Search results for "MPP+"

Parental agency and related emotions in the educational partnership

2017

This study investigated the understudied issue of parental agency and related emotions in the educational partnership in the context of Finnish early childhood education and care. We asked (i) what types of parental agency can be identified in the educational partnership and (ii) in what ways emotions are related to these types of agency. The narrative method was used to analyse the interview data of parents of children with difficulties in self-regulation. The findings indicate that parental agency in the educational partnership varied from proactive and confrontational to hindered. Typically, pleasant emotions were related to proactive and unpleasant emotions to confrontational parental a…

A standard-compliant prototype for PV module curve detection

2014

In this paper, a prototype for PV module curve detection which features low cost and size and ensures high accuracy is proposed. The proposed architecture is based on a buck-boost converter in open-loop configuration. The proposed architecture is fully compliant with actual standard IEC60904. The duty-cycle control algorithm and its own effects on system performances are accurately investigated. The comparison of different duty-cycle patterns is carried out and performance evaluation is performed. Simulation results are shown to perform a valuable comparison of control algorithms. Preliminary experimental results on a laboratory prototype are presented.

Analytical Investigation and Control System Set-up of Medium Scale PV Plants for Power Flow Management

2012

In the field of photovoltaic (PV) plants and energy conversion from renewable sources, a large part of the technical literature is more devoted to practical aspects (new solar cells, electrically driven PV panels, safety, reduction of parasitic currents, etc.) than to theoretical investigations. Despite this tendency, this paper presents a mathematical analysis of a medium scale photovoltaic power generation system connected to the distribution network and of its control system. In such a system, the conversion stage is unique due to the absence of a boost chopper. The conducted analysis leads to the interesting conclusion that the inverter used in the plant presents two degrees of freedom,…

Optimization of photovoltaic energy production through an efficient switching matrix

2013

This work presents a preliminary study on the implementation of a new system for power output maximization of photovoltaic generators under non-homogeneous conditions. The study evaluates the performance of an efficient switching matrix and the relevant automatic reconfiguration control algorithms. The switching matrix is installed between the PV generator and the inverter, allowing a large number of possible module configurations. PV generator, switching matrix and the intelligent controller have been simulated in Simulink. The proposed reconfiguration system improved the energy extracted by the PV generator under non-uniform solar irradiation conditions. Short calculation times of the pro…

Numerical Analysis of Medium Scale PV Plants and Their Power-Flow Control System With a Simple Three Phase Inverter

2012

This paper presents a mathematical analysis of a medium scale Photovoltaic (PV) power generation system connected to the distribution network and of its control system, in which the conversion stage is unique thanks to the absence of a boost chopper. Boost choppers are usually used as actuator for maximum power point tracking (MPPT). The conducted analysis leads to the conclusion that the used inverter presents two degrees of freedom that can be easily exploited in a control system in which the inverter simultaneously realizes the interconnection to the grid and at the same time realizes the MPPT control. The structure of the control system is then presented, discussed and then validated by…

Phonon Driven Floquet Matter.

2018

The effect of electron–phonon coupling in materials can be interpreted as a dressing of the electronic structure by the lattice vibration, leading to vibrational replicas and hybridization of electronic states. In solids, a resonantly excited coherent phonon leads to a periodic oscillation of the atomic lattice in a crystal structure bringing the material into a nonequilibrium electronic configuration. Periodically oscillating quantum systems can be understood in terms of Floquet theory, which has a long tradition in the study of semiclassical light-matter interaction. Here, we show that the concepts of Floquet analysis can be applied to coherent lattice vibrations. This coupling leads to p…

‘Strong and courageous’ but ‘constantly insecure’: dialogical self theory, intersecting identities, and Christian mixed martial arts

2021

Being a mixed martial arts fighter and a devout Christian seems to present an apparent contradiction that requires identity work to bring these identities into unity. We used Dialogical Self Theory and explored the autobiography of Ron ‘H2O’ Waterman, a professional fighter turned evangelist, to understand how the tensions between the different identities or I-positions were negotiated. We identified two I-positions, ‘Ron the Fighter’ and ‘Ron the Pater Familias’, which related differently to religion, sport, and masculinity. Importantly, the negotiations were not between MMA and faith, but between these two I-positions that served the different needs for self-enhancement and union with som…

Genomics and Proteomics Analyses Revealed Novel Candidate Pesticidal Proteins in a Lepidopteran-Toxic Bacillus thuringiensis Strain

2020

Discovery and identification of novel insecticidal proteins in Bacillus thuringiensis (Bt) strains are of crucial importance for efficient biological control of pests and better management of insect resistance. In this study, the Bt strain KhF, toxic for Plodia interpunctella and Grapholita molesta larvae, underwent genomics and proteomics analyses to achieve a better understanding of the bases of its pathogenicity. The whole-genome sequencing results revealed that the KhF strain contained nine coding sequences with homologies to Bt insecticidal genes. The lepidopteran toxic mixture of spores and crystals of this Bt strain was subjected to liquid chromatography and tandem mass spectrometry …

Kalmbergin kartasto R IV : List 9

1855

Reconfigurable electrical interconnection strategies for photovoltaic arrays: A review

2014

Non-uniform irradiance significantly decreases the power delivered by solar photovoltaic arrays. A promising technique for compensating these power losses relies on dynamically reconfiguring the electrical connections between photovoltaic modules. This paper presents the current state-of-the-art strategies for photovoltaic array reconfiguration in order to increase the power output under partial shading and mismatch conditions. The different approaches have been compared in terms of effectiveness of the control algorithms, monitored electrical and environmental variables, overall hardware complexity and specific features of each solution. Finally, the most challenging aspects of the reconfi…