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PRZEGLĄD ELEKTROTECHNICZNY

Miesięcznik ISSN 0033-2097, e-ISSN 2449-9544 - rok powstania: 1919
Czasopismo Stowarzyszenia Elektryków Polskich (SEP)

Simulation of Eddy Current and Repulsive Force of Non-Ferrous Particles in Eddy Current Separator
(ang. Symulacja separatora cząstek nie-ferromagnetycznych wykorzystującego prądy wirowe)

DOI:10.15199/48.2019.06.09
Ahmed Nour El Islam AYAD Moulay LARAB Houari boudjella1 Farid Benhamida

Streszczenie
Eddy-current separation can be an effective technique for sorting non-ferrous metals from nonmetallic wastes. In this paper, we simulate the magnetic characteristics of rotational eddy current separator rounded by drum of permanents magnets in two dimensions, used to sort a mixture of non ferrous particles of different nature. The induced current and magnetic force of ejection in different kind and size of non-ferrous particles are simulated and computed by using the finite element method with Comsol Multiphysics software. The aim of this work is to show the magnetic performance of separator and induced current density in particles, the influence of the conductivity of each of non-ferrous particles on the eddy current and the repulsion force.
Słowa kluczowe: separatior magnetyczny, prądy wirowe, Comsol Multiphysics
Abstract
W artykule przedstawiono symulację pracy separatora magnetycznego z bębnem złożonym z magnesów i wykorzystującego prądy wirowe. Układ separatora i charakterystyki separowanych elementów modelowane są metodą elementu skończonego z wykorzystaniem oprogramowania Comsol Multiphysics.
Keywords: Eddy Current Separator, Magnetic Field, Repulsive Force, Non ferrous particles.
The waste quantities increase, according to time and especially with the technological development. The importance environmental pollution has been generated by electronics scrap refrigerator, television, end-of-life vehicles,… A waste contains different materials, for example: the plastic, aluminum, copper, steel, lead, permanent magnet, and residual toxic materials. Eddycurrent separation is a user-friendly and effective technique for the separation of nonferrous metals from wastes. Recovering of non ferrous particles from waste by the eddy current separation will bring renewable resources; this technique has been developed with time in many works [1, 2, 3]. The Lorentz force generated between nonferrous particles and the eddy current separator sort nonferrous from non-metals. The researchers develop several experimental works of separation by eddy-current technique for improving the performance of eddy-current separators and separation as: P. Rem, P. Z. Schlettt and M. lungu. For optimization of separation, for example, many factors are introduced: increasing the magnetic field intensity of permanent magnet, drum speed, size, shape, nature, the conductivity of the particle, the motion of particle and the trajectory [4, 5, 6]. There are several experimental works and analytical computations on permanent magnet eddy current separation but not much work on numerical simulation because there are two problems of particle translation and drum rotation and others problems. Our aim is to simulate rotational eddy current separator of alternating permanent magnets with the presence of non-ferrous particles of different size and nature (conductivities) in two dimensions with constant angular velocity. The aim of the present work is to compute the magnetic parameters of separator, the variation of repulsive force and eddy current density upon a mixture of conductive particles by the finite element method was presented in th [...]

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Bibliografia

[1] J. Ruan, Z. Xu, 2011, A new model of repulsive force in eddy current separation for recovering waste toner cartridges. Journal of Hazardous Materials 192 (2011) 307- 313
[2] Harini, N., Electrodynamic separation of metallic granules from mixed waste stream Master, .Science thesis The University of Utah 2010.
[3] Ayad Ahmed Nour El Islam, Ayad Abdelghani, Ramdani Youcef, 2016, Simulation of Eddy Current Separation of Gold Particles from Sands, International Journal of Engineering and Manufacturing(IJEM), Vol.6, No.5, pp.30-37, 2016.DOI: 10.5815/ijem.2016.05.04
[4] Huifen Zhang, Luzheng Chen, 2014, Eddy-current induced magnetic separation of nonferrous metals from solid wastes University of Science and Technology, Kunming 650093, China.
[5] P. C. Rem, E. M. Beunder, and A. J. van den Akker , 1998, Simulation of Eddy-Current separators’’ IEEE transaction on magnetics, vol. 34, no. 4, july 1998.
[6] M. Lungu, 2009, Separation of small nonferrous particles using a two successive steps eddy-current separator with permanent magnets. Int. J. Miner. Process. 93 (2009) 172-179
[7] Theory for the Magnetic Fields, No Currents InterfaceUser´s Guide magnetostatic equation AC/DC Module May Multiphysics software COMSOL 4.32012 www.comsol.com/support /releasenotes/4.2/acdc
[8] WU Caibin, Wang Quanjin, Xiang Sulin, Chen Peng, 2008, Valuable metal concentrate from waste printed circuits boards by eddy current separation. Environmental Science &Technology, Vol. 31, Issue 6,2008, pp. 12-18.
[9] Larson, Mats G., Bengzon, Fredrik, 2013, The Finite Element Method: Theory, Implementation, and Applications’’ Book 2013 xvii, 395 p hardcover 978-3-642-33286-9.
[10] Nagel J.R., Induced eddy currents in simple conductive geometries due to a time-varying magnetic field, IEEE Antennas and Propagation Magazine February ( 2018). 1045- 9243.
[11] James R. N,; An Analytic Model for Eddy Current Separation Department of Metallurgical Engineering University of Utah, Salt Lake City, Utah arXiv:1804.02435v1 physics.app-ph 6 Apr 2018

INNE PUBLIKACJE W TYM ZESZYCIE

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Zoltán NÉMETH Miklós KUCZMANN

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Krzysztof POPIOŁEK Tomasz DETKA Karol ŻEBROWSKI Konrad MAŁEK

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Application of a New Meta-heuristic Algorithm using Egyptian Vulture Optimization for Economic - DOI:10.15199/48.2019.06.11

Abdelkader SI TAYEB Hamid BOUZEBOUDJA

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Application of the UHF method for partial discharges measurement in high voltage cable lines - DOI:10.15199/48.2019.06.16

