Three phase four wire shunt active power filter from theory to industrial facility tests

Non-linear loads are very common in present industrial facilities, office buildings and even in our homes. This loads present several Power Quality problems to the electrical grid. The conventional solutions do not solve these problems in a suitable way. Therefore, it is necessary to find new solutions such as Active Power Filters. This paper presents and discusses the main steps that are necessary to implement a Three Phase Four Wire Shunt Active Power Filter from theory to field tests. Therefore it is a contribution on several topics. Starting with the main control theories used on this topology, it explains the p-q Theory in a more detailed way. It also gives a brief presentation of some modulation techniques. There are presented computational simulation results and field tests results of the developed filter operating in an industrial facility.Fundação para a Ciência e a Tecnologia (FCT

FPGA field oriented control of an axial flux motor-in-wheel

This paper presents the design and the prototype implementation of a three-phase power inverter developed to drive a motor-in-wheel. The control system is implemented in a FPGA (Field Programmable Gate Array) device. The paper describes the Field Oriented Control (FOC) algorithm and the Space Vector Modulation (SVM) technique that were implemented. The control platform uses a Spartan-3E FPGA board, programmed with Verilog language. Simulation and experimental results are presented to validate the developed system operation under different load conditions. Finally are presented conclusions based on the experimental results.FCT – Fundação para a Ciência e Tecnologia in the scope of the project: Pest-OE/EEI/UI0319/201

Evaluation of a shunt active power filter with energy backup capability

This paper presents a new Shunt Active Power Filter (SAPF) that is able to compensate current power quality problems and also to serve as energy backup to the loads in case of power outages. The paper describes the hardware topology, the control system of the SAPF, as well as the energy backup control scheme. Also it describes the power outage detection scheme to trigger the energy backup mode, as well as the grid synchronization after the power restoration. To assess the behavior of the SAPF when compensating power quality problems in transient and steady-state, and during the operation as energy backup system, several simulations were performed.This work is financed by FEDER Funds, through the Operational Programme for Competitiveness Factors – COMPETE, and by National Funds through FCT – Foundation for Science and Technology of Portugal, under the projects PTDC/EEA-EEL/104569/2008 and FCOMP-01-0124-FEDER022674.info:eu-repo/semantics/publishedVersio

Assessment of a battery charger for electric vehicles with reactive power control

Batteries of Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs) have a large potential not only to provide energy for the locomotion of these vehicles, but also to interact, in dynamic way, with the power grid. Thereby, through the energy stored in the batteries, these vehicles can be used to regulate the active and the reactive power, as local Energy Storage Systems. This way, EVs can contribute to help the power grid to regulate the active and reactive power flow in order to stabilize the production and consumption of energy. For this propose should be defined usage profiles, controlled by a collaborative broker, taking into account the requirements of the power grid and the conveniences of the vehicle user. Besides, the interface between the power grid and the EVs, instead of using typical power converters that only work on unidirectional mode, need to use bidirectional power converters to charge the batteries (G2V - Grid-to-Vehicle mode) and to deliver part of the stored energy in the batteries back to the power grid (V2G - Vehicle-to-Grid mode). With the bidirectional power converter topology presented in this paper, the consumed current is sinusoidal and it is possible to regulate the power factor to control the reactive power, aiming to contribute to mitigate power quality problems in the power grid. To assess the behavior of the presented bidirectional power converter under different scenarios, are presented some computer simulations and experimental results obtained with a prototype that was developed to be integrated in an Electric Vehicle.Fundação para a Ciência e a Tecnologia (FCT) - FCOMP-01-0124-FEDER-022674, PTDC/EEAEEL/ 104569/2008, MIT-PT/EDAM-SMS/0030/2008.FEDER Funds, through the Operational Programme for Competitiveness Factors (COMPETE

Bidirectional battery charger with grid-to-vehicle, vehicle-to-grid and vehicle-to-home technologies

