Pub Date : 2021-07-08DOI: 10.17212/1727-2769-2021-1-41-53
A. Kromm, Gennady M. Simakov, Valery Topovsky
The article discusses the features of the synthesis of a hybrid method for commutation of a three-phase inverter in a classic version of drives with direct torque control (DTC), which involves the use of relay characteristics in the flux- and torque control blocks. It is proved that the output voltage of a converter based on a B6-inverter formed by only six basic vectors (excluding the zero vector) limits further optimization of flux- and torque ripples in the electrical motors. It has also been proven that with the classical drives with direct torque control, the torque ripples on the motor shaft are indeed higher than in systems with pulse width modulation. An analysis of the method was carried out which could allow reducing the amplitude of the torque ripples when drives with direct torque control are applied for motors supplied with only basic vectors of the inverter due to the modified (hybrid) method of inverter commutation. The conditions under which the hybrid control method of the inverter is really capable of reducing the amplitude of the motor flux- and torque ripples are considered. Based on the analysis of the proposed solution, the law of hybrid control of the inverter is presented by means of the formation of additional vectors of its output voltage via basic vectors of the inverter. The advantages of the method include the simplicity of drive control under development or in the existing drive control system, the implementation of which is carried out exclusively by a software product. With the absence of iterative methods of mathematics, the resources of microprocessor control units are reduced, which makes this method even more attractive in low-budget electrical drives that do not claim to be "high-end" of control blocks. The oscillograms are shown of a flux and current of motor with direct torque control motor application only with six base vectors of the output voltage of a semiconductor inverter and a drive with direct torque control by the hybrid method with additional voltage vectors based on the basic vectors of the inverter.
{"title":"Optimization of torque ripples in direct torque control drives","authors":"A. Kromm, Gennady M. Simakov, Valery Topovsky","doi":"10.17212/1727-2769-2021-1-41-53","DOIUrl":"https://doi.org/10.17212/1727-2769-2021-1-41-53","url":null,"abstract":"The article discusses the features of the synthesis of a hybrid method for commutation of a three-phase inverter in a classic version of drives with direct torque control (DTC), which involves the use of relay characteristics in the flux- and torque control blocks. It is proved that the output voltage of a converter based on a B6-inverter formed by only six basic vectors (excluding the zero vector) limits further optimization of flux- and torque ripples in the electrical motors. It has also been proven that with the classical drives with direct torque control, the torque ripples on the motor shaft are indeed higher than in systems with pulse width modulation. An analysis of the method was carried out which could allow reducing the amplitude of the torque ripples when drives with direct torque control are applied for motors supplied with only basic vectors of the inverter due to the modified (hybrid) method of inverter commutation. The conditions under which the hybrid control method of the inverter is really capable of reducing the amplitude of the motor flux- and torque ripples are considered. Based on the analysis of the proposed solution, the law of hybrid control of the inverter is presented by means of the formation of additional vectors of its output voltage via basic vectors of the inverter. The advantages of the method include the simplicity of drive control under development or in the existing drive control system, the implementation of which is carried out exclusively by a software product. With the absence of iterative methods of mathematics, the resources of microprocessor control units are reduced, which makes this method even more attractive in low-budget electrical drives that do not claim to be \"high-end\" of control blocks. The oscillograms are shown of a flux and current of motor with direct torque control motor application only with six base vectors of the output voltage of a semiconductor inverter and a drive with direct torque control by the hybrid method with additional voltage vectors based on the basic vectors of the inverter.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"189 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123295624","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 : 2021-07-08DOI: 10.17212/1727-2769-2021-1-19-29
One of the main successes of the kinetic theory of gases is the explicit calculation of the transport coefficients of rarefied gases. However, the greatest problems arise when calculating the thermal conductivity coefficient, especially for polyatomic gases. Also, when using different potentials, it is necessary to systematically calculate the so-called Ω-integrals, which in itself is a rather difficult task. For this reason, direct numerical molecular modeling of the processes of transfer of rarefied gases, in particular, the calculation of their transfer coefficients, is also relevant. A well-known method for such modeling is the molecular dynamics method. Unfortunately, until now this method is not available for modeling the processes of rarefied gas transfer. Under nor-mal conditions, the simulation cell should contain tens or even hundreds of millions of molecules during calculations. At the same time, the numerical implementation of the molecular dynamics method is accompanied by a systematic appearance of errors, which is the reason for the appearance of dynamic chaos. With this simulation, the true phase trajectories of the system under consideration cannot be obtained. Therefore, naturally, the idea of developing a method for modeling transport processes arises, in which phase trajectories are not calculated based on Newton's laws, but are simulated, and then are used to calculate any observables. In our works, we developed a method of stochastic molecular modeling (STM) of rarefied gas transfer processes, where this idea was implemented. The efficiency of the SMM method was demonstrated by calculating the coefficients of self-diffusion, diffusion, and viscosity of both monoatomic gases and polyatomic gases. At the same time, the possibility of modeling the most complex transfer process – the energy transfer process – has not yet been considered. This work aims to simulate the thermal conductivity coefficient by the SMM method. Both monoatomic (Ar, Kr, Ne, Xe) and polyatomic gases (CH4, O2) were considered.