Michał KONARSKI Paweł WĘGIEREK

The growing requirements of customers in the scope of continuity of electricity supply in connection with the regulatory model, newly introduced by the Energy Regulatory Office, require distribution companies to constantly develop their grids to improve the reliability of power supply. The new model of regulation was introduced to reduce the value of reliability indicators in Poland, which, despite the significant increase in investment outlays in the distribution grid in recent years, still significantly deviate from the European average. For example, in 2016 in Poland System Average Interruption Duration Index (SAIDI) was 272 minutes/recipient, and System Average Interruption Frequency Index (SAIFI) was 3.46 interruptions/recipient. The average values of these indicators for the European Union were in the same year at the level of 170 minutes/recipient in the case of SAIDI (at the lowest value of approx. 20) and 1.75 interruptions /recipient in the case of the SAIFI indicator (at the lowest value of approx. 2) [1]. According to the quality regulation, distribution companies are required to reduce SAIDI and SAIFI indices by 50% by 2020, adopting the base year for 2015 [2]. Despite the fact that the qualitative regulatory model is in force for a few years, distribution companies are still far from reaching the assumed goals, which is mainly due to the sensitivity of the existing energy infrastructure to various types of failures. The Polish Power Grid is still mainly an overhead grid, which makes it particularly sensitive to damage caused by atmospheric phenomena. An example of the scale of the impact of weather phenomena on the reliability of power supply is the year 2017, when rapid storms combined with strong winds caused extensive damage to grids, which resulted in a significant increase in reliability indicators (for some Distribution System Operators even more than 2 times compared to 2016) [3]. The 2017 events showe więcej »

Comparison of Electric and Radiometric Methods for Liquid Dielectric Diagnostic - DOI:10.15199/48.2019.06.04

Michal KRBAL Jaroslav STEPANEK Ludek PELIKAN Jaroslava ORSAGOVA Iraida KOLCUNOVA

This paper is aimed at creating a comprehensive methodology for comparison the laboratory measured quality of liquid dielectrics by electrical and radiometric or photometric methods. Standard electric parameters diagnostic could be divided on partial discharge measurement according by IEC 60270; DC electric parameters (EN 60247); dissipation factor measurement (EN 61620) and for breakdown voltage measurement can be used the procedure according the standard EN 60156. Conversely radiometric measurement for determining liquid quality used only as an alternative method. An exception is the testing of plant oils intended for food industry. In this case, the oil quality, type of oil and the presence of other substances are determined by optical and radiometric methods. Liquid insulators used in power engineering and energetic are most often tested according to ISO 2049 and EN 60422. The ASTM scale according to standard ISO 2049 for the determination of color of insulating transformer oil or other petroleum product. However, very accurate measuring technology is nowadays offered by optical and light laboratories. The result may be spectral transmittance or absorption measurements in visible, IR and UV area of spectra. Especially the UV area has proved to be very sensitive to small differences in the change in the quality of liquid dielectrics. Also, luminescence measurement is a very interesting method for measuring the quality of liquid dielectrics, thermal degradation and the presence of additives and water content. Liquid dielectrics are used in the energetic and power engineering as insulating and heat transfer medium. Insulating oils are therefore an irreplaceable substance in many energetic systems and equipments such as transformers, some bushings, capacitors, oil cables or power switches and circuit breakers. The quality of liquid dielectrics greatly affects the reliability of the operation of these equipments. For this więcej »

Derivation of The Planar Square Coil Litz-Wire Winding Resistance for Sinusoidal Currents - DOI:10.15199/48.2019.06.19

Mateusz Czerwienko Andrzej Uramek Rafal P. Wojda

Introduction Demand of the wireless power transfer systems (WPT) for the high quality factor planar coils is significantly increasing. It can be seen that planar coils are utilized in systems like inductive heating, EV charging, robot charging, home appliances, medical appliances, and mobile device systems [20]- [36]. The addition of the ferrite introduces ferrite core losses and increases copper losses [19]. The air-core inductor with advantages of even magnetic field distribution and relatively lower costs could be utilized in such a systems [20]. Moreover in all of these systems, the low-loss planar inductors are required in order to increase the quality factor and to transfer energy with the highest possible efficiency. The WPT coils. operate at relatively low coupling factor (typical range 0.1 to 0.4), thus, there is a presence of high circulating currents that causes additional copper losses. These losses must be reduced in order to increase the WPT system efficiency thus high unloaded quality factor coils are required.Nomenclature γ = rs √ μσω - normalized radius of the strand; δ - skin depth; μ - free space magnetic permeability; σ - copper conductor conductivity; ω = 2πf - angular frequency of the conductor current; ESR - equivalent series resistnace; I - RMS value of the coil current; Ns - number of strands in the litz wire; Nt - number of the coil turns; Li, Lj - lengths of ith and jth coil sides; Pj - the power dissipated in the conductor j-th turn (one side of the coil); Rcoil - total resistance of the coil; Rdc, Rdcm - calculated and measured copper solid round wire DC resistance; Rmeas - measured AC winding resistance; Rprox, Rproxm - calculated and measured proximity effect winding resistance of the coil winding; Rskin - skin effect winding resistance of the litz wire; il(t) - sinusoidal winding conductor current; f, fcritical - operating frequency an więcej »

Design and Measurement of a Probe-Fed Open-Ended Rectangular Waveguide with Four-Stacked-Coupling-Aperture - DOI:10.15199/48.2019.06.13

Suthasinee LAMULTREE Rut PANTHASA Chuwong PHONGCHAROENPANICH

Point-to-point communication systems have promptly advanced and become one of the growing communication business over the late decades [1]-[2]. Particularly, point-topoint links between hosts and clients are required in numerous wireless communication systems over long distances, for examples, the microwave radio relay link, long length Wi-Fi, wireless WAN/LAN link, satellite communication, and home satellite television, etc. [2]-[4]. To increase the performance of the point-to-point communication desires a narrow-beam or pencil beam antenna with high gain [5], which is probably provided by a reflector antenna. To generate pencil beam for point-topoint communications, a symmetrical beam antenna is required for a primary feed [6], since the radiation pattern of the secondary antenna (reflector antenna) typically corresponds to that of the primary feed antenna [7]. However, it is not easy to obtain symmetrical radiation pattern because of the asymmetrical beamwidth between the yz- and xz-planes depending on the antenna structure [8]. The development of symmetrical beam antennas has been continuously researched and proceeded [9]-[12]. Among these symmetrical beam antenna designs, a tripleaperture waveguide antenna (TAWA) was lately introduced to be a primary feed antenna for reflector [11], because its structure is not complex. Nevertheless, the radiating section of TAWA is not small size. To further reduce the size of that radiating section, a probe-fed open-ended rectangular waveguide (OERW) with four-stacked-coupling-aperture (FSCA) antenna was preliminary studied for designing a symmetrical beam antenna in 2018 [12]. It was found that the effect of FSCA could transform the asymmetrical beam to be symmetry at -3 dB beamwidth. However, an equal beamwidth of both yz- and xz-planes at -10 dB could not accomplish yet. Therefore, this paper aims to continuously improve the FSCA for the better symmetrical beamwidth at -10 dB b więcej »

Effect of Nanocontacts on Transient States in Electrical Circuits - DOI:10.15199/48.2019.06.20

