Steady-state mathematical models of convertors with biparametric regulation

1993 ◽  
Vol 140 (2) ◽  
pp. 105
Author(s):  
G. Carpinelli ◽  
F. Gagliardi ◽  
A. Sturchio ◽  
M. Russo
Keyword(s):  
Steady State ◽  
Mathematical Models

Electron drift caused by rf field gradient creates many plasma phenomena: An attempt to distinguish the cause and the effect

2011 ◽  
Vol 78 (2) ◽  
pp. 165-174 ◽  
Author(s):  
C. L. XAPLANTERIS ◽  
E. D. FILIPPAKI ◽  
I. S. MISTAKIDIS ◽  
L. C. XAPLANTERIS
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Low Temperature ◽  
Mathematical Models ◽  
Field Gradient ◽  
Collision Frequency ◽  
The Other ◽  
Frequency Effect ◽  
Electron Drift ◽  
Plasma Parameters

AbstractMany experimental data along with their theoretical interpretations on the rf low-temperature cylindrical plasma have been issued until today. Our Laboratory has contributed to that research by publishing results and interpretative mathematical models. With the present paper, two issues are being examined; firstly, the estimation of electron drift caused by the rf field gradient, which is the initial reason for the plasma behaviour, and secondly, many new experimental results, especially the electron-neutral collision frequency effect on the other plasma parameters and quantities. Up till now, only the plasma steady state was taken into consideration when a theoretical elaboration was carried out, regardless of the cause and the effect. This indicates the plasma's complicated and chaotic configuration and the need to simplify the problem. In the present work, a classification about the causality of the phenomena is attempted; the rf field gradient electron drift is proved to be the initial cause.

scholarly journals INCREASING THE EFFICIENCY OF ELECTRIC DRIVES WITH PERIODICAL LOADING BY USING COMPREHENSIVE MATHEMATICAL MODELING MEANS

2021 ◽  
Author(s):  
Olena Bibik ◽  
◽  
Oleksandr Popovich ◽  
Keyword(s):  
Mathematical Modeling ◽  
Energy Efficiency ◽  
Steady State ◽  
Optimal Design ◽  
Mathematical Models ◽  
Quasi Steady State ◽  
Periodic Load ◽  
Electromechanical Systems ◽  
Periodic Loading ◽  
Asynchronous Motors

The mode of operation of induction motors (IMs) affects their performance. In most cases, motors are optimally designed for steady state operation. When operating in other modes, additional attention is required to the problems of energy efficiency. Induction motors are the most common type of electromechanical energy converters, and a significant part of them operate under conditions of periodic changes in the load torque. The work is devoted to solving the problem of increasing the energy efficiency of asynchronous motors of electromechanical systems with a periodic load, including pumping and compressor equipment. The traditional solution to this problem for compressor equipment is the optimal design of an IM under static conditions, as well as the use of flywheels, the use of an IM with an increased slip value and controlled IM with a squirrel-cage rotor and with frequency converters. In this work, the modes of operation of asynchronous motors with periodic loading are investigated. For this, complex mathematical models are developed in the simulation system. Such models are effective in modeling taking into account periodic load changes: repetitive transient processes, their possible asymmetry and non-sinusoidality, increased influence of nonlinearity of electromagnetic parameters. In complex mathematical modeling, the mutual influence of the constituent parts of the electromechanical system is taken into account. Simulation allowed quantifying the deterioration in energy efficiency under intermittent loading, in comparison with static modes. Criteria for evaluating quasi-static modes have been developed and areas of critical decrease in efficiency have been determined. The paper proposes and demonstrates a methodology for solving this problem. For this purpose, tools have been created for the optimal design of asynchronous motors as part of electromechanical systems with periodic loading. These tools include: complex mathematical models of electromechanical systems with asynchronous motors with periodic load, mathematical tools for determining the parameters of quasi-steady-state modes, the methodology of optimal design based on the criterion of the maximum efficiency of processes under quasi-steady-state modes of operation. The possibilities, advantages and prospects of using the developed mathemati-cal apparatus for solving a number of problems to improve the efficiency of electric drives of compressor and pumping equipment are demonstrated. It is shown that by taking into account quasi-static processes, the use of complex mathematical models for the optimal design of asynchronous motors with a periodic load provides an in-crease in efficiency up to 8 ... 10%, relative to the indicators of motors that are de-signed without taking into account the quasi-static modes. The areas of intense quasi-steady-state modes are determined using the devel-oped criterion. In these areas, there is a critical decrease in efficiency compared to continuous load operation. A decrease in efficiency is associated with a decrease in the amount of kinetic energy of the rotating parts compared to the amount of electromagnetic energy. In connection with the development of a frequency-controlled asynchronous drive of mechanisms with a periodic load, the relevance of design taking into account the peculiarities of quasi-static has increased significantly. For example, a variable frequency drive of a refrigerator compressor or a heat pump can increase energy efficiency up to 40%, but at low speeds, due to a decrease in kinetic energy, the efficiency can decrease to 10 ... 15%, unless a special design methodology is applied. This problem can be solved by using the complex mathematical modeling tools developed in the article.

