P1 – Circuit model of E – plane third – order bandstop waveguide filter, Ana TATOVIĆ, Milka POTREBIĆ IVANIŠ and Milan PLAZINIĆ

This paper presents a novel circuit model of E –plane third – order bandstop filter. The bandstop filter consists of half-wave resonators (HWRs) which are printed on a thin dielectric substrate to form an insert positioned in the E-plane of a rectangular waveguide. Utilization of the proposed circuit model enables faster fine-tuning design, thus the time consuption is reduced, in comparison with the duration of repeated simulations and memory consuming three-dimensional electromagnetic (3D EM) simulations. Filter is designed for the center frequency of 11 GHz and fractional bandwidth (FBW) of 2.87%.

P2 – Influence of bi-isotropy on electric potential and field distribution of prolate rotational ellipsoid in a homogeneous axial electric field, Zlata CVETKOVIĆ, Žaklina MANČIĆ, Bojana PETKOVIĆ and Nikola SIMIĆ

Investigation of an influence of the homogeneous electric field on bi-isotropic molecules is very important in order to ensure the success of the electroporation process. The values of bi-isotropic parameters affect differently the distribution of electric and magnetic scalar potential and field, depending on the degree of elongation of a prolate rotational ellipsoid, by which a molecule has been modelled. This paper gives a quantitative analysis of an impact of a level of bi-isotropy on the constants appearing in expressions for potential and field inside and outside an ellipsoid.

P3 – Impact of dust on the performance of monocrystalline solar photovoltaic (Pv) systems, Simona ILIE, Adrian MAGHET, Ildiko TATAI, Oana MARES and Dejan IOVANOVIC

One way to reduce harmful emissions into the atmosphere caused by the burning of fossil fuels for production of electricity, is to use as much as possible renewable primary energy sources, mainly, solar energy. This paper presents an experimental model of a monocrystalline solar photovoltaic system that is analysed under clear and dusty conditions in the same setup. The experimental model analyzes the parameters that influence the overall efficiency of a power plant.

P4 – Dynamic model of permanent magnet synchronous motor with included losses, Venco ĆORLUKA and Željko HEDERIĆ

Synchronous motor losses are divided into the following groups: mechanical losses (friction ventilation losses); iron losses; additional losses; stator copper losses. Mechanical losses occur due to bearing friction, rotor ventilation, fan ventilation and cooling pump. These losses are constant at constant speed and they vary proportionally to the change in speed. Iron losses occur due to changes in the magnetic field in the stator and rotor cores. They are divided into eddy current losses and hysteresis losses. Hysteresis losses are due to the appearance of a hysteresis loop in the core. Eddy current losses are due to induced currents in the core material, which are conductors of electric current after all. Additional load occurs due to armature reaction, flux leakage and mechanical imperfections of the motor. Copper losses occur due to current flow through the winding. It slightly increases with load due to the skin effect and eddy currents in the winding.

P5 – Analysis of thermal distribution of hot leak spots on heat underground pipeline, Dejan BLAGOJEVIĆ, Srđan JOVKOVIĆ, Milan PROTIĆ and Nikola MILUTINOVIĆ

Damage to underground pipelines is a serious problem that can have a significant impact on both the environment and the economy. It is important to take steps to reduce the risk of damage, such as using corrosion-resistant materials and conducting regular inspections.The analysis of thermal distribution of hot leak spots on underground pipelines involves studying the temperature patterns and distribution around areas where a leak or hot spot has occurred. This analysis is important for identifying and mitigating potential risks, such as structural damage, safety hazards, or environmental impacts. In this paper, the analysis of the thermal distribution of the thermal installation of the PUC Niska Toplana is the purpose of creating a platform for predicting faults resulting from pipe damage. The recording was performed using the ZENMUSE 20HT camera, which was attached to the unmanned aircraft MATRICE 300 RTK, while the analysis was conducted in the Dja Thermal Tools 3 programming environment. The obtained results need to indicate clear correlation and justification a thermal distribution function analysis from the tehram raditoan point of view.

P6 – Hybrid-fuzzy Takagi-Sugeno orthogonal controllers applied in the control of the tower crane system, Saša NIKOLIĆ, Nikola DANKOVIĆ, Miroslav MILOVANOVIĆ, Darko MITIĆ, Petar ĐEKIĆ, Igor KOCIĆ and Marko ŽIVKOVIĆ

The main idea of this paper is to present a possibility of application of hybrid-fuzzy controllers in control systems theory. In this paper, we have proposed a new method оf using generalized orthogonal Malmquist polynomials, i.e., Müntz polynomials in control of complex industrial systems. These functions are used in the concluding phase of the fuzzy controllers. Proposed hybrid-fuzzy Takagi-Sugeno orthogonal controllers has been applied to a tower crane system and performed experiments have verified efficiency and improvements of a new control method.

