2022 № 1 Електротехніка і Електромеханіка

Постійне посилання колекціїhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/65913

Переглянути

Зараз показуємо 1 - 10 з 10

On the electromagnetic shielding properties of carbon fiber materials
(Національний технічний університет "Харківський політехнічний інститут", 2022) Rosu, Georgiana; Velicu, Valentin; Boitan, Alexandru; Mihai, George; Tuta, Leontin; Baltag, Octavian
Due to the good electrical and thermal properties of carbon, carbon-based materials represent a major trend is various applications, including electromagnetic compatibility. Among carbon-based materials, graphite-impregnated woven fabrics represent a new trend in the field of electromagnetic shielding, with the perspective of being used for protective clothing. The novelty of the proposed work consists in the exhaustive comparative analysis of various carbon-based sample shields by employing both simulation and experimental methods. The selected configurations included a simple graphite plate, a graphite powder strip network, and a graphite-impregnated fabric with 2х2 twill weave. Purpose. The main scope of the analysis is to prove the efficiency of the graphite-impregnated twill woven fabric in the field of electromagnetic shielding. Methods. Two main research methods were employed: simulation and experiment, both following the same protocol: the shield placed in the middle, with the excitation (transmitting antenna) on one side and the measurement / receiving antenna on the other. The experimental stage was thorough, being performed in two different laboratories and by applying the double transverse electromagnetic (TEM) cell method and the shielded box method. Results. A significant difference yielded from the comparison of the simulation and experimental results for the shielding effectiveness, probably due to the fact that the virtual model is an idealized version of the physical one, not taking into account its imperfections. The virtual analysis yielded the graphite plate shield as the most efficient, followed closely by the twill fabric. The graphite strip network had significantly poorer performance compared to the other two shields, probably due to the electrical contact imperfections between the graphite strips and the optical transparency of the shield. The main focus of the analysis was the twill woven graphite-impregnated fabric; therefore, its shielding effectiveness was determined through simulation and experiment. The experimental analysis was performed in two stages in two different electromagnetic compatibility laboratories, by employing the double TEM cell method and the shielded box method, respectively, both methods providing similar results and classifying the shielding performance as good. Practical value. The paper provides an accurate analysis of the graphite-impregnated 2х2 twill woven fabric in terms of electromagnetic shielding effectiveness, by employing both simulation and experimental methods, and comparing its performance to the one other graphite-based shields.
Improvement of power transformer differential protection through detection and exploitation of the negative sequence currents
(Національний технічний університет "Харківський політехнічний інститут", 2022) Zitouni, Mokhtar
Power transformers are the most important and the most expensive equipment used in transport and distribution of electrical energy. Their failure results in huge economic losses. Despite the great advances in the design of power equipment in recent years, the feeble link in the chain remains the insulation weakness of coil turns of the power transformer. The novelty of the proposed research consists in the development of a new procedure for diagnosing and localizing the occurrence of turn to turn short-circuits in the windings of three-phase power transformer. The main problems of the current differential relay are short circuits of one or more turns of a transformer winding. Hence a new approach using' the amplitude comparison between the negative sequence currents' is developed and a digital discriminator internal / external fault is applied to discriminate turn to turn faults among the other ones. The proposed procedure is based on the exploitation of the negative sequence currents. The purpose of using this new procedure is to identify small faults inside power transformer coils and to distinguish inner faults from the outer faults by using an ameliorate circuit. The method used in this paper is a novel algorithm which based on the comparison between the negative sequence current amplitudes and to calculate the corresponding phase angle shifts. The performance of the proposed procedure has been confirmed by MATLAB/Simulink environment. The results of simulation reveal the efficiency of the suggested procedure, and indicate that this procedure can provide fast and sensitive approach for detecting low level turn-to-turn faults.
Непряме полеорієнтоване керування двошнековим електромеханічним гідролізером
(Національний технічний університет "Харківський політехнічний інститут", 2022) Заблодський, Микола Миколайович; Плюгін, Владислав Євгенович; Ковальчук, Станіслав Ігорович; Тєтєрєв, Віталій Олегович
У статті детально розглянуто конструктивні і електромагнітні особливості нестандартного електромеханічного перетворювача енергії – двошнекового електромеханічного гідролізера. Це технічний пристрій з поліфункціональними властивостями, здатний одночасно нагрівати, диспергувати, транспортувати, перемішувати та піддавати впливу магнітним полем в одному пристрої робочу сировину. Розроблено коло-польові та математичні моделі електромагнітних перехідних процесів цього пристрою. Основні параметри електромеханічної системи визначено шляхом кінцево-елементного моделювання та практичного дослідження феромагнітного ротора. В роботі представлено керування обертовим моментом та кутовою швидкістю феромагнітного ротора двошнекового електромеханічного гідролізера шляхом непрямого полеорієнтованого керування. Шляхом реалізації MATLAB / Simulink моделі отримано графічні залежності основних параметрів феромагнітного ротора за умов ступінчатої зміни обертового моменту та циклічної зміни кутової швидкості. За результатами моделювання помітно доцільність застосування методу непрямого керування з орієнтацією на поле для ефективного керування технологічним процесом двошнекового електромеханічного гідролізера. В порівнянні з розглянутими методами керування, непряме керування з орієнтацією на поле більш просте в проектуванні та реалізації, дозволяє досягнути бажаних характеристик та відкриває подальші можливості для дослідження двошнекового електромеханічного гідролізера.
Power quality improvement in distribution system based on dynamic voltage restorer using PI tuned fuzzy logic controller
(Національний технічний університет "Харківський політехнічний інститут", 2022) Gopal Reddy, Sanepalle; Ganapathy, Somaskandan; Manikandan, Mani
This article proposes a new control strategy for Dynamic Voltage Restorer (DVR) in utility grid for distribution system. The proposed DVR using PI tuned fuzzy logic scheme is based on replacement of conventional DVR and voltage sag compensation in distribution system network. The novelty of the proposed work consists in presenting an enhanced PI tuned fuzzy logic algorithm to control efficiently the dynamic voltage restorer when voltage sag is suddenly occurred. Methods. The proposed algorithm which provides sophisticated and cost-effective solution for power quality problems. Our strategy is based on tuned fuzzy control of reactive powers and also closed loop for harmonic reduction in distribution system. The proposed control technique strategy is validated using MATLAB / Simulink software to analysis the working performances. Results. The results obtained clearly show that DVR using PI tuned fuzzy logic have good performances (sag compensation, harmonic reduction) compared to conventional DVR. Originality. Compensation of voltage sag/ swell in distribution for reactive power and current harmonic reduction by using DVR based PI tuned fuzzy logic controller. Practical value. The work concerns the comparative study and the application of DVR based on PI tuned fuzzy techniques to achieve a good performance control system of the distribution system. This article presents a comparative study between the conventional DVR control and PI tuned fuzzy DVR control. The strategy based on the use of a PI tuned fuzzy controller algorithm for the control of the continuous voltage sag and harmonic for the distribution network-linear as well as non-linear loads in efficient manner. The study is validated by the simulation results based on MATLAB / Simulink software.
Performance enhancement of direct torque control induction motor drive using space vector modulation strategy
(Національний технічний університет "Харківський політехнічний інститут", 2022) Moussaoui, Leila
The main objective of this work is to demonstrate the advantages brought by the use of space vector modulation technique in the direct torque control of the induction motor. To achieve this purpose, two different direct torque control approaches (with space vector modulation) are proposed and studied from a comparative aspect with each other and with the conventional direct torque control. The novelty of this work consists in the employment of an Integral-Proportional (IP) speed controller in the two proposed direct torque control approaches and a more in-depth evaluation for their performance mainly the switching frequency of inverter semiconductor components and motor torque ripples. Methods. Two different direct torque control approaches that use the space vector modulation strategy and/or fuzzy-logic control, are described in detail and simulated with IP speed controller. The simulation experiments are carried out using Matlab/Simulink software and/or fuzzy-logic tools. Results. Practical value. Comparison results show that the two proposed direct torque control structures (with space vector modulation) exhibit a large reduction in torque ripples and can also avoid random variation problem of switching frequency (over a wide range of speed or torque control). On the other hand, the use of IP speed regulator ensured good dynamic performance for the drive system as well as considerably minimized peak overshoot in the speed response. Practically all of these benefits are achieved while retaining the simplicity and the best dynamic characteristics of the classical direct torque control, especially with the modified direct torque control approach in which the design or implementation requires minimal computational effort.