Maciej WAWRZYNIAK

Atomic-sized conductors have been intensively studied for more than ten years, resulting in the discovery of many interesting effects that do not occur in conductors larger in size [1]. A two-position switch [2] and a transistor [3] based on a single metal nanocontact placed on a substrate have been designed and verified to operate. Nanocontacts have been proposed to be used in sensors for the detection of lead and copper ions [4], terahertz signals [5] and linear shift [6]. Studies have also shown that nanocontacts can form between the contacts of a mechanical relay [7, 8] or a MEMS switch [9]. Of special importance is the observation of nanocontacts created in MEMS switches, used in radar components [10] and reduced power consumption systems [11]. Intensive research is conducted to improve the reliability, lifetime and switching rate of micromechanical switches. This requires an in-depth insight into the temperature effects [12], adhesion [13], creep [14] and wear [15]. The resistivity and hardness of the contact material as well as the surface topography affect the contact resistance [16]. The observed creation of nanocontacts makes this effect relevant for the analysis of the properties of MEMS switches and circuits including MEMS switches. Using switches in an electrical circuit results in the occurrence of transient states in the circuit when a switch is being opened or closed. A switch in a circuit is modeled as a two-state device characterized by two parameters, the closed-state resistance and the open-state resistance. However, if a nanocontact forms between its terminals in the opening or closing process, a switch cannot be modeled as a two-state element. This must be taken into consideration in the analysis of transient states in an electrical circuit including such a switch, as discussed in Ref. [17] for the final stage of the opening process. In this paper we present measurements and a theoretical analysis of więcej »

Effect of soil moisture on current-carrying capacity of low-voltage power cables - DOI:10.15199/48.2019.06.29

Stanislaw CZAPP Filip RATKOWSKI

Power cables are mainly installed in the ground, and parameters of the soil as well as additional cables equipment, e.g. a cable duct, significantly influence power cables current-carrying capacity [1-7]. This current-carrying capacity also depends on the position of buried power cables [8]. Moreover, sections of cables may be exposed to external sources of heat [9, 10], what should be taken into account during cables selection and it is very important in terms of reliability of supply [11]. Basic recommendations for calculation of power cables current-carrying capacity Iz are included in standards IEC 60287-1-1 [12] and IEC 60287-2-1 [13]. According to these standards, for AC power cables the capacity Iz can be calculated as follows: (1)   (1 ) (1 ) ( ) 0 5 ( ) 1 c 1 2 c 1 2 3 4 d 1 c 2 3 4 z R T n R T n R T T W , T n T T T I                           where: Iz - current-carrying capacity of a power cable, A,  - permissible temperature rise of the conductor above ambient temperature, K, Wd - dielectric losses per unit length per phase, W/m, T1 - thermal resistance per core between the conductor and sheath, (K.m)/W, T2 - thermal resistance between the sheath and armour, (K.m)/W, T3 - thermal resistance of external serving of the cable (e.g. PVC sheath), (K.m)/W, T4 - external thermal resistance of surrounding medium, e.g. soil, (K.m)/W, nc - number of conductors in a cable, -, R - AC current resistance of a conductor at its maximum operating temperature, /m, 1 - ratio of the total losses in metallic sheaths to the total conductor losses, -, 2 - ratio of the total losses in metallic armour to the total conductor losses, -. For popular low-voltage cab więcej »

Electrical tomography system for Innovative Imaging and Signal Analysis - DOI:10.15199/48.2019.06.24

Tomasz RYMARCZYK Paweł NITA Andres VEJAR Barbara STEFANIAK Jan Sikora

Introduction This article presents system architecture for innovative imaging and signal analysis in electrical tomography based on the construction of an electrical tomograph, measurement sensors and algorithms for data analysis [1- 3]. Diseases of the respiratory and circulatory systems are common today. The development of this type of diseases (both acute and chronic) is influenced by many factors, including stress and environmental pollution. Early diagnosis, as well as the possibility of continuous monitoring outside the infirmary, is unfortunately not possible. The main objective of the project is to create a tomographic system for imaging and monitoring region of interest (ROI) using the node potential map, along with the mechanism of interpretation of disease states. The system will consist of a device that records the electrical potential of cardiac function and lung ventilation [4-5]. The system will monitor the patients' condition and support the diagnostic process in such diseases as: - Chronic obstructive pulmonary disease (COPD) - Acute respiratory failure syndrome (ARDS) - Bronchospasm - Obstructive sleep apnea (OSA) - Pneumonia - Pulmonary hypertension - Pneumothorax - Aortic insufficiency - Cardiac Hemodynamics - Ischemic heart disease - Hypertension 24-hour monitoring of the vital functions of the patient is necessary for proper functioning. The future of medical diagnostics are long-term devices for patient monitoring - mobile devices that record a wide spectrum of diagnostics to detect pathological syndromes. The designed system will be able to monitor the following parameters: - Myocardial activity - Blood pressure - Blood flow - Impedance - Heart rate - Changes in pulmonary impedance - Lung capacity - ΔEELV (end-expiratory volume of lungs) - Bio-impedance - PEEP (positive end-expiratory pressure) - Patient position during the test - Relative electrical permittivity Architecture The więcej »

Enclosure-less six-phase induction motor - DOI:10.15199/48.2019.06.26

Maciej GWOZDZIEWICZ Piotr KISIELEWSKI

Laser cutting technology is being increasingly popular in electric machines manufacturing [8]. It enables to realize almost arbitrary project. The cost of laser cutting are going to even with cost of machining technology. Furthermore, AC electric machines can be built without enclosure. Of course, it reduces stiffness of the machine but simultaneously it decreases thermal resistance. FEM motor model In Ansys Maxwell software 2D FEM 6-phase 2-pole induction motor field-circuit model was built [1-2]. Rated motor parameters are given in Table I. Table 1. The parameters of the sensor parameter unit value Pn kW 2 Un V 200 Qs slots 24 Qr slots 19 Stator double layer winding consists of 24 coils made of round double enamelled copper wire with coil pitch ys=5/6. Rotor winding consists of quasi-trapezoidal copper bars. Each rotor bar includes 2 rectangular copper bars with wider one at the bar top. Rotor slot openings are quite wide to decrease rotor winding leakage reactance and to obtain high starting and maximum motor torques. FEM motor model is presented in Fig. 1. Ma więcej »

