A Concise History of Induction Motor Drives—Part 2 [History]

©2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioimaton|en=nonPeerReviewed

Design and Performance Evaluation of SMC-Based DC–DC Converters for Microgrid Applications

In recent times, DC microgrids (MGs) have received significant attention due to environmental concerns and the demand for clean energies. Energy storage systems (ESSs) and photovoltaic (PV) systems are parts of DC MGs. This paper expands on the modeling and control of non-isolated, non-inverting four-switch buck-boost (FSBB) synchronous converters, which interface with a wide range of low-power electronic appliances. The proposed power converter can work efficiently both independently and in DC MGs. The charging and discharging of the battery are analyzed using the FSBB converter at a steady state in continuous conduction mode (CCM). A boost converter is connected to a PV system, which is then connected in parallel to the battery to provide voltages at the DC bus. Finally, another FSBB converter is connected to a resistive load that successfully performs the boost-and-buck operation with smooth transitions. Since these power converters possess uncertainties and non-linearities, it is not suitable to design linear controllers for these systems. Therefore, the controlling mechanism for these converters’ operation is based on the sliding mode control (SMC). In this study, various macro-level interests were achieved using SMC. The MATLAB Simulink results successfully prove the precise reference tracking and robust stability in different operating modes of DC–DC converters in a MG structure.© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Cooperative Control of Multi-Master-Slave Islanded Microgrid with Power Quality Enhancement Based on Conservative Power Theory

Made available in DSpace on 2018-11-26T16:04:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-07-01Cooperative control of power converters in a microgrid offers power quality enhancement at sensitive load buses. Such cooperation is particularly important in the presence of reactive, nonlinear, and unbalanced loads. In this paper, a multi-master-slave-based control of distributed generators interface converters in a three-phase four-wire islanded microgrid using the conservative power theory (CPT) is proposed. Inverters located in close proximity operate as a group in master- salve mode. Slaves inject the available energy and compensate selectively unwanted current components of local loads with the secondary effect of having enhanced voltage waveforms while masters share the remaining load power autonomously with distant groups using frequency droop. The close proximity makes it practical for control signals to be communicated between inverters in one group with the potential to provide rapid load sharing response for mitigation of undesirable current components. Since each primary source has its own constraints, a supervisory control is considered for each group to determine convenient sharing factors. The CPT decompositions provide decoupled current and power references in abc-frame, resulting in a selective control strategy able to share each current component with desired percentage among the microgrid inverters. Simulation results are presented to demonstrate the effectiveness of the proposed method.Colorado Sch Mines, Dept EECS, Golden, CO 80401 USAAalborg Univ, Dept Energy Technol, DK-9220 Aalborg, DenmarkPetr Inst, Dept Elect Engn, Abu Dhabi 2533, U Arab Emirate

Avaliação funcional multivariada em jogadores de futebol profissional: uma metanálise

O objetivo deste trabalho foi verificar, de modo amplo, o comportamento de variáveis importantes para a saúde preventiva e o desempenho atlético, em jogadores de futebol profissional. Além disso, o estudo tece comentários, através de longa revisão bibliográfica, sobre os resultados de nossos atletas e os observados na literatura especializada, nessa modalidade esportiva. Os futebolistas foram submetidos a uma bateria de testes clínicos, laboratoriais e de aptidão cardiorespiratória, metabólica e muscular, pré-participação ao Campeonato Brasileiro de Futebol de 1996, que constou das seguintes variáveis: consumo de oxigênio, limiar anaeróbio ventilatório, eletrocardiografia em repouso e no exercício, potência muscular ( wingate), flexibilidade, hemograma, reações sorológicas para doença de Chagas, protoparasitológico, glicose, uréia, creatinina, colesterol total e frações, hormônios, eletrólitos, minerais, composição corporal, avaliação fisioterápica, odontológica e nutricional. Os resultados obtidos indicaram que o emprego de uma avaliação multifatorial, em atletas de alto rendimento, é um procedimento importante para verificar se o nível de aptidão física está adequado e/ou detectar possíveis deficiências, que possam interferir no desempenho atlético dos futebolistas, durante os treinamentos e jogos

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Oliver Heaviside’s Operational Calculus : The Foundations of Electrical Engineering [History]

Toward the end of the 19th century, Oliver Heaviside developed a formal calculus of differential operators to solve various physical problems. Oliver Heaviside was the man who wrote, for the first time in the history of science, the now-so-called Maxwell’s Four Laws of Electricity and Magnetism. Maxwell published his two-volume work, A Treatise on Electricity and Magnetism, in 1873.©2024 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioimaton|en=nonPeerReviewed

Frequency Support of Smart Grid Using Fuzzy Logic-Based Controller for Wind Energy Systems

This paper proposes a fuzzy logic-based controller for a wind turbine system to provide frequency support for a smart grid. The designed controller is aimed to provide an appropriate dynamic droop rate depending on the local measurements of each wind turbine of a wind farm such as the maximum power available and the amount of power reserve. The designed fuzzy controller depends on the rate of change of frequency (ROCOF) at the point of common coupling (PCC). The main advantage of the proposed fuzzy controller is to provide frequency support by the wind turbine system connected to a smart grid. The dynamic rate of the controller is defined by the fuzzy sets considering the change in the grid’s frequency and the available reserve power. First, the response of static droop curves is investigated for different scenarios of wind turbines connected to a smart grid. Then, the proposed fuzzy logic-based droop controller is integrated into the system, and its performance and response are evaluated, and the results are compared with static-droop based controller. The proposed controller is tested using Matlab\Simulink

Current Balancing Algorithm for Three-Phase Multilevel Current Source Inverters

In high power, medium voltage applications, Current Source Inverters CSIs are connected in parallel to accommodate high DC currents. Using a proper multilevel modulation technique, parallel-connected CSIs can operate as a Multilevel CSI (MCSI). The most common modulation technique for MCSIs is the Phase-Shifted Carrier SPWM (PSC-SPWM). The proper operation of the MCSI requires each CSI modules to have the same average current flowing through its sharing inductors. In practice, the average currents of the CSI modules deviate from their nominal values. Therefore, current balancing mechanisms must be implemented. In the literature, several solutions have been proposed to tackle the current imbalance problem. Most of these solutions are based on altering the phase-shift or magnitude of the carrier waveforms of the PSC-SPWM. They require dedicated PI controllers and they are applicable to MCSIs with specific numbers of levels. This paper proposes a Current Balancing Algorithm (CBA) that can be implemented in any MCSI with any number of levels. The proposed CBA does not require any PI controllers, nor does it require any alteration to the PWM carrier waveforms. The CBA is implemented using a modified Level-Shifted SPWM (LS-PWM). The modified LS-SPWM is shown to produce lower THD and lower di/dt when compared to the PSC-SPWM. The CBA and modified LS-SPWM where implemented in a proof-of-concept lab prototype. The experimental results are presented for the five-level and seven-level cases

Education in Electrification for Societal Sustainability : History and philosophy

We all depend on electricity, and as such, we define a mapping of electrification onto education because we all need a provision of life sustained by infrastructure that is powered by electricity. Electrification began at the end of the 19th century, becoming global, but is not yet complete. It is evolving, and in the last few decades, electrical power systems have undergone a reenchantment, a paradigm shift associated with renewable energy sources, energy storage systems, power electronics, modernization of communication, and automation of infrastructures. This article starts with several concepts and boundaries that have transformed electrical energy from a somewhat simple technology to the recent acceleration of the development process. We also look at how current and future pedagogical perspectives for the 21st-century electrical engineer will help us to become a sustainable society.©2024 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed