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Current control of battery pack modules in parallel connection according to SoC
Mario Vražić, Antonio Persic, Peter Virtič, Tomislav Ivanis, 2023, izvirni znanstveni članek

Opis: Electric vehicles, especially cars, have been in the spotlight for some time now. In the focus of environmentalists, engineers, users, media, etc. With the growth and advancement of the market for such vehicles, other electric vehicles are also focussing on. One of such vehicles is boats, particularly smaller boats up to 8–10 meters in length. Of course, the biggest problem here is charging. The general idea is to use battery modules that can be easily carried and enable hot swapping. This paper investigates scenarios and simulations of the control system for hot swapping of the battery module. Simulations of connection of two and three battery modules to parallel operation and current control are presented in this paper, as well as applied control rules.
Ključne besede: battery pack, battery modules, parallel connection, Bidirectional multiple input single output synchronous DC/DC converter, BMISO DC/DC converter, Hotplugin, Smart SoC control, Advanced SoC control
Objavljeno v DKUM: 08.04.2024; Ogledov: 184; Prenosov: 5
.pdf Celotno besedilo (880,89 KB)
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Reduction of surface defects by optimization of casting speed using genetic programming : an industrial case study
Miha Kovačič, Uroš Župerl, Leo Gusel, Miran Brezočnik, 2023, izvirni znanstveni članek

Opis: Štore Steel Ltd. produces more than 200 different types of steel with a continuous caster installed in 2016. Several defects, mostly related to thermomechanical behaviour in the mould, originate from the continuous casting process. The same casting speed of 1.6 m/min was used for all steel grades. In May 2023, a project was launched to adjust the casting speed according to the casting temperature. This adjustment included the steel grades with the highest number of surface defects and different carbon content: 16MnCrS5, C22, 30MnVS5, and 46MnVS5. For every 10 °C deviation from the prescribed casting temperature, the speed was changed by 0.02 m/min. During the 2-month period, the ratio of rolled bars with detected surface defects (inspected by an automatic control line) decreased for the mentioned steel grades. The decreases were from 11.27 % to 7.93 %, from 12.73 % to 4.11 %, from 16.28 % to 13.40 %, and from 25.52 % to 16.99 % for 16MnCrS5, C22, 30MnVS5, and 46MnVS5, respectively. Based on the collected chemical composition and casting parameters from these two months, models were obtained using linear regression and genetic programming. These models predict the ratio of rolled bars with detected surface defects and the length of detected surface defects. According to the modelling results, the ratio of rolled bars with detected surface defects and the length of detected surface defects could be minimally reduced by 14 % and 189 %, respectively, using casting speed adjustments. A similar result was achieved from July to November 2023 by adjusting the casting speed for the other 27 types of steel. The same was predicted with the already obtained models. Genetic programming outperformed linear regression.
Ključne besede: continuous casting of steel, surface defects, automatic control, machine learning, modelling, optimisation, prediction, linear regression, genetic programming
Objavljeno v DKUM: 25.03.2024; Ogledov: 150; Prenosov: 9
.pdf Celotno besedilo (1,19 MB)
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LiDAR-Based Maintenance of a Safe Distance between a Human and a Robot Arm
David Podgorelec, Suzana Uran, Andrej Nerat, Božidar Bratina, Sašo Pečnik, Marjan Dimec, Franc Žaberl, Borut Žalik, Riko Šafarič, 2023, izvirni znanstveni članek

Opis: This paper focuses on a comprehensive study of penal policy in Slovenia in the last 70 years, providing an analysis of statistical data on crime, conviction, and prison populations. After a sharp political and penal repression in the first years after World War II, penal and prison policy began paving the way to a unique "welfare sanction system", grounded in ideas of prisoners' treatment. After democratic reforms in the early 1990s, the criminal legislation became harsher, but Slovenia managed to avoid the general punitive trends characterized by the era of penal state and culture of control. The authoritarian socialist regime at its final stage had supported the humanization of the penal system, and this trend continued in the first years of the democratic reforms in the 1990s, but it lost its momentum after 2000. In the following two decades, Slovenia experienced a continuous harshening of criminal law and sanctions on the one hand and an increasing prison population rate on the other. From 2014 onwards, however, there was a decrease in all segments of penal statistics. The findings of the study emphasize the exceptionalism of Slovenian penal policy, characterized by penal moderation, which is the product of the specific local historical, political, economic, and normative developments.
Ključne besede: LIDAR, robot, human-robot collaboration, speed and separation monitoring, intelligent control system, geometric data registration, motion prediction
Objavljeno v DKUM: 16.02.2024; Ogledov: 257; Prenosov: 17
.pdf Celotno besedilo (5,27 MB)
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Event-triggered second-order sliding mode controller design and implementation
Andrej Sarjaš, Dušan Gleich, 2023, izvirni znanstveni članek

Opis: The paper presents an event-triggered higher-order sliding mode controller design. The event-triggering technique is the alternative approach to real-time controller execution, unlike the classic time-triggering technique, which is not time-dependable and is governed by the triggering policy. The technique is suitable for system resource relaxation in case of computation burden or network usage mitigation. The paper describes the stability analysis of the super-twisted sliding mode controller based on input-to-state stability notation. The stability analysis introduces a triggering policy related directly to the ultimate boundness of the system states and preselected sliding variables. The controller time execution with the selected triggering condition prevents the exhibition of the Zeno phenomena, where the minimal inter-event time of the controller has a positive non-zero lower bound. The minimal value of the inter-event time is related directly to the controller parameters and triggering bound, the selection of which is given with the derived stability conditions regarding the designer’s objective. Preventing the fast nonlinear controller execution, especially close to the sliding manifold, also alleviates the chattering phenomena effectively, which is a primal drawback, and limits the usage of the controller on various systems. The method’s efficiency is verified with the hardware-in-the-loop system, where the dynamic and robustness of the triggering approach are compared to the standard time-triggered execution technique.
Ključne besede: event triggering, sliding mode control, super-twisted controller, chattering alleviation
Objavljeno v DKUM: 07.12.2023; Ogledov: 268; Prenosov: 9
.pdf Celotno besedilo (2,52 MB)
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Pantograph driven with a linear induction motor with adaptive fuzzy control
Costica Nituca, Gabriel Chiriac, 2019, izvirni znanstveni članek