Incheon Airport Maglev Line - DOI:10.15199/48.2019.06.01

Doh-Young PARK Jacek F. GIERAS

Korea Urban Maglev Program started in December 2006 at Korea Institute of Machinery and Materials (KIMM) in Daejeon. The construction of passenger carrying service of 6.1-km, low-speed Incheon Airport Maglev Line (IAML) started on February 3, 2016. It was preceded by complete and thorough system interface tests, part of which were required by the regulations. The IAML is a completely passive system with attraction electromagnets and primary units of the linear induction motor (LIM) installed in vehicles, while reaction rails for electromagnets and LIMs are installed in the track [1]. The IAML connects Incheon International Airport Transportation Center (IIATC) with Yongyu station in Yeongjong Island. There are 6 stations: (1) IIATC, (2) Long- Term Parking, (3) Administration Complex, (4) International Business Center, (5) Water Park, (6) Yongyu Station. Fig. 1. Route map (red line) of the IAML. Construction The double-track elevated guideways of the IAML are installed on concrete pillars. The highest elevation is 24.5 m, the maximum gradient is 45 ‰ and the minimum curve radius 50 m. There is a maintenance depot and control center in the vicinity of Yongyu Station. The route map is shown in Fig. 1. The trainset on elevated guideway is shown in Fig. 2. The Incheon Airport Transportation Center Stati więcej »

Mathematical model of XLPE insulated cable power line with underground installation - DOI:10.15199/48.2019.06.14

Oleg KROPOTIN Vsevolod TKACHENKO Aleksandr SHEPELEV Elena PETROVA Vladimir GORYUNOV Aleksandr BIGUN

Underground medium-voltage cable lines are used for distribution and transmission of electric energy. Single-core cables with cross-linked polyethylene insulation are widely used. Power consumption due to urban and industrial park development increases. Therefore, the issue of analyzing the capacity of cable lines becomes urgent. The capacity of electric power lines depends on the conductor temperature [1-4]. The temperature is significantly affected by the process of cable heat dissipation into the environment. Specific nature of thermal processes plays an important role in assessing the rational use of cable systems [5-7]. Various aspects in the research of power cables with allowance for thermal processes are presented in [8-17]. A popular approach is to determine the temperature of cable elements using the numerical method of the finite elements. However, significant computational resources that are required, the complexity of the initial data preparation, and analysis of the calculation results in some cases limit the application of this approach. Below it is proposed to determine the temperature of the cable based on the thermal equivalent circuit. The ambient temperature and losses in the cable elements, being taken into account, are considered to be the advantages of this model, as well as the ability to determine the effect of adjoining cables on the processes. Mathematical model of cable power line with crosslinked polyethylene insulation The mathematical model of the cable line with crosslinked polyethylene insulation is formed for the cable crosssection shown in Fig. 1, where r0 - rn are outer radii of cable layers, Θi is the temperature of the medial line of the i-th cable layer, that is the temperature of the i-th layer on the radius rmedi=ri+0.5·(ri+1 - ri), С. For a computational model of the single-core cable, each layer (Fig.2) of the cable cross-section (r1-rn) is represented as więcej »

Micro-bending sensor made from polydimethylsiloxane - DOI:10.15199/48.2019.06.02

Martin NOVAK Jan JARGUS Jan NEDOMA Vladimir VASINEK Radek MARTINEK Martin STOLARIK

Polydimethylsiloxane (PDMS) is a polymeric material on the basis of silicone, which is used in many scientific fields for various applications. One of the key characteristics is the excellent heat resistance of the material, under long term heat exposure PDMS resists temperatures of 200 °C and for short term exposure temperatures up to 350 °C. This is why it is very often used in electronics for pouring plates of wide connectors, transformers, power sources and so on. The authors of publication [1] concentrate on one concrete type of polydimethylsiloxane identified as Sylgard 184 and check its mechanical characteristics at various hardening temperatures (25 - 200 °C). The results show that the hardening temperature can change certain mechanical characteristics of PDMS. Samples prepared at a hardening temperature of 25 °C showed a hardness value of 43.8 Shore A, whereas samples prepared at a temperature of 200 °C showed a hardness value of 54 Shore A. In the construction of sensors (particularly pressure sensors) this information is very important because the hardness of the material undoubtedly affects the resulting behaviour of the sensor. Publication [2] describes a magnetic pole sensor which is constructed from two types of PDMS and a multimodal optical fibre with iron nano-particles. The cover of the sensor is formed by hard polydimethylsiloxane and the internal part of the sensor is filled with a soft silicon gel based on PDMS, so that it is possible using a magnetic field to deflect the first optical fibre with the iron nano-particles. The deviation of the optical fibre has an output of lowering the optical performance. A sensor set up like this can detect a magnetic field up to 0.3 T. A slightly altered sensor can also for instance detect vibrations up to 100 Hz, as is shown in publication [3]. A simple form of pressure sensor made from PDMS is shown in publication [4]. When manufacturing the sensor it is very impo więcej »

Minimization of Objective Function in Electrical Impedance Tomography by Topological Derivative - DOI:10.15199/48.2019.06.25

Tomasz RYMARCZYK Katarzyna SZULC

Electrical impedance tomography (EIT) is a non-invasive problem of image reconstruction in which the distribution of conductivity in an object domain can be reconstructed using external voltage measurements. EIT is an imaging technique with existing and potential uses in engineering and medical problems. In this method, electric currents are injected into a conductive object through electrodes placed on its surface, and the resulting electrical potential on the electrodes is determined. In the opposite case, the objective function is minimized in an iterative procedure, using the measured and modeled data, the internal conductivity profile is calculated. Electric tomography can be used in industrial, medical and geophysical applications. Recently, there has been a dramatic increase in the field of chest imaging, with an emphasis on lung ventilation and heart rhythm monitoring. The finite element method was applied to domain modeling, and topological algorithms were used to solve the inverse problem [21]. The problem of topology optimization applied in the EIT is to find the conductivity distribution of the object, which minimizes the difference between electrical potentials obtained from measurements of electrodes at the boundary of the object and numerically simulated electrical potentials [3,4,8,14-16]. Topological Derivative The optimization problem is usually defined as the minimization of a given activity [2,6,9-11,13,22]. Shape derivatives and topological derivatives have been included in the level determination methods to investigate problems related to shape optimization [17, 18]. The basic method of shape optimization is a topological derivative evaluated for a given functional shape defined in the geometric field and dependent on the classical solution of the elliptical problem of the limit of value. The topological derivative is defined as the first term of asymptotic expansi więcej »

Modeling and Adaptive Power Control-Designed based on Tip Speed Ratio method for Wind Turbines - DOI:10.15199/48.2019.06.08

Youcef SAIDI Abdelkader MEZOUAR Yahia MILOUD Maamar YAHIAOUI Mohammed Amine BENMAHDJOUB

