Pub Date : 2021-04-25DOI: 10.23939/jcpee2021.01.028
S. Syrotyuk
Atthe first stage, the structureof theZnSe crystal doped with chromium atoms (ZnCrSe)has been found by optimization procedure. At the second stage, the electronic properties of this material have been evaluated within the two approaches. The exchange-correlation functionals used here are based on the generalized gradient approximation (GGA) and the hybrid functional PBE0. The GGA approach provides the metallic state for electrons with the spin up, and for opposite spin orientation the material ZnCrSe bahaves as semiconductor, with the band gap of 2.48 eV. The hybrid functional approach also gives a gapless state for a spin up electron states, and for a spin down it provides the forbidden gap value of 2.39 eV. The magnetic moment of the unit cell, found with the two functionals, is the same and equals to 4 Bμ(Bohr magnetons). So, the calculations with the two exchange-correlation functionals provide the prediction of half-metallic properties of the ZnCrSe material, which is an interesting candidate for spintronic applications.
{"title":"The spin-polarized electronic and magnetic properties of zinc selenide heavy doped with chromium","authors":"S. Syrotyuk","doi":"10.23939/jcpee2021.01.028","DOIUrl":"https://doi.org/10.23939/jcpee2021.01.028","url":null,"abstract":"Atthe first stage, the structureof theZnSe crystal doped with chromium atoms (ZnCrSe)has been found by optimization procedure. At the second stage, the electronic properties of this material have been evaluated within the two approaches. The exchange-correlation functionals used here are based on the generalized gradient approximation (GGA) and the hybrid functional PBE0. The GGA approach provides the metallic state for electrons with the spin up, and for opposite spin orientation the material ZnCrSe bahaves as semiconductor, with the band gap of 2.48 eV. The hybrid functional approach also gives a gapless state for a spin up electron states, and for a spin down it provides the forbidden gap value of 2.39 eV. The magnetic moment of the unit cell, found with the two functionals, is the same and equals to 4 Bμ(Bohr magnetons). So, the calculations with the two exchange-correlation functionals provide the prediction of half-metallic properties of the ZnCrSe material, which is an interesting candidate for spintronic applications.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126833118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-25DOI: 10.23939/jcpee2021.01.032
Vasyl Tchaban
he differential equations of motion of electrically charged bodies in an uneven vortex electric field at all possible range of velocities are obtained in the article. In the force interaction, in addition to the two components – the Coulomb and Lorentz forces – the third component of a hitherto unknown force is involved. This component turned out to play a crucial role in the dynamics of movement. The equations are written in the usual 3D Euclidean space and physical time.This takes into account the finite speed of electric field propagation and the law of electric charge conservation. On this basis, the trajectory of the electron in an uneven electric field generated by a positively charged spherical body is simulated. The equations of motion are written in vector and coordinate forms. A physical interpretation of the obtained mathematical results is given. Examples of simulations are given.
{"title":"Radial component of vortex electric field force","authors":"Vasyl Tchaban","doi":"10.23939/jcpee2021.01.032","DOIUrl":"https://doi.org/10.23939/jcpee2021.01.032","url":null,"abstract":"he differential equations of motion of electrically charged bodies in an uneven vortex electric field at all possible range of velocities are obtained in the article. In the force interaction, in addition to the two components – the Coulomb and Lorentz forces – the third component of a hitherto unknown force is involved. This component turned out to play a crucial role in the dynamics of movement. The equations are written in the usual 3D Euclidean space and physical time.This takes into account the finite speed of electric field propagation and the law of electric charge conservation. On this basis, the trajectory of the electron in an uneven electric field generated by a positively charged spherical body is simulated. The equations of motion are written in vector and coordinate forms. A physical interpretation of the obtained mathematical results is given. Examples of simulations are given.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"212 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132370596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-25DOI: 10.23939/jcpee2021.01.020
M. Medykovskyi, R. Melnyk
The article presents the resultsof mathematical modeling of the energy-dynamic processes of a wind farm which includes a battery energy storage system (BESS). The dependence between load capacity and energy generation capabilities of the active set of a wind power plant taking into account the energy capacity of BESS has been determined. A mathematical model of the BESS has been developed. The elaborated model is compared with two other models: a black box module and a model based on equivalent circuit model. The application of the developed model provides an opportunity to optimize the energy capacity of BESS for the specified parameters and modes of operation of the wind power plant. Using the obtained results expands the possibilities of the adequate management of energy-dynamic modes of energy systems with renewable energy sources, provides mitigation of transition processes in conditions of insufficient or excessive wind speeds and consumer loads.
