Investigation of parameters variation of speed controller on the frequency responses in vector automatic control system

The article considers the method of adjusting the frequency converter on preset quality parameters of transients. Regulation is carried out by means of changing the parameters of proportional-integral speed controller at constant performance of closed-loop current controller. Influence of parameters the proportional-integral speed controller on frequency response of vector control system is shown. Results of the simulation and experimental investigations based on the frequency converter Siemens Sinamics S120 are given. Recommendations for adjust settings of closed-loop speed controller of the vector control system at different performance are proposed as a conclusion.В статье рассматривается методика настройки преобразователя частоты на заданные показатели качества переходного процесса. Регулирование происходит за счет изменения параметров пропорционально интегрального регулятора скорости при неизменном быстродействии контура тока. Показано влияние параметров ПИ регулятора скорости на частотные характеристики векторной системы управления и показатели качества переходных процессов. Приводятся результаты моделирования и экспериментальных исследований на базе преобразователя частоты Siemens Sinamics S120. В качестве вывода предложены рекомендации для настройки контура скорости векторных систем управления с различным быстродействием

Selection of power module and development of the circuits for frequency-controlled electric drive with microprocessor control system

This article is devoted to the creation of a test bench for the study of algorithms and control systems for frequency-controlled electric drive with microprocessor control based on the digital signal processor TMS320F28335. The requirements for choosing of the power module are formulated. The development of circuits for adaptation of logic signals levels is described.В данной статье представлена работа по созданию испытательного стенда для изучения алгоритмов и систем управления частотно-регулируемым электроприводом с микропроцессорным управлением на базе цифрового сигнального процессора TMS320F28335. Рассматриваются требования к выбору силовой части. Проводится разработка схем для согласования уровней логических сигналов

Two-dimensional array of diffusive SNS junctions with high-transparent interfaces

We report the first comparative study of the properties of two-dimensional arrays and single superconducting film - normal wire - superconducting film (SNS) junctions. The NS interfaces of our SNS junctions are really high transparent, for superconducting and normal metal parts are made from the same material (superconducting polycrystalline PtSi film). We have found that the two-dimensional arrays reveal some novel features: (i) the significant narrowing of the zero bias anomaly (ZBA) in comparison with single SNS junctions, (ii) the appearance of subharmonic energy gap structure (SGS), with up to n=16 (eV=\pm 2\Delta/n), with some numbers being lost, (iii) the transition from 2D logarithmic weak localization behavior to metallic one. Our experiments show that coherent phenomena governed by the Andreev reflection are not only maintained over the macroscopic scale but manifest novel pronounced effects as well. The behavior of the ZBA and SGS in 2D array of SNS junctions strongly suggests that the development of a novel theoretical approach is needed which would self-consistently take into account the distribution of the currents, the potentials, and the superconducting order parameter.Comment: RevTex, 5 pages, 5 figure

Investigation of the electromagnetic compatibility of a frequency-controlled electric drive with supercapacitors

In the paper, the electromagnetic compatibility of a frequency converter with a power supply is investigated. Comparison of the variants of the electric drive with conventional capacitors and supercapacitors, which are connected directly to the DC link of the frequency converter, is given. The simulation results in the MATLAB package and the experimental study of the electric drive with using the power quality analyzer are presented. The paper presents the forms of currents and voltages at the input of the frequency converter, as well as their harmonics composition. Conclusions about the influence of the supercapacitor block on the electromagnetic compatibility of electric drive to the mains are made. © 2018 I.V. Plotnikov and I.S. Uimin.17-08-00188I. V. Plotnikov and I. S. Uimin The reported study was funded by RFBR according to the research project № 17-08-0018

Anomalous Behavior near T_c and Synchronization of Andreev Reflection in Two-Dimensional Arrays of SNS Junctions

We have investigated low-temperature transport properties of two-dimensional arrays of superconductor--normal-metal--superconductor (SNS) junctions. It has been found that in two-dimensional arrays of SNS junctions (i) a change in the energy spectrum within an interval of the order of the Thouless energy is observed even when the thermal broadening far exceeds the Thouless energy for a single SNS junction; (ii) the manifestation of the subharmonic energy gap structure (SGS) with high harmonic numbers is possible even if the energy relaxation length is smaller than that required for the realization of a multiple Andreev reflection in a single SNS junction. These results point to the synchronization of a great number of SNS junctions. A mechanism of the SGS origin in two-dimensional arrays of SNS junctions, involving the processes of conventional and crossed Andreev reflection, is proposed.Comment: 5 pages, 5 figure

Градиентометрия зонной точности станков

Стаття, що пропонується є другою частиною з циклу статей, присвячених обґрунтуванню поняття зонної точності верстатів з CNC. У другій частині показано векторний характер похибки вимірювання, а також обґрунтовано вибір математичного апарату градієнта скалярного поля для їхнього опису.Offered paper is the second part of a cycle of papers devoted to a substantiation of the term of zoned accuracy of machine tools with CNC. In the second part vector character of an error of measurement is shown, and also the choice of the mathematical device of a gradient of a scalar field for its description is proved.Предлагаемая статья является второй из частью цикла статей посвященных обоснованию термина зонной точности станков с ЧПУ. Во второй части показан векторный характер погрешности измерения, а также обоснован выбор математического аппарата градиента скалярного поля для ее описания

Observational Evidence for the Associated Formation of Blobs and Raining Inflows in the Solar Corona