In the last decades, the WE (wind energy) is becoming one of the most promising renewable energy sources due to the experienced progress. WE is playing a key role in the effort to help and satisfy global energy demand, offering the greatest opportunity to unlock a new era of environmental protection with share of renewable energy sources in the world energy mix [1-3]. In this way, it can help to solve the world energy crises and global warming problem. Therefore, WT-s must operate in such a way as to optimize the kinetic energy of the wind for optimal electrical energy [4, 5]. Although WT-s have a lower installation cost compared to photovoltaic, the overall system cost can be further reduced using high-efficiency power converters, controlled to obtain the optimum power according to current atmospheric conditions [5, 6]. Aerodynamic wind systems based on variable speed turbine have been used for many reasons. Among the WECS currently available, variable-speed based on aerodynamic wind systems are steadily increasing their market share, since changes in wind speed are followed by shaft speed control, which allows the turbine to function at its at maximum capacity regardless of wind speeds [7]. One of the most major problems in aerodynamic wind systems is capturing as much aerodynamic wind power as possible in the shortest possible time, which can be achieved through different MPC approaches [8-10]. In order to determine the optimal operating situation of the WT-s, it is essential to include a MPPT (Maximum Power Point Tracking) algorithm in the system. Many papers for MPPT technique have been presented in the literature, with different control schemes of WT-s to extract a maximum of power from wind speed variable, such as reference [11], which provided an analytical and critical study of several papers published in this area including [12, 13]. To maximize and improve the quality and the quantity of energy in wind farms con więcej »

Nonlinear system identification of a MIMO quadruple tanks system using NARX model - DOI:10.15199/48.2019.06.12

Ícaro ARAÚJO Gabriel CAVALCANTE Yan LÚCIO Fábio ARAÚJO

System identification is a knowledge area with the main objective of developing methods and techniques to find accurate and reliable mathematical representations for dynamic systems from observed data and available knowledge [1, 2]. A way to build these models is using information from collected system data to build ratios between inputs and outputs from the process, thus describing their dynamics. This method is called black-box identification since no information about internal details is used. Some real applications, especially industrial applications, have multiple-inputs and multiple-outputs (MIMO) systems. Such systems present some difficulties in obtaining mathematical models by physical laws (white-box modelling) or even by black-box methods to represent their dynamic behaviors. Therefore, linear models are used to represent the dynamics of such MIMO systems but they present lower quality than non-linear models. In black-box system identification, the representation of the polynomial nonlinear autoregressive moving average with exogenous input (NARMAX), proposed by [3], has a great performance in its ability to represent a nonlinear input-output relationship. In cases where the deterministic input-output relationship is the focus, a nonlinear autoregressive with exogenous input (NARX) model can be employed, using a simplification of the disturbance model [4]. Other researchers demonstrate these capabilities improved with applied techniques of structure selection and parameter estimation, enabling to find models with better representation and most robust performance, as explored in [5, 6]. Some papers propose the use of Artificial Neural Networks models [7, 8] or more elaborate methods [9, 10] for the task of identifying MIMO systems. However, NARX model-based identification methods, although generating less accurate models than the previously mentioned methods, have the advantage of generating simpler and easier więcej »

Polynomial Approximation of the Maximum Dynamic Error Generated by Measurement Systems - DOI:10.15199/48.2019.06.22

Krzysztof TOMCZYK

Introduction Determination of maximum dynamic error [1] first requires the synthesis of a mathematical model for the considered measurement system. This model must be developed in such a way that it allows the associated impulse response to be calculated. This condition is met for models based on differential equations, transfer functions, complex frequency responses or state equations. Mathematical model of most measurement systems (e.g. sensors) have a strictly defined structure and order. The parameters of this structure are determined by parametric identification [2-5] in accordance with the guidelines included in the dedicated standard [6]. This identification consists of two main stages, the first of which involves a practical experiment to determine the measurement of time or the frequency responses of the system. The second stage involves the approximation of this measurement by means of the extended least squares method, and aims to determine the values of particular model parameters [7-11]. The calculations at this stage can be conveniently performed using mathematical software (MATLAB, MathCAD, etc.), due to the necessity of carrying out advanced computations involving vector and matrix calculus. In this method, many procedures are used that are described both in international standards and in the scientific literature [10-13]. These procedures are used in routine calibration tests of measurement systems, which are carried out both in companies and in scientific centres. When a mathematical model of the system has been developed, an appropriate mathematical procedure should be applied to determine the maximum dynamic error that can be generated by this system. The shape of the input signal (both the number and the switching times) is also determined, as is the constraint on its magnitude [14]. In response to this signal, the maximum value of the dynamic error is obtained; any other real signal with switching t więcej »

Power interface efficiency evaluation for photovoltaic system used in hydrogen production - DOI:10.15199/48.2019.06.15

Zoubir BELGROUN Mustapha HATTI Salah HANINI

Magneto Caloric Effect (MCE) consists to liquefying hydrogen to optimize its storage,the hydrogen producedtoday by means of solar energy that become an important source of power generation. However, the main problem in the proper exploitation remain how it is stored; one of the best storage methods is the liquefied hydrogen system. The hydrogen generation system simply consists of a PV module that connected to a hydrogen cell by DC converter that means the best optimization of hydrogen system is optimization of the photovoltaic (PV) system. A dozen of studies have been conducted on the use storage in renewable energy. Where Khalid et al. [1] suggested a renewable-based energy system for a house using hydrogen as a storage medium. Kalinciet al. [2] studied a standalone energy system for an island in Turkey using hydrogen as a storage option. ezmalinovic et al. [3] discussed the role of PEM fuel cells in PV based systems for remote base stations. They considered various scenarios such as PV/battery, PV/battery/diesel, generator and PV/battery/PEM fuel cell [4]. Electrolyzer cell technology provides a sustainable solution for renewable energy storage and hydrogen production. Among all types of electrolyzer cell systems, PEMFC is providing a promising solution for hydrogen and oxygen production and receiving more and more attention due to their higher energy efficiency/density, faster charging/discharging, and a more compact design [5]. Solar power is the conversion of sunlight into electricity, either directly using photovoltaic (PV), or indirectly using concentrated solar power. Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaic cells convert light into an electric current using the photovoltaic effect [6]. PV solar systems exist in many different configurations with regard to their relationship to inverter systems, external grids, f więcej »

Predykcyjne sterowanie równoległym filtrem aktywnym ze sprzężeniem od prądu zasilającego - DOI:10.15199/48.2019.06.23