{"title":"Modeling the energy-dynamic modes of a wind farm with a battery energy storage system (BESS)","authors":"M. Medykovskyi, R. Melnyk","doi":"10.23939/jcpee2021.01.020","DOIUrl":"https://doi.org/10.23939/jcpee2021.01.020","url":null,"abstract":"The article presents the resultsof mathematical modeling of the energy-dynamic processes of a wind farm which includes a battery energy storage system (BESS). The dependence between load capacity and energy generation capabilities of the active set of a wind power plant taking into account the energy capacity of BESS has been determined. A mathematical model of the BESS has been developed. The elaborated model is compared with two other models: a black box module and a model based on equivalent circuit model. The application of the developed model provides an opportunity to optimize the energy capacity of BESS for the specified parameters and modes of operation of the wind power plant. Using the obtained results expands the possibilities of the adequate management of energy-dynamic modes of energy systems with renewable energy sources, provides mitigation of transition processes in conditions of insufficient or excessive wind speeds and consumer loads.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123737682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-25DOI: 10.23939/jcpee2021.01.012
M. Kostin, T. Mishchenko, O. Hoholyuk
Voltage and current are sharply variable random (stochastic) processes in traction networks of DC electric transport systems. As a result, electronic and hybrid electricity meters used in electric systems measure electric power with a large relative error that significantly exceeds that of their accuracy class. In this paper the principle of developing smart meters for accounting the electricity transmitted from traction substations to electric rolling stock through a traction network is proposed. Proposed ideas are developed on the basis of the random processes correlation theory. The meter operates in real time and monitors not a set of realizations of random voltage and current processes, but their deterministic characteristics, that is, time functions of mathematical expectations and variances which make up the background of its operating principle. The experimental implementation of the proposed principle has been conducted in the feeder zone of an A-B section of the GisDnieper Railway of Ukraine, where registration and processing of realizations of stochastic voltage and current processes obtained in real operation mode has been done. The ratios obtained for active and reactive power can be applied not only for traction power grids, but also for electric networks of external power supply of DC electric traction systems as the basis for the “smart meter” design.
{"title":"The principle of creating a \"smart\" electricity meter in electric traction networks with stochastic electromagnetic processes","authors":"M. Kostin, T. Mishchenko, O. Hoholyuk","doi":"10.23939/jcpee2021.01.012","DOIUrl":"https://doi.org/10.23939/jcpee2021.01.012","url":null,"abstract":"Voltage and current are sharply variable random (stochastic) processes in traction networks of DC electric transport systems. As a result, electronic and hybrid electricity meters used in electric systems measure electric power with a large relative error that significantly exceeds that of their accuracy class. In this paper the principle of developing smart meters for accounting the electricity transmitted from traction substations to electric rolling stock through a traction network is proposed. Proposed ideas are developed on the basis of the random processes correlation theory. The meter operates in real time and monitors not a set of realizations of random voltage and current processes, but their deterministic characteristics, that is, time functions of mathematical expectations and variances which make up the background of its operating principle. The experimental implementation of the proposed principle has been conducted in the feeder zone of an A-B section of the GisDnieper Railway of Ukraine, where registration and processing of realizations of stochastic voltage and current processes obtained in real operation mode has been done. The ratios obtained for active and reactive power can be applied not only for traction power grids, but also for electric networks of external power supply of DC electric traction systems as the basis for the “smart meter” design.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126428274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-25DOI: 10.23939/jcpee2021.01.001
A. Druzhynin
The ohmic contacts to the n-type conductivity gallium antimonide whiskers were created due to a current pulse shaper. It was established that I–V characteristics of GaSb whiskers at low temperatures are linear, regardless of the direction of current transmission. That allows using the investigated techniques to create electrical contacts and study their electrophysical characteristics. GaSb samples with a diameter of 12 μm and 20 μm were studied at temperatures 4.2 K and 77 K. A slide table with bath and microfurnace was made for welding ohmic contacts to GaSb whiskers. Gold microwire with a diameter of 30 μm was used as a contact material. The melting was carried out under the flux layer. It was revealed that the fusion is one of the most suitable methods for creating contacts to the whiskers grown by gas transport reactions.