This paper presents the development of na on-board bidirectional battery charger for Electric Vehicles (EVs) targeting Grid-to-Vehicle (G2V), Vehicle-to-Grid (V2G), and Vehicle-to-Home (V2H) technologies. During the G2V operation mode the batteries are charged from the power grid with sinusoidal current and unitary power factor. During the V2G operation mode the energy stored in the batteries can be delivered back to the power grid contributing to the power system stability. In the V2H operation mode the energy stored in the batteries can be used to supply home loads during power outages, or to supply loads in places without connection to the power grid. Along the paper the hardware topology of the bidirectional battery charger is presented and the control algorithms are explained. Some considerations about the sizing of the AC side passive filter are taken into account in order to improve the performance in the three operation modes. The adopted topology and control algorithms are accessed through computer simulations and validated by experimental results achieved with a developed laboratory prototype operating in the different scenarios

Phytosociology and floristic diversity in a cerrado area under different antropization levels, rio pardo de Minas, MG

Este estudo teve como objetivo avaliar a diversidade e a similaridade flor\uedstica de ambientes de Cerrado, sob diferentes n\uedveis de antropiza\ue7\ue3o por uso agr\uedcola e extrativismo, e gerar base de dados para subsidiar propostas de desenvolvimento sustent\ue1vel para a regi\ue3o Norte de Minas e sistemas de agricultura tradicional. Foram amostradas 4 \ue1reas nos seguintes ambientes: Arei\ue3o, Arei\ue3ozinho, Chapada de Latossolo e Tabuleiro, cujas identifica\ue7\uf5es foram feitas a partir de informantes-chave na Comunidade \uc1gua Boa, em Rio Pardo de Minas (MG). As unidades amostrais foram distribu\ueddas em 8 parcelas de 20 x 50 m, com 5 subparcelas. Foram medidos indiv\uedduos arb\uf3reos com circunfer\ueancia ao n\uedvel do solo maior ou igual a 15 cm. Para an\ue1lise dos \uedndices fitossociol\uf3gicos foram calculados os par\ue2metros densidade, domin\ue2ncia, freq\ufc\ueancia, \ue1rea basal e valor de import\ue2ncia, para cada ambiente. Para a diversidade flor\uedstica foi calculado o \uedndice de Shannon (H\u2019) e para an\ue1lise da similaridade o \uedndice de Jaccard (Sij). Em todos os ambientes, foi encontrado um total de 477 indiv\uedduos, distribu\ueddos em 21 fam\uedlias, com 48 esp\ue9cies bot\ue2nicas identificadas e 27 indiv\uedduos n\ue3o identificados. As cinco fam\uedlias mais importantes (maior VI) foram Fabaceae/Papilionoideae, Apocynaceae, Vochysiaceae, Sapotaceae e Fabaceae/Caesalpinoideae. J\ue1 as dez esp\ue9cies de maior import\ue2ncia foram Pouteria ramiflora, Dalbergia miscolobium, Hancornia speciosa, Macherium opacum, Sclerolobium paniculatum var. subvelutinum, Qualea grandiflora, Aspidosperma tomentosum, Byrsonima pachyphylla, Vochysia thyrsoidea e Hymenaea stigonocarpa. O \uedndice H\u2019 foi de 3,01; 2,72; 2,48 e 2,09 para Arei\ue3o, Arei\ue3ozinho, Chapada do Latossolo e Tabuleiro, respectivamente. O \uedndice Sij indicou, para todas as combina\ue7\uf5es entre os ambientes, que existia pouca similaridade flor\uedstica entre eles.The objective of the study was to evaluate diversity and floristic similarity of Cerrado environments, under different levels of anthropization for agricultural usage and extractivism, and to generate a database to subsidize sustainable development proposals for the North region of Minas Gerais State, and traditional agriculture systems. Four areas with different levels of anthropization were sampled, in the following environments: "Arei\ue3o, Arei\ue3ozinho, Chapada de Latossolo and Tabuleiro", whose identifications had been made from key informers in the \uc1gua Boa Community, in Rio Pardo de Minas (MG, Brazil). The sampled units were distributed in 8 parcels of 20 x 50 m, with 5 subplots. The trees with circumference at ground level of 15 cm or bigger were measured. For analysis of the phytosociology indexes the following parameters were calculated for each environment: density, dominance, frequency, basal area, and importance value. For the floristic diversity the Shannon (H') was calculated, and for the analysis of similarity the index of Jaccard index (Sij). In all the environments, it was found a total of 477 individuals, distributed in 21 families, with 48 botanical species identified, and 27 individuals not identified. The five most important (importance value) families was Fabaceae/Papilionoideae, Apocynaceae, Vochysiaceae, Sapotaceae and Fabaceae/Caesalpinoideae. And the ten most important species was Pouteria ramiflora, Dalbergia miscolobium, Hancornia speciosa, Macherium opacum, Sclerolobium paniculatum var. subvelutinum, Qualea grandiflora, Aspidosperma tomentosum, Byrsonima pachyphylla, Vochysia thyrsoidea and Hymenaea stigonocarpa. The H' index was of 3.01; 2.72; 2.48 and 2.09 for "Arei\ue3o, Arei\ue3ozinho, Chapada de Latossolo and Tabuleiro", respectively. The Sij index indicated a small floristic similarity for all the combinations between the environments