{"title":"Simulation of thermal conductivity of rare gases by the stochastic method","authors":"","doi":"10.17212/1727-2769-2021-1-19-29","DOIUrl":"https://doi.org/10.17212/1727-2769-2021-1-19-29","url":null,"abstract":"One of the main successes of the kinetic theory of gases is the explicit calculation of the transport coefficients of rarefied gases. However, the greatest problems arise when calculating the thermal conductivity coefficient, especially for polyatomic gases. Also, when using different potentials, it is necessary to systematically calculate the so-called Ω-integrals, which in itself is a rather difficult task. For this reason, direct numerical molecular modeling of the processes of transfer of rarefied gases, in particular, the calculation of their transfer coefficients, is also relevant. A well-known method for such modeling is the molecular dynamics method. Unfortunately, until now this method is not available for modeling the processes of rarefied gas transfer. Under nor-mal conditions, the simulation cell should contain tens or even hundreds of millions of molecules during calculations. At the same time, the numerical implementation of the molecular dynamics method is accompanied by a systematic appearance of errors, which is the reason for the appearance of dynamic chaos. With this simulation, the true phase trajectories of the system under consideration cannot be obtained. Therefore, naturally, the idea of developing a method for modeling transport processes arises, in which phase trajectories are not calculated based on Newton's laws, but are simulated, and then are used to calculate any observables. In our works, we developed a method of stochastic molecular modeling (STM) of rarefied gas transfer processes, where this idea was implemented. The efficiency of the SMM method was demonstrated by calculating the coefficients of self-diffusion, diffusion, and viscosity of both monoatomic gases and polyatomic gases. At the same time, the possibility of modeling the most complex transfer process – the energy transfer process – has not yet been considered. This work aims to simulate the thermal conductivity coefficient by the SMM method. Both monoatomic (Ar, Kr, Ne, Xe) and polyatomic gases (CH4, O2) were considered.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116117688","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 : 2021-07-08DOI: 10.17212/1727-2769-2021-1-54-61
Grigory Tyrin, V. Frolovsky
The problem of geometric covering is a special case of the optimal design problem and belongs to the class of cutting and packing problems. The challenge is to position some geometric objects on the surface to be coated so that the entire surface is covered. The complexity of the problems under consideration is due to their belonging to the class of NP-hard problems, which excludes the possibility of solving them by exact methods and requires the development of approximate optimization methods and algorithms. This article discusses the problem of geometric covering of an area with circles from a given set of radii. To solve the problem of geometric covering, a hexagonal grid coverage method with optimization by a metaheuristic algorithm is used. The crow search algorithm is such an algorithm, which is a relatively new metaheuristic algorithm based on the intelligent behavior of crows in a flock. The crow search algorithm includes two control parameters: the awareness probability and the flight length. To study the solution method and check the efficiency, a problem was modeled on the basis of a real design of automatic irrigation systems, and the results of experiments with different values of control parameters were presented.