Steady-state mathematical models of battery storage plants with line-commutated converters

1993 ◽  
Vol 8 (2) ◽  
pp. 494-503 ◽  
Author(s):  
G. Carpinelli ◽  
F. Gagliardi ◽  
M. Russo ◽  
A. Sturchio
Keyword(s):  
Steady State ◽  
Mathematical Models ◽  
Battery Storage

Research of Tight Band Coiling Dynamics

2006 ◽  
Vol 113 ◽  
pp. 271-276
Author(s):  
Vytautas Kepalas ◽  
Česlovas Ramonas ◽  
Stanislovas Marcinkevičius ◽  
Romualdas Konstantinas Masteika
Keyword(s):  
Steady State ◽  
Mathematical Models ◽  
Transient Response ◽  
Relative Elongation ◽  
Block Diagram ◽  
Digital Model ◽  
Tension Force ◽  
Elastic Band ◽  
Response Curves ◽  
Matlab Simulink

Purpose of the work is to analyze tight band coiling machine dynamics for processing wire, thread, texture, paper, leatherette or other elastic bands with a steady-state tension force. Band coiling block diagram and mathematical models for cases with one and two regulators has been made for research of elastic band coiling processing using software MATLAB-SIMULINK. Transient response curves of linear speeds in the band feed section and in a coiling machine, of band tension force and of relative elongation are presented. The digital model was used for obtaining parameters of controllers when parameters of feedback and regulators have been changing.

scholarly journals Theoretical and Experimental Evaluation of Thermal Resistance for Compression Bandages

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
A. R. Aboalasaad ◽  
B. K. Sirková ◽  
T. Mansoor ◽  
Z. Skenderi ◽  
A. S. Khalil
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
Mathematical Models ◽  
Experimental Evaluation ◽  
Theoretical Models ◽  
Compression Bandage ◽  
Compression Bandages

AbstractThe objective of this paper is to report a study on the prediction of the steady-state thermal resistance of woven compression bandage (WCB) by using three different mathematical models. The experimental samples of WCB were 100% cotton, cotton–polyamide–polyurethane, and viscose–polyurethane. The bandage samples were evaluated at extensions ranging at 10–100%, with two- and three-layer bandaging techniques. Experimental thermal resistance was measured by thermal foot manikin (TFM) and ALAMBETA testing devices. The obtained results by TFM and ALAMBETA were validated and compared with the theoretical models (Maxwell–Eucken2, Schuhmeister, and Militky), and a reasonable correlation of approximately 78%, 92%, and 93% for ALAMBETA and 75%, 82%, and 83% for TFM, respectively, was observed.

scholarly journals A Dual-Aggressive Model of Tumor-Immune System Interactions

2019 ◽  
Vol 15 (10) ◽  
pp. 155
Author(s):  
Abdulkareem Ibrahim Afolabi ◽  
Normah Maan
Keyword(s):  
Steady State ◽  
Immune System ◽  
Numerical Analysis ◽  
Mathematical Models ◽  
Malignant Tumor ◽  
Physical Phenomenon ◽  
Biomedical Literature ◽  
The Stability ◽  
Total Elimination ◽  
Insight Into

<p class="0abstract">Biomedical literature suggested that the tumor-immune system physical phenomenon usually climaxes into either tumor elimination or escape. In retort to the phenomenological mechanics of tumor-immune system interaction, researchers had used Mathematical models mostly prey-predator and competitive extensively, to model the dynamics of tumor immune system interaction. However, these models had not accounted for total elimination and, or escape of tumor as hypothesizes by immunoediting hypotheses. In this work, we propose a dual aggressive model based on the biological narration of tumor-immune system interactions. The stability analyses of tumor-negative steady state are stable if the rate at which body cells dies is less than their proliferation rate a confirmation of biological listed causes of the tumor. The tumor-positive steady state is always unstable and saddle with the likelihood of either elimination or escape of tumor. Numerical analysis validates our analytical results and provides insight into the dynamics of the benignant and malignant tumor. The immunosuppression by tumor is not only visible but also validated by both analytical and numerical analysis.</p>

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