Impact of electric vehicles on power quality in a smart grid context

The large dependency of the imported fossil fuels and the soaring oil prices, makes essential the look for alternatives to the traditional people transportation system. The natural bet is the electric mobility, namely Electric Vehicles (EV), and Plug-in Hybrid Electric Vehicles (PHEV). This way, in this paper is analyzed the potential impacts of the battery charging systems on the grid power quality, in a Smart Grid context. It is considered the current consumed, according to a typical electric consumption profile, and the voltage degradation for a large number of houses. Two different types of EV batteries chargers were considered: a traditional charger; and a smart charger with sinusoidal current consumption and unitary power factor. It presents simulation results of the integration of EVs and PHEVs in terms of power quality, and experimental results of a smart charger which was specially developed for EV charging and that allows mitigation of the power quality degradation.Fundação para a Ciência e a Tecnologia (FCT

Batteries charging systems for electric and plug-in hybrid electric vehicles

Many countries have a large dependence on imported fossil fuels whose prices increase almost every day. Knowing that much of this consumption is for transportation systems, it becomes essential to seek for alternatives. The natural bet is the electric mobility, namely through Electric Vehicles (EVs) and Plug-in Hybrid Electric Vehicles (PHEVs). However, the wide spread utilization of these vehicles has consequences on the electrical power grid, mainly in terms of load management and electric power quality, which are associated to the batteries charging systems. In this scenario, this chapter assesses the electric mobility integration in Smart Grid context, focusing different approaches to the operation of EVs and PHEVs charging processes and the specifications of the chargers, as well as different topologies of charging systems and their features, modes of operation, typical waveforms, and impact in the electrical power grid in terms of power quality. It is also presented a laboratory prototype of a bidirectional EV charger and shown some experimental results. This prototype was developed to charge the batteries aiming to preserve their lifespan, and to contribute to mitigate the degradation of the power quality. The experimental results show the operation of this prototype during the batteries charging process (G2V – Grid-to-Vehicle operation), and during the delivering of stored energy back to the electrical power grid (V2G – Vehicle-to-Grid operation).FEDER Funds - Operational Program for Competitiveness Factors – COMPETEFundação para a Ciência e a Tecnologia (FCT) - FCOMP-01-0124-FEDER-022674, MITPT/ EDAM-SMS/0030/200

Disseminated Well-Differentiated Gastro-Entero-Pancreatic Tumors Are Associated with Metabolic Syndrome

The association of well-differentiated gastro-entero-pancreatic neuroendocrine tumors (WD GEP-NETs) with metabolic syndrome (MetS), abdominal obesity, and fasting glucose abnormalities was recently described. The aim of this study was to evaluate whether the presence of MetS or any MetS individual component was also influenced by GEP-NET characteristics at diagnosis. A cohort of patients with WD GEP-NETs (n = 134), classified according to primary tumor location (gastrointestinal or pancreatic), pathological grading (G1 (Ki67 ≤ 2%) and G2 (>3 ≤ 20%) (WHO 2010), disease extension (localized, loco-regional, and metastatic), and presence of hormonal secretion syndrome (functioning/non-functioning), was evaluated for the presence of MetS criteria. After adjustment for age and gender, the odds of having MetS was significantly higher for patients with WD GEP-NET grade G1 (OR 4.35 95%CI 1.30–14.53) and disseminated disease (OR 4.52 95%CI 1.44–14.15). GEP-NET primary tumor location or secretory syndrome did not influence the risk for MetS. None of the tumor characteristics evaluated were associated with body mass index, fasting plasma glucose category, or any of the individual MetS components. Patients with GEP-NET and MetS depicted a higher risk of presenting a lower tumor grade and disseminated disease. The positive association between MetS and GEP-NET characteristics further highlights the potential link between the two conditions.This work did not receive any funding either from public, commercial, or nonprofit agencies

Assessing microcirculation dynamics during gait in the lower limb - a preliminary approach

Gait is a daily life activity that requires a permanent combination between skeletal muscle mechanical stimuli with other hemodynamic systems, such as the regulation of blood flow. This is a preliminary study to identify the potential adaptations occurring in the lower limb microcirculation during loading and suspension phases of gait. Six subjects (25.8 ± 5.4) were evaluated during a protocol performed in three phases: 1 minute of both feet support, 1 minute of light steps in the same place and 1 minute similar to the initial phase. Skin microcirculation was noninvasively assessed by the Tissue Viability Imaging® System (TiVi) in both feet (expressed in AU’s). Pulse rate (PR) was measured with a photoplethysmography system (PPG). Descriptive and comparative statistics were applied, and a confidence level of 95% adopted. Our preliminary data detected a physiological variation during gait in the suspension phase of stepping, compared with the loading phase. When the foot is cyclically on the floor, the values are similar to the resting phase. Further studies are needed to look deeper into the microvascular behaviour on the lower limb during the gait cycle

Influence of estimated training status on anti and pro-oxidant activity, nitrite concentration, and blood pressure in middle-aged and older women