{"title":"Research and application of the crow search algorithm for geometric covering optimization problems","authors":"Grigory Tyrin, V. Frolovsky","doi":"10.17212/1727-2769-2021-1-54-61","DOIUrl":"https://doi.org/10.17212/1727-2769-2021-1-54-61","url":null,"abstract":"The problem of geometric covering is a special case of the optimal design problem and belongs to the class of cutting and packing problems. The challenge is to position some geometric objects on the surface to be coated so that the entire surface is covered. The complexity of the problems under consideration is due to their belonging to the class of NP-hard problems, which excludes the possibility of solving them by exact methods and requires the development of approximate optimization methods and algorithms. This article discusses the problem of geometric covering of an area with circles from a given set of radii. To solve the problem of geometric covering, a hexagonal grid coverage method with optimization by a metaheuristic algorithm is used. The crow search algorithm is such an algorithm, which is a relatively new metaheuristic algorithm based on the intelligent behavior of crows in a flock. The crow search algorithm includes two control parameters: the awareness probability and the flight length. To study the solution method and check the efficiency, a problem was modeled on the basis of a real design of automatic irrigation systems, and the results of experiments with different values of control parameters were presented.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122446025","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 : 2021-07-08DOI: 10.17212/1727-2769-2021-1-30-40
A. Glushak
The study is devoted to the development of a data collection module of the electromagnetic calorimeter of the Super c-τ factory collider. The data collection module is one of the main parts of the data acquisition system of the electromagnetic calorimeter. It is designed for analog and digital signal processing of scintillation counters, calculating its main characteristics (amplitude, time of occurrence and quality of fitting), and participates in the launch of the detector data acquisition system. A prototype of the module on which the module will be debugged and the algorithm of the device will be checked is being developed. The algorithm of the module includes the calculation of signal characteristics and the formation of packets for data transmission. Signal characteristics are calculated by approximating a function defined either by the least squares method or by the method of χ2 function minimization. In the course of a mathematical experiment, it was found that the method of χ2 function minimization gave more accurate calculation values than the least squares method. However, it requires an experiment with scintillation counters to determine the necessary coefficients. Therefore, the coefficients of the approximating curve are determined by the least squares method in the proto-type and the method of χ2 function minimization is used in the module. Based on the results obtained, an algorithm of the module operation was compiled, which was then implemented in the field-programmable gate array Altera Cyclone 10GX.
{"title":"Structure and operation algorithm of the data collection module of the Super c-τ factory electromagnetic calorimeter","authors":"A. Glushak","doi":"10.17212/1727-2769-2021-1-30-40","DOIUrl":"https://doi.org/10.17212/1727-2769-2021-1-30-40","url":null,"abstract":"The study is devoted to the development of a data collection module of the electromagnetic calorimeter of the Super c-τ factory collider. The data collection module is one of the main parts of the data acquisition system of the electromagnetic calorimeter. It is designed for analog and digital signal processing of scintillation counters, calculating its main characteristics (amplitude, time of occurrence and quality of fitting), and participates in the launch of the detector data acquisition system. A prototype of the module on which the module will be debugged and the algorithm of the device will be checked is being developed. The algorithm of the module includes the calculation of signal characteristics and the formation of packets for data transmission. Signal characteristics are calculated by approximating a function defined either by the least squares method or by the method of χ2 function minimization. In the course of a mathematical experiment, it was found that the method of χ2 function minimization gave more accurate calculation values than the least squares method. However, it requires an experiment with scintillation counters to determine the necessary coefficients. Therefore, the coefficients of the approximating curve are determined by the least squares method in the proto-type and the method of χ2 function minimization is used in the module. Based on the results obtained, an algorithm of the module operation was compiled, which was then implemented in the field-programmable gate array Altera Cyclone 10GX.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131063866","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 : 2021-01-20DOI: 10.17212/1727-2769-2020-4-51-61
A. Chekhonadskikh
We take as the research object the well-known system of nonlinear differential and functional equations that describes a synchronous generator. PIDD2-control was carried out through the excitation block. Effective values of the steady state in relative units and the preliminary settings of suboptimal controllers were obtained earlier using a linearized model. Disturbing surges (spikes and slump) in bus voltages were modeled as line impedance changes. The system stabilization was studied at various surges values and controller parameters by means series of numerical experiments; the calculations were carried out by the methods of Runge-Kutta and Dorman-Prince. The main attention was paid to various transient types, both stabilizing and diverging, as well as a configuration of the stability region boundary in the controller parameters of and a surge magnitude; the paper presents the results for the proportional control parameter are as the most informative. We've identified five types of transients and several important features of the model's behavior near the stabilization area boundary. Thus, the nonlinear model turned out to be unstable to small and stable to bigger perturbations in the unstable area of its linearization. The steady-state oscillations at the boundary have a lower amplitude with increasing of an initial perturbation, etc.
