Improved Control System Analysis of Frequency Converters Active Rectifiers as a Part of Rolling Mill Electric Drives

Frequency converters with active rectifiers (FC-AR) are now used in rolling mill electric drives. Modern control systems of ARs are not adapted to voltage sags in power supply systems, which leads to converter tripping. The known methods of ensuring AR operation stability, such as kinetic buffering, correction signals based on negative sequence voltage and others, do not eliminate these emergency trips. As an additional measure the paper proposes the method of voltage sag compensation by using static var compensators (SVC) of electric arc furnaces (EAF) for parallel operation of frequency converters with active rectifiers and electric arc furnaces. However, it remains unknown how disturbances (such as overvoltages of switching of SVC harmonic filters (HF) and voltage sags during furnace transformer switching) affect operation stability of frequency converters with active rectifiers. All this makes it necessary to study the effect of these processes on the operation conditions of FC-AR and to improve the active rectifier control system. The authors used experimental arrays of instantaneous values of voltages and currents of the real-life complex «EAF-SVC» («Electric Arc Furnace – Statistic VAR Compensator») in this study. They also applied mathematical models of FC-AR with different PWM algorithms realized in Matlab-Simulink software. The main assumption of the model consists in using equivalent current sources modelling the operation of autonomous voltage invertors. An improved control system of AR has been developed. The main feature that distinguishes it from the known systems is the fact that it ensures operation stability during SVC harmonic filter and EAF transformer switching by using a signal conditioning unit for setting the active rectifier reactive current component as a function of power supply and AR input voltage difference. Implementation of the improved AR control system improves FC-AR stability during parallel operation with EAFs through reactive power consumption of the supply system. As a result, it reduces the amplitude of inrush current and voltage deviations in the DC-link of the FC-AR to the values lower than the setpoints of the AR protection system.

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Improving the control system of the wire laying unit of the thin drawing mill

Informacionno-technologicheskij vestnik ◽

10.21499/2409-1650-2020-23-1-71-75 ◽

2020 ◽

pp. 71-75

Author(s):

А.В. Белый

Keyword(s):

Control System ◽

Functional Diagram ◽

Protection System ◽

Electric Drives ◽

Frequency Converters ◽

Mode Of Operation ◽

Reversal Mechanism ◽

The Wire ◽

Winding Wire ◽

Drawing Mill

В статье приводится описание разработки усовершенствованной системы регулирования аппарата укладки проволоки на стане тонкого волочения. Модернизация системы регулирования направлена на устранение недопустимого режима работы стана, когда намотка проволоки на катушку осуществляется без ее равномерной укладки, вследствие выхода из строя механизма реверсирования укладчика. Разработана функциональная схема системы защиты от остановки укладчика в процессе намотки проволоки на катушку. Реализация данной схемы выполнена на базе существующих систем регулирования преобразователей частоты в электроприводах аппаратов намотки и укладки. Приведено описание работы защиты от остановки укладчика. The article describes the development of an improved system for regulating the apparatus for laying wire on a thin drawing mill. The modernization of the control system is aimed at eliminating the unacceptable mode of operation of the mill, when the wire is wound on a coil without evenly stacking it, due to failure of the stacker reversal mechanism. A functional diagram of the stacker stop protection system was developed during the process of winding wire onto a spool. The implementation of this scheme is based on existing systems for regulating frequency converters in electric drives of winding and stacking machines. The description of the operation of the protection against stopping the stacker is given.

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SYNTHESIS OF A FUZZY TWO-LINKED REGULATOR FOR FREQUENCY ELECTRIC DRIVES OF A GRAIN MACHINE WITH A FOCUS OF THE GRAIN FLOW

Electromechanical and energy saving systems ◽

10.30929/2072-2052.2021.3.55.16-23 ◽

2021 ◽

Vol 3 (55) ◽

pp. 16-23

Author(s):

E. Burdilna ◽

◽

І. Konokh ◽

S. Serhiienko

Keyword(s):

Control System ◽

Fuzzy System ◽

Fuzzy Controller ◽

Practical Application ◽

Electric Drives ◽

Frequency Converters ◽

Grain Flow ◽

Microprocessor Control System ◽

Working Bodies ◽

Definition Of

Purpose. A control system for grain overloading during post-harvest processing with grain throwers has been proposed, the use of which will reduce damage and grain loss. An automated electromechanical system is presented that can be installed on agricultural machinery without additional modernization of the working bodies. Methodology. As a result of the analysis of control systems, a system with elements of fuzzy logic was selected, which will clearly define the necessary control actions and take into account additional parameters that can affect the overload process. A functional diagram of a microprocessor control system for an electric drive using a fuzzy system is proposed. The result of the system operation will be the definition of the control task for the frequency converters of the drive motors of the grain thrower mechanisms. Originality. Based on the simulation of grain flight trajectories, the dependences of the flight range on the conveyor speed and additional blowing were formed, which were used to determine the settings of the fuzzy controller. Results. Fuzzy system settings are performed: a set of input and output variables is defined; the number and location of terms are selected; a set of production rules for the system is formulated. As a result of experimental modeling, graphs of the formation of mastering influences by a fuzzy controller under the condition of the appearance and disappearance of the headwind for different given distances of movement were obtained. Practical value. Practical application of the offered system will allow to reduce material losses from injury of the overloaded grain and to increase efficiency of work of the grain thrower. Figures 8, references 21.