{"title":"Ohmic contacts to n-type and p-type gallium antimonide whiskers","authors":"A. Druzhynin","doi":"10.23939/jcpee2021.01.001","DOIUrl":"https://doi.org/10.23939/jcpee2021.01.001","url":null,"abstract":"The ohmic contacts to the n-type conductivity gallium antimonide whiskers were created due to a current pulse shaper. It was established that I–V characteristics of GaSb whiskers at low temperatures are linear, regardless of the direction of current transmission. That allows using the investigated techniques to create electrical contacts and study their electrophysical characteristics. GaSb samples with a diameter of 12 μm and 20 μm were studied at temperatures 4.2 K and 77 K. A slide table with bath and microfurnace was made for welding ohmic contacts to GaSb whiskers. Gold microwire with a diameter of 30 μm was used as a contact material. The melting was carried out under the flux layer. It was revealed that the fusion is one of the most suitable methods for creating contacts to the whiskers grown by gas transport reactions.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"328 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113999402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-12DOI: 10.23939/jcpee2020.01.037
Yuriy Vasetskyi, Iryna Mazurenko
The paper deals with an approximate analytical solution of a three-dimensional problem of the theory of electromagnetic field, which is based on the use of asymptotic expansion under the condition of a strong skin-effect for a field produced by a closed current-carrying loop located near a conducting half-space. It is noted that each member of an asymptotic series is determined with an error, the value of which depends on the value of a small parameter and increases with increasing the index of series member resulting in limited number of its members. It is identified that when using the method of asymptotic expansion, the number of members of a series can be limited by the relatively small number, which is determined by the specified limits of the allowable accuracy of calculation (relative error). The authors determine the optimal number of asymptotic series members, and indicate that calculation accuracy depends on the value of a small parameter, and for a specific conducting material it depends on the field frequency and the minimum distance from external field sources to a conducting body.
{"title":"Parameters for calculation of three-dimensional electromagnetic field by asymptotic expansion method","authors":"Yuriy Vasetskyi, Iryna Mazurenko","doi":"10.23939/jcpee2020.01.037","DOIUrl":"https://doi.org/10.23939/jcpee2020.01.037","url":null,"abstract":"The paper deals with an approximate analytical solution of a three-dimensional problem of the theory of electromagnetic field, which is based on the use of asymptotic expansion under the condition of a strong skin-effect for a field produced by a closed current-carrying loop located near a conducting half-space. It is noted that each member of an asymptotic series is determined with an error, the value of which depends on the value of a small parameter and increases with increasing the index of series member resulting in limited number of its members. It is identified that when using the method of asymptotic expansion, the number of members of a series can be limited by the relatively small number, which is determined by the specified limits of the allowable accuracy of calculation (relative error). The authors determine the optimal number of asymptotic series members, and indicate that calculation accuracy depends on the value of a small parameter, and for a specific conducting material it depends on the field frequency and the minimum distance from external field sources to a conducting body.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"99 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141205545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-12DOI: 10.23939/jcpee2020.01.027
Yuriy Shapovalov
A frequency-symbolic method (FS-method) of the analysis of steady-state mode of linear parametric circuits is intended for forming their transfer functions in the frequency domain. Transfer functions are approximated by Fourier polynomials and contain a complex variable, time variable and parameters of circuit elements in the form of symbols. The coefficients of such Fourier polynomials by the FS-method are unknown in the symbolic systems of linear algebraic equations (SSLAE), and are defined as their solutions in symbolic form. In the paper we present a method of forming an approximation expression which ensures the adequacy of calculations. Examples and results of computer experiments are given. The system of functions MAOPCs based on a frequency-symbolic method is used for the optimal design of electronic devices of noise-immune hidden radio engineering systems using code signals.
{"title":"On the adequacy of the frequency-symbolic method for linear parametric circuits analysis","authors":"Yuriy Shapovalov","doi":"10.23939/jcpee2020.01.027","DOIUrl":"https://doi.org/10.23939/jcpee2020.01.027","url":null,"abstract":"A frequency-symbolic method (FS-method) of the analysis of steady-state mode of linear parametric circuits is intended for forming their transfer functions in the frequency domain. Transfer functions are approximated by Fourier polynomials and contain a complex variable, time variable and parameters of circuit elements in the form of symbols. The coefficients of such Fourier polynomials by the FS-method are unknown in the symbolic systems of linear algebraic equations (SSLAE), and are defined as their solutions in symbolic form. In the paper we present a method of forming an approximation expression which ensures the adequacy of calculations. Examples and results of computer experiments are given. The system of functions MAOPCs based on a frequency-symbolic method is used for the optimal design of electronic devices of noise-immune hidden radio engineering systems using code signals.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"115 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141205454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-12DOI: 10.23939/jcpee2020.01.019
M. Myslovych, Valerij Zvarych, Ludwiga Ostapchuk, Yuriy Hyzhko, Мaryna Hutorova
Algorithmic software for the operation of informational measuring diagnostic systems according to the Smart Grid technology and with the conditional division of the electrotechnical equipment into hierarchical levels is proposed.