{"title":"Stability area of a synchronous generator nonlinear model with multiparametric excitation controller","authors":"A. Chekhonadskikh","doi":"10.17212/1727-2769-2020-4-51-61","DOIUrl":"https://doi.org/10.17212/1727-2769-2020-4-51-61","url":null,"abstract":"We take as the research object the well-known system of nonlinear differential and functional equations that describes a synchronous generator. PIDD2-control was carried out through the excitation block. Effective values of the steady state in relative units and the preliminary settings of suboptimal controllers were obtained earlier using a linearized model. Disturbing surges (spikes and slump) in bus voltages were modeled as line impedance changes. The system stabilization was studied at various surges values and controller parameters by means series of numerical experiments; the calculations were carried out by the methods of Runge-Kutta and Dorman-Prince. The main attention was paid to various transient types, both stabilizing and diverging, as well as a configuration of the stability region boundary in the controller parameters of and a surge magnitude; the paper presents the results for the proportional control parameter are as the most informative. We've identified five types of transients and several important features of the model's behavior near the stabilization area boundary. Thus, the nonlinear model turned out to be unstable to small and stable to bigger perturbations in the unstable area of its linearization. The steady-state oscillations at the boundary have a lower amplitude with increasing of an initial perturbation, etc.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121525186","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 : 2020-12-18DOI: 10.17212/1727-2769-2020-3-37-51
A. Elshin, V. Kozhukhov, Petr Elshin
The article presents the design features of inductive-conductive heaters, determines the relationship between electromagnetic loads, material properties and dimensions of the heat exchanger, presents the results of compiling a universal dependence of the main parameters of inductive-conductive heaters as a function of heat output, frequency and voltage value. Values determined by the properties and cost of materials, conditions of heat resistance and electrical safety, technological capabilities of production and operating conditions are taken as design constants. These values are selected at the beginning of the design and remain constant until the results of the calculation of the acceptable basic dimensions of the device are obtained. Nomograms of the dependence of the wall thickness of the heating chamber on the value of the current density and heat flux were obtained. The choice of the optimal design result is carried out by means of an economic assessment of the investigated options from the point of view of minimizing the cost of production and losses of electricity during the operation of the electric heater. An algorithm for designing the main dimensions of single-phase and three-phase inductive-conductive heaters with a capacity of 1 to 250 kW per unit of a product for a voltage of 0.4 kV and a frequency of 50 Hz is given and the results of calculating the main mass-cost indicators are presented. The analysis of the calculated data indicates the preference of electric heaters with a higher heat output in terms of specific cost and specific weight. At the same time, the relative capital costs of funds per unit mass of the product remain practically constant.
{"title":"Fundamentals of designing inductive-conductive heaters","authors":"A. Elshin, V. Kozhukhov, Petr Elshin","doi":"10.17212/1727-2769-2020-3-37-51","DOIUrl":"https://doi.org/10.17212/1727-2769-2020-3-37-51","url":null,"abstract":"The article presents the design features of inductive-conductive heaters, determines the relationship between electromagnetic loads, material properties and dimensions of the heat exchanger, presents the results of compiling a universal dependence of the main parameters of inductive-conductive heaters as a function of heat output, frequency and voltage value. Values determined by the properties and cost of materials, conditions of heat resistance and electrical safety, technological capabilities of production and operating conditions are taken as design constants. These values are selected at the beginning of the design and remain constant until the results of the calculation of the acceptable basic dimensions of the device are obtained. Nomograms of the dependence of the wall thickness of the heating chamber on the value of the current density and heat flux were obtained. The choice of the optimal design result is carried out by means of an economic assessment of the investigated options from the point of view of minimizing the cost of production and losses of electricity during the operation of the electric heater. An algorithm for designing the main dimensions of single-phase and three-phase inductive-conductive heaters with a capacity of 1 to 250 kW per unit of a product for a voltage of 0.4 kV and a frequency of 50 Hz is given and the results of calculating the main mass-cost indicators are presented. The analysis of the calculated data indicates the preference of electric heaters with a higher heat output in terms of specific cost and specific weight. At the same time, the relative capital costs of funds per unit mass of the product remain practically constant.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116951080","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 : 2020-12-18DOI: 10.17212/1727-2769-2020-3-13-20
G. Devyatkov
When solving problems of broadband matching, very often there is a need for a certain form of the amplitude-frequency characteristic. In connection with this, the problem comes up of synthesizing broadband matching devices that simultaneously have correcting properties, i.e. having a given frequency dependence of the power conversion coefficient in the operating frequency band. The use of broadband reactive matching - correcting circuits in most practical cases is difficult because of the reflected power. This leads to the problem of the synthesis of broadband matching-correcting circuits with arbitrary immittances of the signal source and load in an elemental basis of a general form, containing along with reactive and active elements, which has not been adequately solved. Therefore, it becomes necessary to find the conditions for the physical realizability of a typical component of the immitance matrix of a two-port network of general form containing poles in the left half-plane of complex frequencies. In this paper the necessary and sufficient conditions are defined for the physical realizability of the immitance matrix of a typical component of a subclass of two-terminal networks of general form in a lumped elemental electric basis, when the poles of the Eigen functions in the Foster representation can be in the left half-plane of complex frequencies, excluding the imaginary and real axes. This allows to synthesis of broadband dissipative matching, matching-correcting circuits and matched attenuators in an elemental basis of a general form with arbitrary immitances of the signal source and load from a single point of view.
