Experiences in Teaching Electric Drives Based on Basic Modelling Simulations and Industrial A.C. Drive Measurements

2010 ◽  
Vol 47 (4) ◽  
pp. 416-429
Author(s):  
A. Molina-García ◽  
E. Gómez ◽  
J. A. Fuentes ◽  
J. Villarejo
Keyword(s):  
Electric Drive ◽  
Laboratory Tests ◽  
Theoretical Knowledge ◽  
Electric Drives ◽  
The Past ◽  
Basic Model ◽  
Student Reaction ◽  
Simulation Results ◽  
Four Quadrant ◽  
And Control

The objective of this paper is to compare laboratory tests of industrial electric a.c. drives and simulation results obtained from the basic model introduced to our students in practical sessions. This basic model takes into account the electrical, electronic and control subsystems which comprise a simplified electric a.c. drive. The proposed tests allow us to analyse the electric drive in four-quadrant operation, which are included in this paper. The main advantage of this approach is that students can verify the differences between real and simulated results and, in this way, they can also progress, strengthen and expand their theoretical knowledge. The proposed methodology has been implemented during the past few years in two optional subjects related to electric and electronic fields. Academic results and student reaction are also discussed.

SIMULATION OF SOFT START OF SYNCHRONOUS ELECTRIC DRIVES

2019 ◽  
Author(s):  
Shakhboz Dadabaev
Keyword(s):  
Computer Simulation ◽  
Electric Drive ◽  
Water Supply Systems ◽  
Factors Affecting ◽  
Electric Drives ◽  
Soft Start ◽  
Simulation Results ◽  
Pumping Units ◽  
Negative Factors ◽  
Supply Systems

The main negative factors affecting the starting modes of synchronous electric drives of pumping units of irrigation water supply systems were identified, computer simulation of direct and soft start of synchronous electric drive was made, the simulation results are shown in graphs and a brief conclusion was made on the study.

scholarly journals MATHEMATICAL SIMULATION OF INDUCTION MOTOR SCALAR CONTROL SYSTEM

2021 ◽  
Author(s):  
Viktor Marus ◽  
Aleksandr Pugachev
Keyword(s):  
Energy Efficiency ◽  
Control System ◽  
Mathematical Simulation ◽  
Control Systems ◽  
Induction Motor ◽  
Electric Drive ◽  
Electric Drives ◽  
Scalar Control ◽  
Simulation Results

The simulation results of 4 kW induction motor electric drive with scalar control system and different control topologies are presented. The perspective directions of further investigations on improving energy efficiency of electric drives with scalar control systems are highlighted.

Dynamics of the macromolecular composition of the biomass of microalgae in the morning under natural light. Model

2020 ◽  
pp. 45-52
Author(s):  
Alexander S. Lelekov ◽  
Anton V. Shiryaev
Keyword(s):  
Biochemical Composition ◽  
Initial Conditions ◽  
Natural Light ◽  
Photoautotrophic Growth ◽  
Structural Part ◽  
Basic Model ◽  
Microalgae Culture ◽  
Simulation Results ◽  
Structural Parts ◽  
Macromolecular Composition

The work is devoted to modeling the growth of optically dense microalgae cultures in natural light. The basic model is based on the idea of the two-stage photoautotrophic growth of microalgae. It is shown that the increase in the intensity of sunlight in the first half of the day can be described by a linear equation. Analytical equations for the growth of biomass of microalgae and its macromolecular components are obtained. As the initial conditions, it is assumed that at the time of sunrise, the concentration of reserve biomass compounds is zero. The simulation results show that after sunrise, the growth of the microalgae culture is due only to an increase in the reserve part of the biomass, while the structural part practically does not change over six hours. Changes in the ratio of the reserve and structural parts of the biomass indicate a change in the biochemical composition of cells.

ELECTRIC DRIVE, ITS CONDITION AND PROSPECTS

2020 ◽  
Author(s):  
N.D. Kobzeva ◽  
◽  
R.S. Durov ◽  
E.V. Varnakova ◽  
K.O. Kobzev ◽  
...  
Keyword(s):  
Electric Drive ◽  
The State ◽  
Electric Drives

The known definitions for the concept of "electric drive"are given. The analysis of the state of electric drives in Russia is made. The requirements imposed on them are stated. The main criteria for improvement and development are formulated.