Agata BIELECKA Daniel WOJCIECHOWSKI

Wraz z rozwojem energoelektroniki można zauważyć wzrost liczby i mocy sumarycznej instalowanych odbiorników nieliniowych, w tym układów przemysłowych takich jak: prostowniki trójfazowe [1], napędy przekształtnikowe, czy też piece łukowe, a także odbiorników konsumenckich: zasilaczy impulsowych, oświetlenia energooszczędnego. Powoduje to wzrost odkształcenia prądów zasilających, co wraz z mocą bierną skutkuje zwiększeniem strat w elementach przesyłowych, np. transformatorach energetycznych [2]. Obecność wyższych harmonicznych w prądach zasilających prowadzi do odkształcenia napięć zasilających, które wpływając na instalowane odbiory, mogą powodować ich nieprawidłową pracę [3]. Konsekwencji powyższych zjawisk jest znacznie więcej i całościowo są ujęte w problematyce jakości energii elektrycznej. Skuteczne narzędzie do poprawy jakości energii elektrycznej stanowią równoległe energetyczne filtry aktywne (EFA). Zapewniają one kompensację harmonicznych prądu, mocy biernej oraz asymetrii, poprawiając w ten sposób przebieg napięcia w sieci zasilającej [4]-[7]. Dzięki temu stają się coraz bardziej popularne, a wiele ich topologii oraz strategii sterowania można znaleźć w licznych publikacjach [8]. Można wyróżnić dwie główne strategie sterowania równoległymi EFA ze względu na miejsce pomiaru prądu, na podstawie którego wyznaczany jest zadany prąd kompensacyjny. Pierwsza to sterowanie w układzie otwartym (ang. Open-loop), która oparta jest na pomiarze prądu odbioru. Druga natomiast, to sterowanie w układzie zamkniętym (ang. Closed-loop), w której mierzony jest prąd sieci zasilającej [9]. Sterowanie w układzie otwartym jest popularnym rozwiązaniem i powszechnie spotykanym w przemyśle. Charakteryzuje go stabilność (wynikająca ze struktury układu) i relatywnie krótki czas przejściowy po zmianie prądu odbioru, znacznie krótszy niż w przypadku układu zamkniętego. Ponadto strategia ta nie ma wysokich wymagań obliczeniowych. Układy ster więcej »

Selfoptimization local electric systems modes with renewable energy sources - DOI:10.15199/48.2019.06.06

Petro LEZHNIUK Serhii KRAVCHUK Andriy POLISHCHUK

Electric grids were functionally designed to transport and distribute electricity produced centrally at large power plants. With the development of non-traditional and renewable energy sources (RES), they acquire the features of a local electric system (LES). In this connection, new tasks arise: harmonization of load schedules of consumers and generation of RES with consideration of their dependence on meteorological parameters of the environment, optimal control of power flows in order to reduce the losses of electricity and improve its quality, ensuring the balance power reliability of the formed LES centralized and local generation, etc. Naturally, it is advisable to solve these problems with the use of modern Smart Grid technologies [1-3]. Among the tasks to be solved for switching to the electrical grids (EG) based on the concept of the Smart Grid, there are, among other things, tasks whose solution is intended to improve the power flow control system [4, 5]. To do this, it is necessary to ensure the technical condition and regulatory capabilities of the relevant equipment. This, first and foremost, concerns the actual renewable energy sources (RES) - wind and solar power stations (WEP and PV), small hydroelectric power plants (SHPP), cogeneration and biogas plants (CGU and BGU) [4, 5]. This also applies to transformers and autotransformers with tap regulators, for which modern operational diagnostic systems should be created, as well as improved conditions for their operation in order to optimally utilize their load capacity to control power surges between higher and lower voltage grids [6] . At the same time it is necessary to improve the activeadaptive automatic control system (ACS) with power and voltage flows in electric grids of power systems, which allow to minimize power losses in them taking into account the technical state of electrical equipment of RES and the control effect of transformers with voltage and więcej »

Simulation Platform for Analyzing Environmental Effects in Multi-Wavelength Transmission Systems in Matlab Simulink - DOI:10.15199/48.2019.06.03

Rastislav RÓKA Martin MOKRÁŇ

One of methods that can increase a transmission capacity of the optical fiber is the Wavelength Division Multiplexing (WDM). Various forms of wavelength multiplexing techniques are considered for utilization in future metro-access networks with a combination of different network topologies [1]-[5]. Moreover, advanced modulation formats are investigated for utilization in nextgeneration passive optical networks with the WDM implementation [6]. This work aims to investigate environmental effects in multi-wavelength transmission systems and their specific influences on transmitted information signals [7]-[11]. With regard of the utilized frequency spectrum, two WDM forms can be under consideration [12]-[13]. One of advantages for Coarse WDM systems [14] is a cheaper implementation, since there is a larger channel spacing that allows using of simpler components like lasers and optical filters. Their main disadvantages are a smaller maximum count of transmitted channels and a complicated amplification, since a wider spectral transmission band is used and optical amplifiers are usually designed for a narrower spectrum. One of main advantages for Dense WDM systems [15] is a larger count of transmitted channels (up to hundreds) and a simpler possibility of optical amplification e.g. using EDFA amplifiers. For our investigation, it is crucial to prepare and create a reliable simulation platform that can be used for analyzing environmental effects at multi-wavelength signal transmission in optical systems. Therefore, the main part of this paper is intended for detailed description of particular block functionalities in the specific simulation platform for WDM systems and, subsequently, for analysis of environmental effects in CWDM and DWDM transmission systems. Principles of WDM Systems and Their Available Frequency Spectrum WDM systems allow transmitting of multiple user data channels through the one optical transmission path. T więcej »

Spotkanie z zespołem redakcyjnym Web od Science i warsztaty dla wydawców polskich czasopism naukowych

Na spotkaniu tym zostałem zaproszony do zaprezentowania naszych doświadczeń z WoS - poniżej treść prezentcji. ST I represent the journal Przeglad Elektrotechniczny and SIGMA-NOT the largest Company editing technical journals. Przeglad Elektrotechniczny is a journal with great tradition - it is one of the oldest technical journals in Poland., the oldest journal devoted to EE in Europe - this year we have 100 years anniversary. I think that I was invited to this presentation because we are experienced in evaluation process of Web of Science - we were two times accepted and one time dropped from this base. I am an Editor-in-chief of this journal since 17 years. When I started in 2002 on this function the journal had the difficult period - high reputtion lost, submission of the papers was small, we published not more than a few papers a month, subscription decreased dramatically from thousands to hundreds copies. Thus Przeglad was endangered by liquidation and I obtained only one year to introduce repair process. We introduced following four main steps: - I think that it is always most important step - we attempted to recover and collect the best as possible authors and reviewers. Due to my friendly relation with many prominent professors I was able forced them to publish papers in our journal and they could not refuse. And really when other authors observed that in our journal are published interesting and significant papers and in journal are publishing reputable authors in a short time the submi więcej »

Start-up of large power electric motors with high load torque - DOI:10.15199/48.2019.06.27