{"title":"Conditions for the physical realizability of a typical component z(y)-matrix of a matching quadrupole of a general form in a concentrated elemental basis","authors":"G. Devyatkov","doi":"10.17212/1727-2769-2020-3-13-20","DOIUrl":"https://doi.org/10.17212/1727-2769-2020-3-13-20","url":null,"abstract":"When solving problems of broadband matching, very often there is a need for a certain form of the amplitude-frequency characteristic. In connection with this, the problem comes up of synthesizing broadband matching devices that simultaneously have correcting properties, i.e. having a given frequency dependence of the power conversion coefficient in the operating frequency band. The use of broadband reactive matching - correcting circuits in most practical cases is difficult because of the reflected power. This leads to the problem of the synthesis of broadband matching-correcting circuits with arbitrary immittances of the signal source and load in an elemental basis of a general form, containing along with reactive and active elements, which has not been adequately solved. Therefore, it becomes necessary to find the conditions for the physical realizability of a typical component of the immitance matrix of a two-port network of general form containing poles in the left half-plane of complex frequencies. In this paper the necessary and sufficient conditions are defined for the physical realizability of the immitance matrix of a typical component of a subclass of two-terminal networks of general form in a lumped elemental electric basis, when the poles of the Eigen functions in the Foster representation can be in the left half-plane of complex frequencies, excluding the imaginary and real axes. This allows to synthesis of broadband dissipative matching, matching-correcting circuits and matched attenuators in an elemental basis of a general form with arbitrary immitances of the signal source and load from a single point of view.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"441 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120869686","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 : 2020-12-18DOI: 10.17212/1727-2769-2020-3-62-74
I. Palchikova, Elena Karamchuk, E. S. Smirnov, E. Palchikov, M. Samoylenko
Features of the development of the multifunctional semiconductor illuminators are discussed. The design and characteristics of the experimental model of the “Photobox 3138” illuminator are described. The lighting variation does not exceed 2 % at the edges of the working field of 300*300 mm. The design includes a white LED illuminator with a color temperature of 5000 K (CIE D50) and a high color rendering index (CRI 97+) and a set of six independently switched monochrome led illuminators in the spectral range from 365 to 880 nm. Digital images of objects obtained in “Photobox 3138” are of use to colorimetric, spectrozonal, and multispectral analysis.
{"title":"Multi-functional semiconductor lighting","authors":"I. Palchikova, Elena Karamchuk, E. S. Smirnov, E. Palchikov, M. Samoylenko","doi":"10.17212/1727-2769-2020-3-62-74","DOIUrl":"https://doi.org/10.17212/1727-2769-2020-3-62-74","url":null,"abstract":"Features of the development of the multifunctional semiconductor illuminators are discussed. The design and characteristics of the experimental model of the “Photobox 3138” illuminator are described. The lighting variation does not exceed 2 % at the edges of the working field of 300*300 mm. The design includes a white LED illuminator with a color temperature of 5000 K (CIE D50) and a high color rendering index (CRI 97+) and a set of six independently switched monochrome led illuminators in the spectral range from 365 to 880 nm. Digital images of objects obtained in “Photobox 3138” are of use to colorimetric, spectrozonal, and multispectral analysis.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"148 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125328566","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 : 2020-12-18DOI: 10.17212/1727-2769-2020-3-7-12
D. Volkhin, G. Devyatkov
The problem of broadband matching of active elements in terms of noise figure is inevitably encountered in the design of broadband low-noise microwave amplifiers. Despite the fact that this problem differs from the classical problem of broadband matching of signal source and load, it can be reduced to a form suitable for applying methods for solving the classical problem. For this purpose, in this work, the own parameters of a reactive two-port network are derived that match active elements in terms of noise figure in the entire frequency band, where the data for calculating this coefficient are determined. The own parameters of such a two-port network, on the one hand, make it possible to construct methods for the synthesis of input matching circuits of low-noise amplifiers and other devices where low noise matching is required. On the other hand, the own parameters allow one to construct estimates of the maximum achievable bandwidth for a matching circuit of a given complexity.