Lower production of IL-17A and increased susceptibility to Mycobacterium bovis in mice coinfected with Strongyloides venezuelensis

The presence of intestinal helminths can down-regulate the immune response required to control mycobacterial infection. BALB/c mice infected with Mycobacterium bovis following an infection with the intestinal helminth Strongyloides venezuelensis showed reduced interleukin-17A production by lung cells and increased bacterial burden. Also, small granulomas and a high accumulation of cells expressing the inhibitory molecule CTLA-4 were observed in the lung. These data suggest that intestinal helminth infection could have a detrimental effect on the control of tuberculosis (TB) and render coinfected individuals more susceptible to the development of TB

Differential expression of follistatin and FLRG in human breast proliferative disorders

<p>Abstract</p> <p>Background</p> <p>Activins are growth factors acting on cell growth and differentiation. Activins are expressed in high grade breast tumors and they display an antiproliferative effect inducing G0/G1 cell cycle arrest in breast cancer cell lines. Follistatin and follistatin- related gene (FLRG) bind and neutralize activins. In order to establish if these activin binding proteins are involved in breast tumor progression, the present study evaluated follistatin and FLRG pattern of mRNA and protein expression in normal human breast tissue and in different breast proliferative diseases.</p> <p>Methods</p> <p>Paraffin embedded specimens of normal breast (NB - n = 8); florid hyperplasia without atypia (FH - n = 17); fibroadenoma (FIB - n = 17); ductal carcinoma <it>in situ </it>(DCIS - n = 10) and infiltrating ductal carcinoma (IDC - n = 15) were processed for follistatin and FLRG immunohistochemistry and <it>in situ </it>hybridization. The area and intensity of chromogen epithelial and stromal staining were analyzed semi-quantitatively.</p> <p>Results</p> <p>Follistatin and FLRG were expressed both in normal tissue and in all the breast diseases investigated. Follistatin staining was detected in the epithelial cytoplasm and nucleus in normal, benign and malignant breast tissue, with a stronger staining intensity in the peri-alveolar stromal cells of FIB at both mRNA and protein levels. Conversely, FLRG area and intensity of mRNA and protein staining were higher both in the cytoplasm and in the nucleus of IDC epithelial cells when compared to NB, while no significant changes in the stromal intensity were observed in all the proliferative diseases analyzed.</p> <p>Conclusion</p> <p>The present findings suggest a role for follistatin in breast benign disease, particularly in FIB, where its expression was increased in stromal cells. The up regulation of FLRG in IDC suggests a role for this protein in the progression of breast malignancy. As activin displays an anti-proliferative effect in human mammary cells, the present findings indicate that an increased FST and FLRG expression in breast proliferative diseases might counteract the anti-proliferative effects of activin in human breast cancer.</p