Search results for "module"

A novel approach for parameters determination in four lumped PV parametric model with operative range evaluations

2013

The paper presents a novel numerical approach for the parameters determination of crystalline silicon PV models four lumped parameters equivalent circuit. The novel approach basically deals with a new method, alternative to the iterative one known in literature, to calculate the series resistance. Particularly, it allows the evaluation of the lumped parameters on the basis of the manufacturer’s datasheet. The new approach has been validated both in the Maximum Power Point (MPP) and close to it by comparing values and curves obtained by means of the model implementation in Matlab/Simulink environment with those related to some five parameters models and manufacturer curves. Results show that…

Power quality effects on the measurement of reactive power in three-phase power systems in the light of the IEEE Standard 1459–2000.

2007

Reactive power is a very important quantity in electric power systems since it affects the efficiency of these systems. Also, capacitive loads can produce over-voltages in electric transformers by Ferranti effect, which produces bad power quality, so it is necessary to measure the reactive power correctly. In this paper reactive phenomena in three-phase power systems with unbalanced voltages are expressed and measured in the light of the IEEE Std 1459-2000. For analyzing the reactive phenomena the positive-sequence fundamental frequency instantaneous reactive power is used. By comparing the expressions of this instantaneous power in three-phase systems with unbalanced voltages with those co…

Direct sunlight facility for testing and research in HCPV

2014

A facility for testing different components for HCPV application has been developed in the framework of "Fotovoltaico ad Alta Efficienza" (FAE) project funded by the Sicilian Regional Authority (PO FESR Sicilia 2007/2013 4.1.1.1). The testing facility is equipped with an heliostat providing a wide solar beam inside the lab, an optical bench for mounting and aligning the HCPV components, electronic equipments to characterize the I-V curves of multijunction cells operated up to 2000 suns, a system to circulate a fluid in the heat sink at controlled temperature and flow-rate, a data logging system with sensors to measure temperatures in several locations and fluid pressures at the inlet and ou…

IRREDUCIBLE COXETER GROUPS

2004

We prove that a non-spherical irreducible Coxeter group is (directly) indecomposable and that an indefinite irreducible Coxeter group is strongly indecomposable in the sense that all its finite index subgroups are (directly) indecomposable. Let W be a Coxeter group. Write W = WX1 × ⋯ × WXb × WZ3, where WX1, … , WXb are non-spherical irreducible Coxeter groups and WZ3 is a finite one. By a classical result, known as the Krull–Remak–Schmidt theorem, the group WZ3 has a decomposition WZ3 = H1 × ⋯ × Hq as a direct product of indecomposable groups, which is unique up to a central automorphism and a permutation of the factors. Now, W = WX1 × ⋯ × WXb × H1 × ⋯ × Hq is a decomposition of W as a dir…

Power system consumption model using SPICE

2014

Space missions have very stringent mass, volume and also power budgets. This requires very precise knowledge of the power consumption of the whole satellite, not only peak power but also static and long term dynamic power. This calculation becomes very complex if all the operational modes (long term dynamic changes) are taken into account, including the different environmental situations. The power budget of any Power Converter Module (PCM), which includes not only the DC/DC converter but also the distribution unit, depends on the power it delivers and on external factors like temperature and input voltage. We propose to use a linear SPICE model using electronic models of discrete component…

Annihilators of tensor density modules

2007

Abstract We describe the two-sided ideals in the universal enveloping algebras of the Lie algebras of vector fields on the line and the circle which annihilate the tensor density modules. Both of these Lie algebras contain the projective subalgebra, a copy of sl 2 . The restrictions of the tensor density modules to this subalgebra are duals of Verma modules (of sl 2 ) for Vec ( R ) and principal series modules (of sl 2 ) for Vec ( S 1 ) . Thus our results are related to the well-known theorem of Duflo describing the annihilating ideals of Verma modules of reductive Lie algebras. We find that, in general, the annihilator of a tensor density module of Vec ( R ) or Vec ( S 1 ) is generated by …

Surfaces of minimal degree of tame representation type and mutations of Cohen–Macaulay modules

2017

We provide two examples of smooth projective surfaces of tame CM type, by showing that any parameter space of isomorphism classes of indecomposable ACM bundles with fixed rank and determinant on a rational quartic scroll in projective 5-space is either a single point or a projective line. For surfaces of minimal degree and wild CM type, we classify rigid Ulrich bundles as Fibonacci extensions. For the rational normal scrolls S(2,3) and S(3,3), a complete classification of rigid ACM bundles is given in terms of the action of the braid group in three strands.

On the Lattice of F-Dnormal Subgroups in Finite Soluble Groups

2001

Postępy w fotowoltanice w Polsce i na świecie = Progress in photovoltaics in Poland and the world

2015

W artykule przedstawiono postęp w zakresie uzyskiwanych sprawności przez ogniwa i moduły fotowoltaiczne (PV) wykonane z różnych materiałów i za pomocą różnych technologii. Zawarto w nim szczegółowe zestawienia tabelaryczne sprawności oraz ich parametrów technicznych. Zwrócono uwagę na nowe obiecujące technologie, które jeszcze nie mają rekordowych sprawności, ale z uwagi na proces ich wytwarzania rokują nadzieje na uzyskanie bardzo dużych sprawności albo tanich wielkopowierzchniowych modułów do komercyjnego zastosowania. Ponadto, omówiono ekonomiczne skutki wdrożenia nowo zawartych zapisów w uchwalonej w lutym 2015 r. Ustawie o Odnawialnych Źródłach Energii (OZE) dla rozwoju rozproszonych i…

Comparison between Different Dynamic Reconfigurations of Electrical Connections for partially shaded PV Modules

2018

This paper presents an economical investigation on the benefits related to the employment of reconfiguration systems for photovoltaic plants. More in detail, different structures of reconfigurators are proposed and, in order to evaluate the economical convenience on their installation, the Net Present Value is used as a validation element. Significant results are carried out from the proposed analysis.