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Improving the Stability of Operation of Electric Drives on the Basis of Frequency Converters with Active Rectifiers During the External Voltage Drops and Parallel Operation with Electric Arc Furnace

Electrotechnical Systems and Complexes ◽

10.18503/2311-8318-2020-3(48)-33-40 ◽

2020 ◽

pp. 33-40

Author(s):

Alexander Nikolaev ◽

◽

Alexander Denisevich ◽

Igor Lozhkin ◽

Veronika Laptova ◽

...

Keyword(s):

Electric Arc Furnace ◽

Electric Arc ◽

Arc Furnace ◽

Parallel Operation ◽

External Voltage ◽

Electric Drives ◽

Frequency Converters ◽

Voltage Drops ◽

The Stability ◽

Active Rectifiers

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Control System for Interconnected Electric Drives with an Electromechanical Torsion and Load Distribution

Vestnik MEI ◽

10.24160/1993-6982-2019-3-70-79 ◽

2019 ◽

Vol 3 (3) ◽

pp. 70-79

Author(s):

Igor S. Polyushchenkov ◽

Keyword(s):

Control System ◽

Load Distribution ◽

Electric Drives

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Developing an effective diagnosis for safety improvement in steelworks

Occupational Ergonomics ◽

10.3233/oer-2004-4403 ◽

2005 ◽

Vol 4 (4) ◽

pp. 229-240

Author(s):

A.R. Hale ◽

H.A. v.d. Waterbeemd ◽

R. Potter ◽

B.H. Heming ◽

P.H.J.J. Swuste ◽

...

Keyword(s):

Control System ◽

Cold Rolling ◽

Rolling Mill ◽

Safety Management ◽

Risk Control ◽

Cold Rolling Mill ◽

Rich Picture ◽

Safety Improvement ◽

Effective Diagnosis ◽

Current Risk

The paper describes the methods used for a study of the safety management system and culture of a cold rolling mill in a steel plant. It uses data from diverse sources which can be validated against each other and combined to produce a rich picture of the current risk control system and its shortcomings. The paper also describes the proposed improvements and what the plant chose to implement. This step also throws light on the culture of the plant.

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VILNIUS ADVANCED-SURFACE MOVEMENT GUIDANCE AND CONTROL SYSTEM (A-SMGCS) SAFETY OBJECTIVES / VILNIAUS AERODROMO AUTOMATIZUOTOS ANTŽEMINIO EISMO STEBĖJIMO IR KONTROLĖS SISTEMOS SAUGOS TIKSLŲ ANALIZĖ

Aviation ◽

10.3846/16487788.2012.753677 ◽

2012 ◽

Vol 16 (4) ◽

pp. 130-135

Author(s):

Vaidotas Kondroška ◽

Jonas Stankūnas

Keyword(s):

Control System ◽

System Analysis ◽

Flight Safety ◽

Frequency Of Occurrence ◽

Surface Movement ◽

Safety Requirements ◽

Methods Of Determination ◽

Guidance And Control ◽

System A ◽

And Control

This work reviews the innovative and progressive methods of determination and analysis of safety objectives using Vilnius A-SMGCS example. The aim of the analysis is to determine how failures in this system could affect flight safety in Vilnius aerodrome. Identified safety objectives will limit the frequency of occurrence of hazards enough for the associated risk to be acceptable, and will ensure that appropriate mitigation means are reflected subsequently as Safety Requirements for the system. Analysis reflects aspects of A-SMGCS Safety objectives, which should be taken into consideration. Santrauka Darbe apžvelgiami progresyvūs saugos tikslų analizės metodai pagal Vilniaus aerodromo automatizuotos antžeminio eismo stebėjimo ir kontrolės sistemos veiklos pavyzdį. Analizuojama, kaip šios sistemos sutrikimai gali paveikti skrydžių saugą Vilniaus aerodrome. Remiantis galimų pavojų skrydžių saugai analize, tyrime nustatyti saugos tikslai, pagal kuriuos vėliau bus numatomos riziką mažinančios priemonės (galimų pavojų neutralizavimui ar kylančios rizikos sumažinimui iki priimtino lygio). Straipsnyje pateikiami veiksniai, kuriuos reikėtų įvertinti nustatant aerodromo automatizuotos antžeminio eismo stebėjimo ir kontrolės sistemos saugos tikslus.

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