Search results for "Losses"

INVERTER-BASED DISTRIBUTED GENERATORS, MODELING AND CONTROL

In the last few years, electrical power generation is moving from a centralized generation towards distributed generation including on-site Renewable Energy Sources (RESs). In order to overcome RES related issues, as intermittent and fluctuating power, storage elements are included in the on-site generation system. The interaction between distributed generator (DG) units including RES, storage and front-end power converters should be carefully modeled in order to analyze the power system stability. An accurate modeling of DGs is required. In this thesis, a new modeling approach has been proposed for the inverter-based DGs based on the concept of electrostatic synchronous machines. Detailed …

A Technical Approach to the Energy Blockchain in Microgrids

2018

The present paper considers some technical issues related to the “energy blockchain” paradigm applied to microgrids. In particular, what appears from the study is that the superposition of energy transactions in a microgrid creates a variation of the power losses in all the branches of the microgrid. Traditional power losses allocation in distribution systems takes into account only generators while, in this paper, a real-time attribution of power losses to each transaction involving one generator and one load node is done by defining some suitable indices. Besides, the presence of P–V nodes increases the level of reactive flows and provides a more complex technical perspective. For this re…

Space-vector State Dynamic Model of the SynRM Considering Self, Cross-Saturation and Iron Losses and Related Identification Technique

2023

This article proposes a space-vector dynamic model of the Synchronous Reluctance Motor (SynRM) including both self-saturation, cross-saturation effects, and iron losses. The model is expressed in state form, where the magnetizing current has been selected as a state variable. The proposed dynamic model is based on an original function describing the relationship between the stator flux and the magnetizing current components, improving a previously developed magnetic model. Additionally, the proposed model includes, besides the magnetic saturation, also iron losses. The proposed model requires 11 coefficients, among which 6 describe the self-saturation on both axes and 5 describe the cross-s…

Glossing the Old Frisian Psalter: Pragmatics and Competence

2014

The essay takes into examination the interlinear glosses in Old Frisian in the fragment of Psalter in ms. Groningen, Universiteitsbibliotheek 404. This is the oldest medieval Frisian fragmentary codex to survive and contains verses of Psalms XVII, XXVII, and XVIII, accompanied by glosses in the vernacular. This essay is the first lengthy study specifically devoted to the typology of the glosses themselves and their peculiarities (within the field of interlinear glosses). On close inspection, the OF glosses show a large internal coherence and individual quality. As far as the lexicon is concerned, the glosses feature a series of words belonging to the juridical lexicon, whereas other word-ch…

The Names of the ‘Pearl’ in the Old High German Glosses and Glossaries

2019

The essay will provide a scrutiny of the words merigrioz and perala occurring in the Old High German glosses to render the Latin words for ‘pearl’, i.e. unio and margarita, with the purpose of mapping the distribution and the contexts of use of the OHG words. The analysis will contribute to trace the origin of the German word for ‘pearl’, starting from the earliest stage of the language and – from a perspective of language contact – which takes into account the Latin counterparts of these OHG glosses.

Preface

2018

The essays collected in these two volumes provide evidence of Patrizia Lendinara’s wide expertise and her impact in distinct academic fields, ranging from late antiquity to the early and late Middle Ages. The papers are offered as a tribute to Patrizia’s scholarship by colleagues from Italy and abroad, some of whom were once her students. The theme of this Festschrift was chosen in view of the honouree’s keen interest in and contribution to the study of the glosses and the lexicon of Germanic languages. Accordingly, although the essays collected in these volumes vary quite widely in both style and structure, they all ultimately focus on the various facets of glossography and lexicography of…

Application of Mathematical Models in Analysis of Heat Losses in the Buildings

2006

Physical model of heat balance for separate living room is discussed, which allows to analyse the distributions of the flow of air and temperature depending on the physical conditions and geometry. The model enables to choose the optimal surface area of building elements and their properties in order to decrease the heat losses and improve the conditions of thermal comfort. Room with bounding constructions and real dimensions is modelled that helps to understand the peculiarities of heat transfer process in the room as well as distribution of various characteristic quantities and their dependence on the different conditions. Multiple parameters are varied in 2D calculations and their influe…

Space-vector State Dynamic Model of the Synchronous Reluctance Motor Considering Self, Cross-Saturation and Iron Losses

2021

This paper proposes a space-vector dynamic model of the Synchronous Reluctance Motor (SynRM) including both self-saturation, cross-saturation effects, and iron losses expressed in state form, where the magnetizing current has been selected as a state variable. The proposed dynamic model is based on an original function between the stator flux and the magnetizing current components, improving a previously developed magnetic model. Additionally, the proposed model includes, besides the magnetic saturation, also iron losses. The proposed model requires 11 coefficients, among which 6 describe the self-saturation on both axes and 5 describe the cross-saturation. Starting from the definition of a…

Assessment of MOSFET switching losses in an LLC converter by a calorimetric method

2023

The present work aims to implement a calorimetric method to measure the power dissipated during MOSFET switching in a high efficiency LLC resonant converter. The power dissipated from switching can significantly impact the total power dissipated by the device and consequent efficiency, so correct quantification is fundamental for optimizing the devices and increasing the efficiency of the converters. In LLC converters, this type of dissipated power cannot be measured with standard methods such as measurement with oscilloscopes as some of the energy that is recovered and not dissipated. The calorimetric method requires reasonably accurate measurement of thermal resistance and the temperature…

Le glosse testuali nell’insegnamento della L2: una prospettiva pedagogica moderna

2018

The promotion of the teaching / learning of the second / foreign language, starting from the use that is made of them in situational contexts of communication, has directed the course of language teaching research towards an approach to texts intended as spaces of not only linguistic knowledge, but communicative, as well as motivational springs capable of triggering the deepening of the language itself. From this point of view, the language class becomes the environment in which the teacher is a facilitator and an expert builder of learning texts. Hence the idea of reconsidering and enhancing the use of textual glosses, according to the learner-centred model, proposed in the 1980s by Wayne …