Simulation-based analysis of dynamic voltage restorer with sliding mode controller at optimal voltage for power quality enhancement in distribution system
(Національний технічний університет "Харківський політехнічний інститут", 2022) Zahra, Syeda Tahreem; Khan, Rizwan Ullah; Ullah, Mian Farhan; Begum, Balqees; Anwar, Naveed
Nowadays, power quality issues are of considerable interest to both utilities and end users as they cause significant financial losses to the industrial customers. Due to this, power quality assurance in power distribution systems is very important, when considering commercial and industrial applications. Problem Statement. Unfortunately, sudden faults such as sag, transients, harmonics distortion and notching in the power system create disturbances and affect the load voltages. Out of these, voltage sag and harmonics seriously affect sensitive devices. Harmonics in the power system cause increased heating of equipment and conductors, misfires in variable speed drives, and torque pulsations in motors. Harmonics reduction is considered desirable. Methodology. This paper presents an efficient and robust solution to this problem by using dynamic voltage restorer in series with distribution system. Dynamic voltage restorer is economical and effective solution for protecting sensitive loads from harmonics and sag. Control strategy is adopted with dynamic voltage restorer topology and the performance with the proposed controller is analyzed. Novelty. In this research work modelling, analysis and simulation of dynamic voltage restorer with proportional integral controller and dynamic voltage restorer with sliding-mode controller at optimal voltage is used to improve the dynamic voltage restorer performance by reducing total harmonic distortion. Results. The simulation is performed in MATLAB / Simulink software package and comparative analysis of dynamic voltage restorer with different controllers for distribution system is presented. The proposed scheme successfully reduced percentage total harmonics distortion and voltage sag using dynamic voltage restorer with sliding mode controller at optimal voltage which is found to be 0.38 %.
Analysis of the strategies for managing extended-range electric vehicle powertrain in the urban driving cycle
(Національний технічний університет "Харківський політехнічний інститут", 2022) Lasocki, Jakub; Krawczyk, Pawel; Kopczyński, Artur; Roszczyk, Pawel; Hajduga, Arkadiusz
An Extended-Range Electric Vehicle (EREV) is a type of electric vehicle that uses an additional internal combustion engine (ICE) to charge the battery in order to provide the vehicle with a greater range than in electric only mode. Purpose. Analysis and comparison of the performance of EREV powertrain managed according to three control strategies: pure electric mode, hybrid mode with ICE constantly working, and hybrid mode with ICE working only at high power demand. Methods. The tests were carried out using a laboratory test stand that represented the structure of EREV powertrain. Liquefied petroleum gas was used as a fuel to supply the ICE. The test conditions were defined by a special driving cycle simulating urban driving. Results. Time series plots of selected parameters of electric motor, electrochemical battery pack, range extender generator and active load system. Practical value. Among the considered control strategies of EREV powertrain, the energy balance of the electrochemical battery is negative for a purely electric mode, significantly positive for continuous range extenders (REXs) operation mode and moderately positive for the mode with REX activation only in dynamic states.