Jan ZAWILAK Maciej GWOŹDZIEWICZ

The copper ore extracted from mines has a copper content of approx. 0.96 - 2.5%. As a result of many complicated and energy-consuming technological processes (sifting, crushing, grinding, flotation, compaction and drying), a concentrate with a copper content of. about 25% is obtained. The concentrate is delivered to a smelter, where it is subjected to the processes of melting, converting and refining. The final products include, inter alia, electrorefined cathodes with a 99.99% copper content. In addition, other metal elements (gold, silver, molybdenum) are recovered from ore deposits [2, 3, 5]. In the technological processes of copper ore enrichment, approximately 660 GWh of electricity is consumed annually, while the demand for this energy by electric drive systems amounts to about 95%. Electricity charges constitute approx. 30% of the value of production costs. This is why it is important to look for innovative technical solutions which aim to save electricity. High-power, continuous-operation electric drive systems, in the case of which even a small increase in efficiency results in a large reduction in operating costs, are of particular importance. Ore grinding systems belong to such drives. They use more than half of the total electricity consumed by processing plants. The drive systems of mills are characterized by very high inertia and difficult start-up (high resistive torque), especially when the mill is filled with muck. SAS type motors (Asynchronous Motor Synchronized, in Polish: Silnik Asynchroniczny Synchronizowany, with a rotor band winding and slip rings) to which a starting device (a threephase resistor or an electromagnetic device (the so-called eddy curren więcej »

Steady State Stability Limit Assessment when Wind Turbine Penetrated to the Systems using REI Approach - DOI:10.15199/48.2019.06.10

Agus SISWANTO Ansar SUYUTI Indar CHAERAH GUNADIN Sri MAWAR SAID

In the past decade, the increase in electricity loads has risen sharply, so that the extensive use of fossil fuel power plants produces a lot of gas so that air pollution, global warming, and climate change become problems in various countries. For this reason researchers are developing renewable energy sources (RES) to save and reduce the effects of global warming to reduce fossil fuels by 30% of the total energy generation. From various RES sources, various regions that have the potential of wind turbines have been developed. The South Sulawesi electricity system has installed wind turbines in the Sidrap area of 75MW which are connected to a 150kV transmission line. Wind turbines are the most environmentally friendly type of generator and the most promising resource as a source of energy, economically this plant is very profitable because it does not require production costs, but stability can potentially bring negative impact to the electricity system. The penetration of intermittent power output from wind turbines due to uncertainty in wind speed which has a negative impact on the stability of the electric power system in South Sulawesi [1,2] Installing the wind turbine on a 150kV transmission line on the South Sulawesi system can have an increase in stability when the power supply does not fluctuate, but this can result in a decrease in system stability when the fluctuations in changes in weather conditions and wind speed. The penetration of wind turbine needs to be considered because it can reduce the critical clearing angle (CCA) when the interference, rotor angle stability, distance, frequency, control between the generator occurs and the control mode of the system is briefly interrupted [3-5] In general it has been divided into two categories the WTG have been they are, fixed speed and variable speed. The fixed speed of WTG generally uses a squirrel cage generator (SCIG) to convert mechanical energy from a wind t więcej »

Synchronization of the iterative process for voltage harmonic mitigation - DOI:10.15199/48.2019.06.18

Kazimierz MIKOŁAJUK Zbigniew STAROSZCZYK Andrzej TOBOŁA

The control of active power filters can be divided into three groups: control based on instantaneous power, control based on current, and control based on voltage measurements. The shunt active filters based on voltage detection at the points of compensator installation seem to be more flexible then current-controlled compensators [1]. The power necessary for active filtering can be maintained at a very low level with an accurate design of control and of the passive components. For example, the power usage of the active filter can be about 1.5% of the nominal value. The voltage-controlled method, which does not require the knowledge of the load current, determines the reference signal basing only on voltage waveform observations at the point of filter installation (PCC) and then injects the proper compensating current. Such filters should be installed in the power system rather not by consumers, but by the grid operator. The voltage-controlled method proposed in [2] forms a feedback control loop. The filter detects voltage harmonics at the point of filter installation, and then injects a compensating current. The active filter forms a short-cut for all harmonic except of the fundamental frequency. For fundamental harmonics it forms the open circuit. This method is fast as it is based on instantaneous voltage and current observations. However time delays (phase shifts) in active controller deteriorate harmonics damping and can lead to filter instability. The modifications presented in [3] are based on the assumption that all harmonics of the compensator current should be orthogonal to voltage harmonics (phase shift of π/2) as the grid impedance has dominating inductive character. More information on system parameters can be obtained from the experiments proposed in [4,5]. The vector control is the another common approach to harmonics compensation. With the synchronous reference frame implemented in grid-tie converters więcej »

The Use of Grey Wolf Optimizer (GWO) for Solving the Economic Dispatch Problems based on Renewable Energy in Algeria A case study of "Naama Site" - DOI:10.15199/48.2019.06.07

Mokhtar MAAMRI Hamid BOUZEBOUDJA Mohammed Nasser TANDJAOUI

Energy has served as an important source of economy for many decades. What is meant by energy? Energy is for instance, natural gas, diesel, coal, and electricity, this energy is needed to run vehicles, devices, machines: to fertilize and irrigate lands, harvest crops, to light up and heat apartments, buildings and factories. Since the use of energy is involved in each step of previous fields, surely people’s welfare is likely to go down in the lack of energy. [1]. Fossil fuels like coal, oil and natural gas are currently the world’s primary energy sources. The heavy dependence on the fossil fuel reduced the natural reserve of it. To take care of the balance and limited life of conventional sources which creates danger on the environment, research on alternative sources of energy is carried out [2]. In current decades, renewable energy resources have received considerable attention in both grid independent and on-grid applications. The benefits associated with renewable resources include: reducing environmental pollution, endlessness, improved power quality, and reliability, and saving power for the next generations [3, 4]. Engineers and scientists are increasingly trying to find and use alternative energy sources. The three most widely used renewable energy sources are hydro, wind and photovoltaic (PV) [5]. Fig.1. Most common forms of renewable energy A well-engineered renewable energy system can reduce costing of energy, consequently improving lifestyle [6]. Hybrid power system uses more than one type of generator, usually, a conventional generator powered by diesel, and a renewable energy source such as wind energy and photovoltaic (PV). Various “hybrid" system of renewable energy sources and diesel generators are currently being developed and marketed [7]. The present paper comprehensively reviews the hybridization of wind, PV energy and gas turbine, installed in Naama-Algeria. This study will analyze więcej »

Wspomnienia o profesorze Krystynie Pawluku (1926 - 2018)