On-Surface Radical Oligomerisation: A New Approach to STM Tip-Induced Reactions

2018 ◽  
Author(s):  
Gaolei Zhan ◽  
Younes Makoudi ◽  
Judicael Jeannoutot ◽  
Simon Lamare ◽  
Michel Féron ◽  
...  
Keyword(s):  
Sample Surface ◽  
Scanning Tunnelling Microscope ◽  
Transfer Event ◽  
New Approach ◽  
The Past ◽  
Organic Nanostructures ◽  
Scanning Tunnelling ◽  
New Strategy ◽  
Surface Fabrication ◽  
And Control

Over the past decade, on-surface fabrication of organic nanostructures has been widely investigated for the development of molecular electronic devices, nanomachines, and new materials. Here, we introduce a new strategy to obtain alkyl oligomers in a controlled manner using on-surface radical oligomerisations that are triggered by the electrons/holes between the sample surface and the tip of a scanning tunnelling microscope. The resulting radical-mediated mechanism is substantiated by a detailed theoretical study. This electron transfer event only occurs when <i>V</i><sub>s</sub> < -3 V or <i>V</i><sub>s</sub> > + 3 V and allows access to reactive radical species under exceptionally mild conditions. This transfer can effectively ‘switch on’ a sequence leading to formation of oligomers of defined size distribution due to the on-surface confinement of reactive species. Our approach enables new ways to initiate and control radical oligomerisations with tunnelling electrons, leading to molecularly precise nanofabrication.

scholarly journals Ten-year trends of hypertension treatment and control rate in Korea

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kwang-il Kim ◽  
Eunjeong Ji ◽  
Jung-yeon Choi ◽  
Sun-wook Kim ◽  
Soyeon Ahn ◽  
...  
Keyword(s):  
Age Groups ◽  
Favorable Effect ◽  
Age Group ◽  
Hypertension Treatment ◽  
Treatment Rate ◽  
Cross Sectional ◽  
The Past ◽  
Nationally Representative ◽  
Multistage Sampling ◽  
And Control

AbstractWe analyzed the Korean National Health and Nutrition Examination Survey (KNHANES) database to determine the trends of hypertension treatment and control rate in Korea over the past 10 years. In addition, we tried to investigate the effect of chronic medical conditions on hypertension management. We investigated the hypertension prevalence, awareness, treatment, and control rate from 2008 to 2017. KNHANES, which uses a stratified multistage sampling design, is a cross-sectional, nationally representative survey conducted by the Korean government. A total of 59,282 adults (≥ 20 years) were included, which was representative of the total population of around 40 million Koreans per year. The mean age was 50.7 ± 16.4 years and 42.6% were male. The prevalence of hypertension, hypercholesterolemia, diabetes mellitus, and obesity significantly increased over the 10 years. During this period, the hypertension treatment and control rate significantly improved. Hypertension treatment rate was significantly lower in the younger age group compared to the older age group, but the control rate among the treated patients was not significantly different between age groups. The treatment and control rates of hypertension were higher in patients with multimorbidity, which implies that it has a favorable effect on the treatment and control of hypertension. Hypertension treatment and control rate have improved over the past 10 years. The higher treatment and control rate in patients with multimorbidity suggest that the more aggressive surveillance might be associated with the improvement of hypertension treatment and control rate in Korea.

Model development and control of an auto-refrigerated polystyrene polymerization reactor

2021 ◽  
pp. 014233122110251
Author(s):  
Reyhane Mokhtarname ◽  
Ali Akbar Safavi ◽  
Leonhard Urbas ◽  
Fabienne Salimi ◽  
Mohammad M Zerafat ◽  
...  
Keyword(s):  
Temperature Control ◽  
Model Development ◽  
Heat Removal ◽  
Superior Performance ◽  
Polymerization Process ◽  
Vacuum System ◽  
Control Scheme ◽  
Simulation Results ◽  
And Control ◽  
Operating Plant