The origin of the slow solar wind is still a topic of much debate. The continual emergence of small transient structures from helmet streamers is thought to constitute one of the main sources of the slow wind. Determining the height at which these transients are released is an important factor in determining the conditions under which the slow solar wind forms. To this end, we have carried out a multipoint analysis of small transient structures released from a north-south tilted helmet streamer into the slow solar wind over a broad range of position angles during Carrington Rotation 2137. Combining the remote-sensing observations taken by the Solar-TErrestrial RElations Observatory (STEREO) mission with coronagraphic observations from the SOlar and Heliospheric Observatory (SOHO) spacecraft, we show that the release of such small transient structures (often called blobs), which subsequently move away from the Sun, is associated with the concomitant formation of transient structures collapsing back toward the Sun; the latter have been referred to by previous authors as "raining inflows." This is the first direct association between outflowing blobs and raining inflows, which locates the formation of blobs above the helmet streamers and gives strong support that the blobs are released by magnetic reconnection.Peer reviewe

The mathematical simulation of dc-dc coverter in the frequency-controlled electric drive with ultracapacitors

В статье рассматриваются вопросы построения математической модели силовой части DCDC преобразователя, который используется для подключения суперконденсаторов в звено постоянного тока частотно-регулируемого электропривода. Рассматривается принцип действия DC-DC преобразователя, режимы его работы, приводятся уравнения и структурная схема для описания силовой части преобразователя в составе частотно-регулируемого электропривода. В заключительной части статьи приводятся результаты моделирования.The article deals with a mathematical model of the power part of the DC-DC converter, which is used to connect the supercapacitors into the DC link of frequency-controlled electric drive. The operating principle and boost and buck modes of the DC-DC converter are considered. The functional diagram and equations for power part of DC-DC converter as a part of frequency-controlled electric drive are described. The final part of the article presents the simulations results

Continuous Monitoring of Information on Anode Current Distribution as Means of Improving the Process of Controlling and Forecasting Process Disturbances

За последние десятилетия система АСУТП электролиза достигла больших возможностей по улучшению сбора и обработки сигналов, которые обеспечивают основу для регулирования питания, теплового баланса и магнитогидродинамической (МГД) стабильности. Несмотря на значительное развитие, постоянно растут потребности в датчиках контроля, которые могут распознавать и реагировать на возникающие изменения. C 2008 г. на электролизерах опытного участка РА-400, расположенного в опытно-промышленном корпусе электролиза ОАО «РУСАЛ Саяногорск», эксплуатируется система непрерывного мониторинга информации о распределении тока по анодам, интегрированная в АСУТП СААТ-2. На протяжении промышленных испытаний система мониторинга постоянно совершенствовалась в части достоверности информации, обеспечения работоспособности оборудования в условиях агрессивных сред, а также при выполнении технологических и ремонтных операций на электролизере. Полученная информация о распределении тока по анодам позволила разработать алгоритмы, прогнозирующие на ранней стадии отклонения в питании глиноземом электролизера с последующим перераспределением по точкам автоматической подачи глинозема (АПГ), прогнозирование и распознавание технологических нарушений на подошве анодов («конуса»)The aluminum reduction process control system in recent decades has given great opportunities for improving the collection and processing of signals that provide the basis for the adjustment of feeding, thermal balance and magnetohydrodynamic (MHD) stability. Despite considerable development, there is a growing need for control sensors that can detect and respond to emerging changes. Since 2008, the cells operating in the RA-400 pilot area inside the Pilot Potroom at OJSC RUSAL Sayanogorsk have been using a system for continuous monitoring of information on anode current distribution. The system has been integrated in the ‘CAAT-2’ control system. In the course of industrial tests, the monitoring system was continuously improved – in terms of information reliability, and equipment operability in aggressive environments and during pot tending & maintenance operations. The obtained information on anode current distribution allowed for developing algorithms to detect, at an early stage, variations in cell alumina feeding, including further alumina re-distribution between feed points, and forecast and detect anode bottom problems (“spike”

An Indirect Method for Determining the Local Heat Transfer Coefficient of Gas Flows in Pipelines

An indirect method and procedure for determining the local heat transfer coefficient in experimental studies on the intensity of heat transfer at a gas–surface interface is described. The article provides an overview of modern approaches and technical devices for determining the heat flux or friction stresses on surfaces in the study of thermophysical processes. The proposed method uses a constant-temperature hot-wire anemometer and a sensor with a thread sensitive element fixed on the surface of a fluoroplastic substrate. A substrate with the sensor’s sensitive element was mounted flush with the wall of the investigated pipeline. This method is based on the Kutateladze–Leontiev approach (the laws of friction and heat transfer) and the hydrodynamic analogy of heat transfer (the Reynolds analogy): this is an assumption about the unity of momentum and heat transfer in a turbulent flow, which establishes a quantitative relationship between friction stresses on the heat exchange surface and heat transfer through this surface. The article presents a method for determining the speed of the developed measuring system. An example of a successful application of the proposed method in relation to the study of thermomechanical processes in the gas exchange systems of reciprocating internal combustion engines is described. © 2022 by the authors.Ministry of Education and Science of the Russian Federation, MinobrnaukaThe research funding from the Ministry of Science and Higher Education of the Russian Federation (Ural Federal University Program of Development within the Priority-2030 Program) is gratefully acknowledged