Drogę życiową z ZSRR do Polski Krystyn Pawluk pokonywał wspólnie z rodzicami oraz z bratem Lesławem - - w wojennych i trudnych -- powojennych warunkach. Wiodła ona z miejsca zamieszkania Mielnicy Podolskiej, leżącej w województwie tarnopolskim -- poprzez Lwów do Krakowa. Obaj bracia Pawlukowie zdobyli wykształcenie średnie w Krakowie (uczyli się w Liceum im. Witkowskiego). Krystyn dysponując wrodzonymi zdolnościami matematycznymi i znając dobrze fizykę, którą poznał na tajnych kompletach we Lwowie - nie miał wahań przy wyborze kierunku dalszej nauki. Wybrał dobrze znaną przed wojną w Polsce uczelnię AGH (Wydział Elektromechaniczny). Dyplom magistra inżyniera elektromechanika hutniczego uzyskał w listopadzie 1951 r. Pracę dyplomową na temat modelowania matematycznego wykonał pod opieką naukową profesora Władysława Kołka -- będącego "repatriantem ze Lwowa". Po uzyskaniu dyplomu Krystyn odbył roczny staż zawodowy w Krakowskiej Fabryce Kabli. Dalsze kontakty zawodowe z prof. Władysławem Kołkiem, z biegiem czasu zmieniły charakter i stały się również kontaktami towarzyskimi. Częstymi tematami rozmów były metody analizy i syntezy pól elektromagnetycznych. W dużym stopniu rozmowy z Profesorem zbliżyły Krystyna do Profesora - jako człowieka o szerokiej, wszechstronnej wiedzy, życzliwego ludziom. Szczególnie częste spotkania miały miejsce w latach 1953 - 1957, gdy Profesor organizował w AGH Katedrę Maszyn i Pomiarów Elektrycznych. W tej to jednostce naukowej Krystyn pracował już, jako nauczyciel akademicki. Był również członkiem sześcioosobowego, nieformalnego - lecz wyróżniającego się poziomem naukowym zespołu, zwanego "Krakowską Szkołą Maszyn Elektrycznych". Wszyscy członkowie tej Szkoły w dalszych latach - w różnych jednakże więcej »

Zastosowanie metody ANP do walidacji koncepcji instalacji elektrycznych w pojazdach samochodowych - DOI:10.15199/48.2019.06.28

Bartłomiej TWOREK

Procesy optymalizacji topologii instalacji elektrycznej spowodowały znaczny spadek masy, jednak masa wiązek elektrycznych oraz złącz wynosi wciąż ok. 60 kg w przypadku współczesnych pojazdów klasy wyższej (np. Audi A8 D5). Przeciętna łączna długość wiązek elektrycznych wynosi około 6000 - 7000m w zależności od wariantów wyposażenia samochodu. Złożone wiązki elektryczne jak i elementy mocujące zabierają cenną przestrzeń użytkową co jest niekorzystne, tym bardziej w przypadku pojazdów wyposażonych w liczne systemy wspomagające jazdę [1]. Rozwój instalacji elektrycznych w pojazdach umożliwił lepsze dostosowanie wiązek do obsługi wielu odbiorników energii, jednak pojazdy elektryczne i w przyszłości autonomiczne wymagają zastosowania podsieci 48V w celu redukcji strat mocy i ograniczenia prądu nominalnego [2]. Aby sprostać tym potrzebom należy zastosować instalację elektryczną, która pozwoli w efektywny sposób dostarczyć energię do odbiorników dużej mocy (np. elektryczne turbosprężarki, układy ogrzewania w pojazdach elektrycznych) [3]. Autor artykułu opracował koncepcję instalacji elektrycznej, która znajduje zastosowanie w pojazdach klasy wyższej [11]. Koncepcja ta obejmuje podsystem 48V i integruje Sterownik Centralnej Dystrybucji Energii, który odpowiada za zarządzanie przepływem energii w systemie elektrycznym pojazdu. Dzięki wykorzystaniu przetwornicy DC/DC możliwa jest integracja dwóch podsystemów elektrycznych o różnych poziomach napięć. Sterownik Centralnej Dystrybucji Energii posiada funkcje aktywnego zabezpieczenia obwodów przed przeciążeniami i przepięciami poprzez zastosowanie układów eFuse. W artykule zostanie zaproponowana metoda wyboru wariantu instalacji elektrycznej dla pojazdów samochodowych w oparciu o metodę wielokryterialnego rozwiązywania problemów decyzyjnych ANP. Dane odnośnie budowy instalacji elektrycznych pojazdów pozyskano z serwisu A2MAC1 [13] który zajmuje się badaniem rozwiązań technicznych w więcej »

Zastosowanie zmodyfikowanych estymatorów strumienia wirnika do kompensacji skutków zwarć zwojowych stojana silnika indukcyjnego - DOI:10.15199/48.2019.06.17

Mateusz DYBKOWSKI Szymon Antoni BEDNARZ

Silnik indukcyjne (SI) są jednymi z najpopularniejszych maszyn elektrycznych stosowanych się w układach napędowych. Maszyny te charakteryzują się relatywnie niskim kosztem zakupu oraz dużą niezawodnością. Do regulacji SI można zastosować różnego rodzaju metody, które generalnie można podzielić na metody skalarne i wektorowe [1], [2]. Druga grupa metod charakteryzuje się możliwością bardzo dokładnej regulacji momentu i/lub prędkości maszyny, dlatego jest coraz częściej stosowana w praktycznych rozwiązaniach. Układy te należy uzupełnić o estymatory zmiennych stanu - estymatory strumienia wirnika lub stojana [3], [4]. Jednymi z takich układów są tak zwane symulatory zmiennych stanu - modele opisujące w sposób bezpośredni model matematyczny silnika indukcyjnego, które charakteryzują się nieskomplikowaną strukturą [3], [4]. Pomimo wielu zalet, SI nie są całkowicie niezawodne. W trakcie pracy maszyny może dojść do uszkodzenia jej elementów [5], [6], [7], [8]. W ogólnym przypadku można wyróżnić uszkodzenia mechaniczne oraz elektryczne. Najczęściej występującymi uszkodzeniami elektrycznymi są te związane z uzwojeniem stojana [8]. Uszkodzenie to związane jest z degradacją izolacji, które następnie objawia się zwarciami. Uszkodzenia uzwojenia stojana mają negatywny wpływ na pracę maszyny elektrycznej [5], [6]. Są to uszkodzenia, które, w porównaniu do uszkodzeń uzwojenia wirnika postępują stosunkowo szybko i w skrajnym wypadku mogą doprowadzić do całkowitego uszkodzenia silnika lub nawet całego napędu elektrycznego [5], [6]. Jednakże są to uszkodzenia możliwe do wykrycia, a prędkość ich rozprzestrzeniania zależna jest miedzy innymi od typu maszyny [5]. Pierwszym stadium tego typu uszkodzenia są zwarcia między zwojowe, dlatego większość badań skupia się właśnie na ich diagnostyce [6], [8]. Niestety każda zmiana (uszkodzenie) w uzwojeniu stojana pociąga za sobą zmiany w parametrach SI [9], [10], [11]. W przypadku, gdy silnik elektr więcej »

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Simulation of Eddy Current and Repulsive Force of Non-Ferrous Particles in Eddy Current Separator
(ang. Symulacja separatora cząstek nie-ferromagnetycznych wykorzystującego prądy wirowe)