The purpose of this study was to compare the association between anti and pro-oxidant activity, nitrite concentration, and blood pressure (BP) in middle-aged and older women with different levels of estimated training status (TS). The sample consisted of 155 females (50-84 years) who were submitted to a physical examination to evaluate estimated TS through the "Functional Fitness Battery Test," BP measurements, and plasma blood samples to evaluate pro-oxidant and antioxidant activity and nitrite concentrations. Participants were separated by age into a middle-aged group (< 65 years) and an older (≥65 years) group and then subdivided in each group according to TS. Blood biochemistry was similar between groups. On the other hand, protein oxidation was lower in participants with higher TS, independent of age. Older females with higher TS presented higher nitrite concentrations, lower lipoperoxidation, and lower values of BP compared with those with lower TS. Lower GPx activity was observed in participants with higher TS compared with middle-aged with lower TS. Thus, our results suggest that good levels of TS may be associated with lower oxidative stress and higher nitrite concentration and may contribute to maintain normal or reduced blood pressure values.Fil: Jacomini, André M.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Dias, Danielle da Silva. Universidade Nove de Julho; BrasilFil: Brito, Janaina de Oliveira. Universidade Nove de Julho; BrasilFil: da Silva, Roberta F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Monteiro, Henrique L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Llesuy, Susana Francisca. Universidade Nove de Julho; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: De Angelis, Kátia. Universidade Nove de Julho; BrasilFil: Amaral, Sandra L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Zago, Anderson S.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

A case study on the conversion of an internal combustion engine vehicle into an electric vehicle

This paper presents the conversion process of a traditional Internal Combustion Engine vehicle into an Electric Vehicle. The main constitutive elements of the Electric Vehicle are presented. The developed powertrain uses a three-phase inverter with Field Oriented Control and space vector modulation. The developed on-board batteries charging system can operate in Grid-to-Vehicle and Vehicle-to-Grid modes. The implemented prototypes were tested, and experimental results are presented. The assembly of these prototypes in the vehicle was made in accordance with the Portuguese legislation about vehicles conversion, and the main adopted solutions are presented.FCT – Fundação para a Ciência e Tecnologia in the scope of the project: PEst - OE/EEI/UI0319/201

Field oriented control of an axial flux permanent magnet synchronous motor for traction solutions

Electric Vehicles (EVs) are increasingly used nowadays, and different powertrain solutions can be adopted. This paper describes the control system of an axial flux Permanent Magnet Synchronous Motor (PMSM) for EVs powertrain. It is described the implemented Field Oriented Control (FOC) algorithm and the Space Vector Modulation (SVM) technique. Also, the mathematical model of the PMSM is presented. Both, simulation and experimental, results with different types of mechanical load are presented. The experimental results were obtained using a laboratory test bench. The obtained results are discussed.F CT – Fundação para a Ciência e Tecnologia in the scope of the project: PEst - OE/EEI/UI0319/201

Comparing passive leg raising and suprasystolic ankle occlusion responses to quantify age-related microcirculatory status

The skin provides an easy accessible vascular network to assess microcirculation by laser Doppler flowmetry (LDF), and transcutaneous (tc) gasometry, widely known techniques used for this purpose. the objective of this study was to assess and compare the microcirculation status of different age subjects, knowing that the ageing process progressively affects macro and microcirculatory vessels. We’ve chosen to compare dynamical responses to two provocation tests – passive leg raising (PLR) and ankle occlusion - in 59 healthy subjects, 35 young (22.1 ± 3.7 years old.) in Group 1, and 24 older (50.8 ± 7.6 years old.) in Group 2, selected after informed consent. Local blood flow, tcpO2 and transepidermal water loss (TEWL) were measured in distal locations of the lower limb. PLR and ankle occlusion significantly reduced blood flow and tcpO2 in both groups, while no changes were found for TEWL. While the magnitude of the hyperemic response was found to be significantly reduced in group 2, no differences were found during ankle occlusion. tcpO2-dependent parameters were also significantly different between groups. These results seem to confirm the usefulness of these experimental models to distinguish the microcirculatory function of subjects with different ages, with PLR being more sensible in detecting age-related changes

Exploring human in vivo microcirculation with methyl nicotinate in different perfusion conditions

Noninvasive technologies, such as Laser Doppler Flowmetry (LDF) and transcutaneous (tc) gasimetry, are useful to assess microcirculation physiology in vivo. Provocation tests, often involving drugs, change perfusion conditions, evoking dynamical responses and respective quantification. Methyl nicotinate (MN) is potent vasodilator, commonly used to test skin reactivity. The purpose of this study was to investigate the cutaneous microvascular reactivity to MN on the lower limb under different perfusion conditions. The MN-induced vasodilation was recorded in the foot of 15 healthy (23.1 ± 3.0) years old subjects in two protocols – (1) MN application in a seated position while breathing room atmosphere and while breathing a saturated oxygen atmosphere; (2) MN application while in a supine position and during leg elevation. Several curve-dependent parameters were compared for each protocol by the Wilcoxon matched pairs signed ranks test. A 95 % confidence level was adopted. Results showed no difference in the magnitude of vasodilation when breathing an oxygen atmosphere or a room atmosphere. However, the magnitude of vasodilation decreased significantly when the subject performed a leg elevation from a supine position. Results suggests the usefulness of this model, including MN, to test cutaneous microcirculatory reactivity in vivo