{"title":"Own parameters of an ideal two-port for low noise matching","authors":"D. Volkhin, G. Devyatkov","doi":"10.17212/1727-2769-2020-3-7-12","DOIUrl":"https://doi.org/10.17212/1727-2769-2020-3-7-12","url":null,"abstract":"The problem of broadband matching of active elements in terms of noise figure is inevitably encountered in the design of broadband low-noise microwave amplifiers. Despite the fact that this problem differs from the classical problem of broadband matching of signal source and load, it can be reduced to a form suitable for applying methods for solving the classical problem. For this purpose, in this work, the own parameters of a reactive two-port network are derived that match active elements in terms of noise figure in the entire frequency band, where the data for calculating this coefficient are determined. The own parameters of such a two-port network, on the one hand, make it possible to construct methods for the synthesis of input matching circuits of low-noise amplifiers and other devices where low noise matching is required. On the other hand, the own parameters allow one to construct estimates of the maximum achievable bandwidth for a matching circuit of a given complexity.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"334 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134066137","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 : 2020-12-18DOI: 10.17212/1727-2769-2020-3-21-36
R. Deeb
Tube bundles can be used as a separation heat exchanger in the organic Rankine cycle power plants (ORC), while the hot gas passes over the outer surface, and the working substance ORC flows inside the tubes. A numerical study has been conducted to clarify heat transfer and hydrodynamics of a cross-flow heat exchanger with staggered drop-shaped tubes at different flow angles of attack in comparison with circular tubes of the same equivalent diameter. The study was performed for the Reynolds number Re= 1.8 103 ~ 9.4 103, the longitudinal and transverse spacing of the tubes in the bundle are the same and are equal to 37 mm. Four cases of the tube’s arrangement with different angles of attack were investigated: 0, 45, 135, and 180 angles. The article presents a literature review related to the subject of the study. A mathematical and numerical model has been developed to calculate the heat transfer coefficient of the studied staggered drop-shaped tubes bundle using the ANSYS package, taking into account the stress-strain state of the tubes. Correlations of the average Nusselt numbers and the friction coefficient for the considered bundles in terms of the Reynolds number and angle of attack were presented. The results reveal that the thermal–hydraulic performance of the drop-shaped tubes bundle with zero-angle of attack is about 1.6 ~ 1.7 times greater than the circular one.
{"title":"Effect of angle of attack on heat transfer and hydrodynamic characteristics for staggered drop-shaped tubes bundle in cross-flow","authors":"R. Deeb","doi":"10.17212/1727-2769-2020-3-21-36","DOIUrl":"https://doi.org/10.17212/1727-2769-2020-3-21-36","url":null,"abstract":"Tube bundles can be used as a separation heat exchanger in the organic Rankine cycle power plants (ORC), while the hot gas passes over the outer surface, and the working substance ORC flows inside the tubes. A numerical study has been conducted to clarify heat transfer and hydrodynamics of a cross-flow heat exchanger with staggered drop-shaped tubes at different flow angles of attack in comparison with circular tubes of the same equivalent diameter. The study was performed for the Reynolds number Re= 1.8 103 ~ 9.4 103, the longitudinal and transverse spacing of the tubes in the bundle are the same and are equal to 37 mm. Four cases of the tube’s arrangement with different angles of attack were investigated: 0, 45, 135, and 180 angles. The article presents a literature review related to the subject of the study. A mathematical and numerical model has been developed to calculate the heat transfer coefficient of the studied staggered drop-shaped tubes bundle using the ANSYS package, taking into account the stress-strain state of the tubes. Correlations of the average Nusselt numbers and the friction coefficient for the considered bundles in terms of the Reynolds number and angle of attack were presented. The results reveal that the thermal–hydraulic performance of the drop-shaped tubes bundle with zero-angle of attack is about 1.6 ~ 1.7 times greater than the circular one.","PeriodicalId":448354,"journal":{"name":"Proceedings of the Russian higher school Academy of sciences","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115381931","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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