Dynamic model development and control of an existing operating industrial continuous bulk free radical styrene polymerization process are carried out to evaluate the performance of auto-refrigerated CSTRs (continuous stirred tank reactors). One of the most difficult tasks in polymerization processes is to control the high viscosity reactor contents and heat removal. In this study, temperature control of an auto-refrigerated CSTR is carried out using an alternative control scheme which makes use of a vacuum system connected to the condenser and has not been addressed in the literature (i.e. to the best of our knowledge). The developed model is then verified using some experimental data of the real operating plant. To show the heat removal potential of this control scheme, a common control strategy used in some previous studies is also simulated. Simulation results show a faster dynamics and superior performance of the first control scheme which is already implemented in our operating plant. Besides, a nonlinear model predictive control (NMPC) is developed for the polymerization process under study to provide a better temperature control while satisfying the input/output and the heat exchanger capacity constraints on the heat removal. Then, a comparison has been also made with the conventional proportional-integral (PI) controller utilizing some common tuning rules. Some robustness and stability analyses of the control schemes investigated are also provided through some simulations. Simulation results clearly show the superiority of the NMPC strategy from all aspects.

scholarly journals An Introduction to Development of Centralized and Distributed Stochastic Approximation Algorithm with Expanding Truncations

Algorithms ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 174
Author(s):  
Wenxiao Zhao
Keyword(s):  
Approximation Algorithm ◽  
Stochastic Approximation ◽  
Probabilistic Method ◽  
Principal Component ◽  
Stochastic Approximation Algorithm ◽  
The Past ◽  
Systems And Control ◽  
Ode Method ◽  
Centralized Algorithm ◽  
And Control

The stochastic approximation algorithm (SAA), starting from the pioneer work by Robbins and Monro in 1950s, has been successfully applied in systems and control, statistics, machine learning, and so forth. In this paper, we will review the development of SAA in China, to be specific, the stochastic approximation algorithm with expanding truncations (SAAWET) developed by Han-Fu Chen and his colleagues during the past 35 years. We first review the historical development for the centralized algorithm including the probabilistic method (PM) and the ordinary differential equation (ODE) method for SAA and the trajectory-subsequence method for SAAWET. Then, we will give an application example of SAAWET to the recursive principal component analysis. We will also introduce the recent progress on SAAWET in a networked and distributed setting, named the distributed SAAWET (DSAAWET).

The Origins of Domestic Sheep and Goats: a Reconsideration in the Light of the Fossil Evidence

1969 ◽  
Vol 34 ◽  
pp. 368-384 ◽  
Author(s):  
Sebastian Payne
Keyword(s):  
Direct Evidence ◽  
Present Situation ◽  
Wild Relatives ◽  
The Other ◽  
Domestic Sheep ◽  
Sheep And Goats ◽  
Animal Domestication ◽  
The Past ◽  
The One ◽  
And Control

In recent discussions of the origins and process of animal domestication (Reed, 1961, Zeuner, 1963), both authors rely on two kinds of evidence: on the one hand, the present distributions and characteristics of the different breeds of whatever animal is being discussed, together with its feral and wild relatives, and, on the other hand, the past record, given by literary and pictorial sources and the bones from archaeological and geological sites. Increased recognition of the limitations of the past record, whether in the accuracy of the information it appears to give (as in the case of pictorial sources), or in the certainty of the deductions we are at present capable of drawing from it (this applies especially to the osteological record), has led these authors to argue mainly from the present situation, using the past record to confirm or amplify the existing picture.Arguing from the present, many hypotheses about the origins and process of domestication are available. The only test we have, when attempting to choose between these, lies in the direct evidence of the past record. The past record, it is freely admitted, is very fragmentary: the information provided by the present situation is more exact, ranges over a much wider field, and is more open to test and control. Nevertheless, the past record, however imperfect it is, is the only direct evidence we have about the process of domestication.

A multigroup model for cholera dynamics and control

2015 ◽  
Vol 09 (01) ◽  
pp. 1650001 ◽  
Author(s):  
Drew Posny ◽  
Chairat Modnak ◽  
Jin Wang
Keyword(s):  
Reproduction Number ◽  
Vaccination Strategy ◽  
Sharp Threshold ◽  
Indirect Transmission ◽  
Dynamics And Control ◽  
Simulation Results ◽  
Transmission Pathways ◽  
And Control ◽  
Control Study ◽  
The Basic Reproduction Number

We propose a general multigroup model for cholera dynamics that involves both direct and indirect transmission pathways and that incorporates spatial heterogeneity. Under biologically feasible conditions, we show that the basic reproduction number R0 remains a sharp threshold for cholera dynamics in multigroup settings. We verify the analysis by numerical simulation results. We also perform an optimal control study to explore optimal vaccination strategy for cholera outbreaks.

Sign in / Sign up

Export Citation Format

Share Document