of the asset administration shell's components. This paper introduces an approach to structuring the asset administration shell to address this gap. This approach capitalizes on domain-specific expertise, industry standards, and established best practices, providing a framework. We validate the presented approach by applying it to the use case of distributed high-rate electrolyser production. The overarching objective of this research is to bridge the gap between theoretical concepts and practical applications

Conceptualizing A Digital Twin Based On The Asset Administration Shell For The Implementation Of Use Case Specific Digital Services

In the context of ongoing digitalization, manufacturing companies face new challenges and the need to expand their portfolios to include new digital services. Enriching their portfolio with digital services can be an opportunity for manufacturing companies to position themselves in emerging collaborative production networks and thus make their business model fit for the future. The paper ties in with the activities from the Product Lifecycle Enrichment as a Service (PLCEaaS) research project. Within this context, use cases for digital services have already been derived, modelled, and documented in various workshops. The respective digital services directly address external customers and internal stakeholders from development. The central enabler for the new digital services is the digital twin based on the asset administration shell, which makes the necessary data available and thus supports interoperability. The asset administration shell is enriched with use case-specific submodels. The procedure for structuring these submodels is shown in this paper using the research project as an example. This includes modelling the digital services with a standardized modelling language based on the semi-structured use cases described so far. As a result, we obtain an asset administration shell enriched with several submodels - some of which may be based on standardization activities already underway or represent proprietary submodels. Likewise, it is considered whether more submodels are required to implement the domain-specific use cases that are currently not yet addressed in standardization activities. The paper ends with an outlook on the further research activities that are necessary to prototype the planned project and describes which criteria can be used to evaluate the defined submodels in the later course of the project

Towards A Design Of A Software-Defined Manufacturing System Based On A Systematic Literature Review For Enabling A Decentralised High-Rate Electrolyser Production

Hydrogen is critical for the transition to an environmentally sound and reliable energy supply. This transition requires large capacities of performant and cost-effective electrolysers. Although performant electrolysers already exist, they cannot yet be manufactured at a high rate in series production. The project H2Giga-FRHY is researching a reference factory for large-scale production of electrolysers, developing new production and testing modules. As an essential building block of the reference factory, a research group at Fraunhofer IPA is designing and implementing a comprehensive software-defined manufacturing system (SDMS), which supports the decentralized high-rate production of electrolysers and allows for far-reaching insights regarding high-rate capability, quality, and cost of products, processes, and technologies involved. For the SDMS implementation, different enterprise architecture (EA) approaches are considered and evaluated in the scope of a structured literature review with respect to criteria arising from the project context and related research questions. In this paper, an approach to designing a software-defined manufacturing system is described, and its necessity is based on the use case-specific criteria discussed

Programm des K. Humanistischen Gymnasiums Dillingen a.D. : für das Schuljahr ... / Die Vogelwelt von Dillingen

von Michael HimmelstossErschienen: Teil 1-