Opis: This article presents an adaptive fuzzy control for a linear induction motor, which is used to control the vertical movement of a pantograph, which supplies an electric locomotive from a contact line. The system has the goal of eliminating all the discontinuity on the route, the resonance phenomenon, the separation of the pantograph head from the contact wire, and electric arches. The simulations demonstrate functional control of the pantograph driven with a linear induction motor system using fuzzy control techniques.
Ključne besede: linear induction motor, fuzzy control, locomotive pantograph, simulation
Objavljeno v DKUM: 05.12.2023; Ogledov: 186; Prenosov: 3
.pdf Celotno besedilo (1,04 MB)
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Optimal control of gain and offset in direct conversion receivers : magistrsko delo
Amadej Maurič, 2023, magistrsko delo

Opis: In the master’s thesis, the development and implementation of optimal control for direct conversion receiver is presented. A background overview of direct conversion receivers, in-phase and quadrature mixers, sampling theory, control theories, adaptive systems, and optimal control is given. The development of a system model which is later used in simulations is also presented. Optimal control is achieved through standard control techniques, such as feedback and feedforward control, with error functions giving restrictions. Information to feed the optimal control is acquired by the system through the analog converters to the digital converters, digital to analog converters, and received signal strength indicators. For the development and testing of optimal control, MATLAB environment was used. Simulations and presentation of the results were also done in MATLAB. Limitations, exact operation, and comments were given throughout the thesis
Ključne besede: optimal control, direct conversion receiver, radio frequency signal, simulation, MATLAB
Objavljeno v DKUM: 23.11.2023; Ogledov: 290; Prenosov: 0

Off-design flow analysis of cogeneration steam turbine with real process data
Dušan Strušnik, Igor Kuštrin, Jurij Avsec, 2022, izvirni znanstveni članek

Opis: This paper presents the concept of reconstruction of the existing coal-fired combined heat and power plant to comply with new European environmental policies. The existing coal-fired boiler will be replaced by two new dual pressure heat recovery steam generators, which will utilize the exhaust gas heat from two new gas turbines. The steam from the heat recovery steam generators will be fed to the existing steam turbine. After the reconstruction, the nominal turbine inlet steam mass-flow of 40 kg/s will be reduced to 30 kg/s. During periods of low heat demand, only one gas turbine and one heat recovery steam generator will be in operation and the live steam mass-flow may drop even to 12 kg/s. Prior to the reconstruction, dedicated tests of the existing steam turbine were carried out using the steam from the existing coal-fired boiler. The goal of the test was to verify the viability of operation with such an extremely low mass-flow. The results of tests show that such operation is possible but inefficient from a power generation point of view. Besides this, the turbine control algorithm needs to be accommodated to this extreme operating regime and additional measures like displacement of the extraction points and steam cooling will be required to control the temperature of the steam extractions. The novelty of this paper is using real prereconstruction process data for the assessment of feasibility and efficiency of the post-reconstruction operation of a combined heat and power turbine.
Ključne besede: cogeneration, control valves, exhaust gas, heat recovery, steam turbine
Objavljeno v DKUM: 30.10.2023; Ogledov: 143; Prenosov: 11
.pdf Celotno besedilo (2,18 MB)
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Spatial clusters of Varroa destructor control strategies in Europe
Robert Brodschneider, Johannes Schlagbauer, Iliyana Arakelyan, Aleš Gregorc, 2022, izvirni znanstveni članek

Opis: Beekeepers have various options to control the parasitic mite Varroa destructor in honey bee colonies, but no empirical data are available on the methods they apply in practice. We surveyed 28,409 beekeepers maintaining 507,641 colonies in 30 European countries concerning Varroa control methods. The set of 19 different Varroa diagnosis and control measures was taken from the annual COLOSS questionnaire on honey bee colony losses. The most frequent activities were monitoring of Varroa infestations, drone brood removal, various oxalic acid applications and formic acid applications. Correspondence analysis and hierarchical clustering on principal components showed that six Varroa control options (not necessarily the most used ones) significantly contribute to defining three distinctive clusters of countries in terms of Varroa control in Europe. Cluster I (eight Western European countries) is characterized by use of amitraz strips. Cluster II comprises 15 countries from Scandinavia, the Baltics, and Central-Southern Europe. This cluster is characterized by long-term formic acid treatments. Cluster III is characterized by dominant usage of amitraz fumigation and formed by seven Eastern European countries. The median number of different treatments applied per beekeeper was lowest in cluster III. Based on estimation of colony numbers in included countries, we extrapolated the proportions of colonies treated with different methods in Europe. This suggests that circa 62% of colonies in Europe are treated with amitraz, followed by oxalic acid for the next largest percentage of colonies. We discuss possible factors determining the choice of Varroa control measures in the different clusters.
Ključne besede: Apis mellifera, COLOSS, beekeeping, acaricide, varroa control, survey results
Objavljeno v DKUM: 18.08.2023; Ogledov: 716; Prenosov: 26
.pdf Celotno besedilo (2,17 MB)
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