Power quality improvement using ultra capacitor based dynamic voltage restorer with real twisting sliding mode control
(Національний технічний університет "Харківський політехнічний інститут", 2022) Shah, Muhammad Shahzaib; Mahmood, Tahir; Ullah, Mian Farhan
Power quality is a major problem in today's power system, since it may have an impact on customers and utilities. Problem. Power quality is important issue of financial consequences for utilities, their consumers and load apparatus vendors. Voltage sag/swell are the most significant and usually occurring power quality issues in a secondary distribution system for sensitive loads. Goal. Dynamic voltage restorer is a fast, flexible, effective and dynamic custom power device can be used to compensate voltage sag/swell with integration of energy storage. Ultra capacitors have ideal properties of great power density and low energy density for elimination of voltage sag/swell. Their performance is mostly determined by the control strategy established for switching of voltage source converters. Originality. In this research, a strategy for the voltage source converter of dynamic voltage restorer based on the real twisting sliding mode control and ultra capacitor is developed to correct the fault that successfully eliminates the impacts of voltage sag/swell. Methodology. Ultra capacitor along with real twisting sliding mode control gives the more robustness and faster response, with also increasing the compensation time of the dynamic voltage restorer. Testing environment. To evaluate the performance of the proposed control approach, the MATLAB / Simulink SimPower System tool box is employed. Practical values. According to Simulation results clearly shows that the ultra capacitor along with real twisting sliding mode control effectively eliminate the voltage sag/swell in a very short time of 2 ms as compared to IEEE standards that is 20 ms, with less than 5 % total harmonic distortion for sensitive loads as per Information Technology Industry Council Curve and SEMI-F-47 Standards.
Comparative study between sliding mode control and the vector control of a brushless doubly fed reluctance generator based on wind energy conversion systems
(Національний технічний університет "Харківський політехнічний інститут", 2022) Oualah, Oussama; Kerdoun, Djallel; Boumassata, Abderraouf
Nowadays, global investment in renewable energy sources has been growing intensely. In particular, we mention here that wind source of energy has grown recently. Purpose. Comparative study between sliding mode control and vector control of a brushless doubly fed reluctance generator based on wind energy conversion systems. Methods. This paper deals with conceptual analysis and comparative study of two control techniques of a promising low-cost brushless doubly-fed reluctance generator for variable-speed wind turbine considering maximum power point tracking. This machine's growing interest because of the partially rated power electronics and the high reliability of the brushless design while offering performance competitive to its famous spring counterpart, the doubly-fed induction generator. We are particularly interested in comparing two kinds of control methods. We indicate here the direct vector control based on Proportional-Integral controller and sliding mode controller. Results. Simulation results show the optimized performances of the vector control strategy based on a sliding mode controller. We observe high performances in terms of response time and reference tracking without overshoots through the response characteristics. The decoupling, the stability, and the convergence towards the equilibrium are assured.
Method of adjustment of three circuit system of active shielding of magnetic field in multi-storey buildings from overhead power lines with wires triangular arrangement
(Національний технічний університет "Харківський політехнічний інститут", 2022) Kuznetsov, B. I.; Nikitina, T. B.; Bovdui, I. V.; Voloshko, O. V.; Kolomiets, V. V.; Kobylianskiy, B. B.
For the first time the method of adjustment of three circuit system of the active shielding of the magnetic field based on experimentally determined space-time characteristics to increase the shielding factor in a multi-storey building located near a singlecircuit overhead transmission lines with a wires triangular arrangement was developed. Methodology. When synthesizing the laboratory model of system of active shielding the coordinates of spatial arrangement and of three shielding coils, the currents in shielding coils and resulting magnetic flux density value in the shielding space were calculated. The synthesis is based on the multi-criteria game decision, in which the payoff vector is calculated on the basis on quasi-stationary approximation solutions of the Maxwell equations. The game decision is calculated based on the stochastic particles multi swarm optimization algorithms. Results. Computer simulation and experimental research of the space-time characteristics of laboratory model of three circuit system of active shielding of magnetic field, generated by overhead power lines with phase conductors triangle arrangements in multi-storey building are given. The possibility of initial magnetic flux density level reducing to the sanitary standards level is shown. Originality. For the first time the synthesis and adjustment of laboratory model of three circuit system of active shielding of magnetic field based on experimentally determined spacetime characteristics to increase the shielding factor in a multi-storey building located near a single-circuit overhead transmission lines with a wires triangular arrangement carried out. Practical value. Practical recommendations from the point of view of the implementation of developed method of adjustment of the three circuit system of the active shielding of the magnetic field based on experimentally determined space-time characteristics in a multi-storey building located near a single-circuit overhead transmission lines with a triangular arrangement of wires are given.