根据智能电网技术和电工设备的分级条件，提出了信息测量诊断系统的操作算法软件。
{"title":"Some issues of informational support for multilevel diagnostic systems of electrotechnical equipment","authors":"M. Myslovych, Valerij Zvarych, Ludwiga Ostapchuk, Yuriy Hyzhko, Мaryna Hutorova","doi":"10.23939/jcpee2020.01.019","DOIUrl":"https://doi.org/10.23939/jcpee2020.01.019","url":null,"abstract":"Algorithmic software for the operation of informational measuring diagnostic systems according to the Smart Grid technology and with the conditional division of the electrotechnical equipment into hierarchical levels is proposed.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"115 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141205458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-12DOI: 10.23939/jcpee2020.01.011
O. Lozynskyy, Y. Marushchak, A. Lozynskyy, B. Kopchak, L. Kasha
This paper considers the stability of dynamical systems described by differential equations with fractional derivatives. In contrast to a number of works, where the differential equation describing the system may have a set of different values of fractional derivatives, and the characteristic polynomial is formed on the basis of the least common multiple for the denominators of these indicators, this article proposes forming such a polynomial in a specific j¹/³ basis and studying the stability of systems with such fractional description based on the resulting rotation angles of Hn(jl/mω) vector at a frequency change from zero to infinity. This technique is similar to the investigation of system stability by frequency criteria used for a similar problem in describing the system by differential equations in integer derivatives. The application of characteristic polynomials formed in the j¹/³ basis for the description of the processes in dynamic systems and the analysis of the stability of such systems on the basis of the frequency criterion are the essence of the scientific novelty of this paper. The article contains the following sections: problem statement, work purpose, presentation of the research material, conclusions, list of references.
{"title":"Application of frequency stability criterion for analysis of dynamic systems with characteristic polynomials formed in j1/3 basis","authors":"O. Lozynskyy, Y. Marushchak, A. Lozynskyy, B. Kopchak, L. Kasha","doi":"10.23939/jcpee2020.01.011","DOIUrl":"https://doi.org/10.23939/jcpee2020.01.011","url":null,"abstract":"This paper considers the stability of dynamical systems described by differential equations with fractional derivatives. In contrast to a number of works, where the differential equation describing the system may have a set of different values of fractional derivatives, and the characteristic polynomial is formed on the basis of the least common multiple for the denominators of these indicators, this article proposes forming such a polynomial in a specific j¹/³ basis and studying the stability of systems with such fractional description based on the resulting rotation angles of Hn(jl/mω) vector at a frequency change from zero to infinity. This technique is similar to the investigation of system stability by frequency criteria used for a similar problem in describing the system by differential equations in integer derivatives. The application of characteristic polynomials formed in the j¹/³ basis for the description of the processes in dynamic systems and the analysis of the stability of such systems on the basis of the frequency criterion are the essence of the scientific novelty of this paper. The article contains the following sections: problem statement, work purpose, presentation of the research material, conclusions, list of references.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"118 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141205427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-12DOI: 10.23939/jcpee2020.01.001
Tadeusz Kaczorek
The notions of angles between matrices and between polynomials of fractional linear systems and electrical circuits are proposed. In analysis of angles between state matrices of fractional linear systems the Hadamard product of two matrices is applied. The angles between matrices and their functions are also addressed. The angles between symmetrical and asymmetrical part of matrices are investigated. The angles between polynomials of transfer matrices of fractional linear systems are analyzed and some new properties are established.
{"title":"Angles between matrices and between polynomials in fractional linear systems and electrical circuits","authors":"Tadeusz Kaczorek","doi":"10.23939/jcpee2020.01.001","DOIUrl":"https://doi.org/10.23939/jcpee2020.01.001","url":null,"abstract":"The notions of angles between matrices and between polynomials of fractional linear systems and electrical circuits are proposed. In analysis of angles between state matrices of fractional linear systems the Hadamard product of two matrices is applied. The angles between matrices and their functions are also addressed. The angles between symmetrical and asymmetrical part of matrices are investigated. The angles between polynomials of transfer matrices of fractional linear systems are analyzed and some new properties are established.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":"88 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141205387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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