P7 – Validation of distributed energy resources in accordance with voltage fluctuation limitations prescribed by the IEEE 1547-2018 standard, Marko DIMITRIJEVIĆ and Milutin PETRONIJEVIĆ

The increased need for clean energy and global warming are among the biggest challenges of the modern age. One of the potential solutions to these challenges, which can be achieved by using existing technologies, are distributed energy resources (DER). DER can be an isolated system of different capacity and purpose, but in most cases, it is connected to the electricity grid. Connecting a DER system to the electricity grid is a complex task, which complexity increases with the number of integrated DERs. In order to regulate interoperability and interconnection of DERs with electricity grid, the IEEE 1547-2018 standard is imposed. Among other requirements, the standard prescribes voltage fluctuation limitations induced by the DER. The analysis of voltage fluctuations – flicker assumes measurement procedures defined by IEEE 1453-2015 standard and implementation of digital flicker-meter described by IEC 61000-4-15 standard. In this proceeding, the realization of virtual instrument for voltage fluctuation analysis will be presented. This function is part of more comprehensive system for DER validation.

P8 – Statistical considerations on high-frequency radiation patterns caused by power drive systems, Ana VUČKOVIĆ and Bernd JAEKEL

Limits for high frequency radiated emissions from electrical equipment have been specified for many decades already. Though the main reason for the limits is the protection of radio services which parameters are well known, in many cases the technical background or the justification for the derivation of those limits is not known or has not been described and published. To overcome this situation, in particular when being faced with the work on new limits, a probabilistic approach has been developed in the standardisation document CISPR TR 16-4-4 which is intended to be used for the derivation of limits. This paper describes the process of deriving such limits for a particular type of equipment, i.e. power drive systems, and for a particular probability factor which considers the directivity. It focuses on a probabilistic approach with respect to the radiation pattern caused by such equipment. 

P9 – Investigating the effects of glasses on electric field distribution from a mobile phone inside the human eye during web surfing, Dejan JOVANOVIĆ, Vladimir STANKOVIĆ, Nenad CVETKOVIĆ, Dragana ŽIVALJEVIĆ and Dragan VUČKOVIĆ

This paper discusses the effects of the glasses exposed to electromagnetic radiation from mobile phones on the electric field distribution inside the human eye. The numerical analysis has been performed for the case when the mobile phone is used for web surfing at the frequency of 2.6 GHz. Obtained results are presented within different biological tissues from which the human eye model was made. Since the human body consists of various tissues and organs, each needs to be described in terms of its corresponding electromagnetic properties. A realistic 3D model of the human head has been created to obtain the most accurate results. The main aim of this investigation is to determine the electric field distribution in the human eye. For this research, besides the realistic model of a human head, it was necessary to develop a realistic eye model formed of nine different tissues and a model of glasses with a metal frame. A comparative analysis of the model behaviour with and without glasses has been carried out to evaluate the effects of the glasses with metal frame. Finally, the paper presents the results of electric field distribution for a horizontal cross-section of the human head model.

P10 – Characteristic parameters determination of circular-shaped microshield lines, Mirjana PERIĆ, Saša S. ILIĆ, Natalija IVKOVIĆ and Isidora JOVANOVIĆ

Hybrid boundary element method is used to determine the characteristic parameters of circular-shaped microshield lines. The effect of different parameters on characteristic impedance is studied. Results from the proposed method are compared with those obtained using a simulation software. The results have a good agreement.

P11 – Study of the time-current characteristic of a high-power fuse in the limiting current region, Ivan HADZHIEV, Dian MALAMOV, Nikolay KOLEV, Iosko BALABOZOV and Ivan YATCHEV

This paper presents an experimental and numerical study of the thermal processes and time-current characteristic of a high-power low-voltage fuse. The tests within this study were carried out under rated current load and in the region of the limiting current. An experimental setup was developed for the purposes of the experimental tests. The temperature of the fuse was measured both by a thermovision camera and by a contact thermometer. The numerical studies were carried out by means of developed in COMSOL software 3D model of a fuse in transient mode. Results were obtained for the effect of the current load on fuse heating and actuation time. Comparison of the obtained experimental and numerical results was made.

P12 – An approximate model for determining the resistance of a hemispherical ground electrode placed at the top of the non-homogeneous truncated cone, Dragan VUČKOVIĆ, Dejan JOVANOVIĆ, Nenad CVETKOVIĆ, Miodrag STOJANOVIĆ and Dragan TASIĆ

The procedure for analysis of hemispherical ground electrode placed at the top of the hill is presented in the paper. The mountain is modeled as truncated cone of finite height, consisting of two homogeneous areas, each having different electrical characteristics. The applied approach is a combination of several recently proposed procedures. It includes application of the Estimation method and the use of an approximate expression in closed form. The obtained results are validated and compared with those obtained using the COMSOL program package.

P13 – Parameter identification and self-commissioning of the industrial drives, Bojan BANKOVIC, Filip FILIPOVIC, Nebojsa MITROVIC and Vojkan KOSTIC

The accuracy of the induction motor’s parameters identification is very important for reliable and efficient control via a frequency converter. Different approaches and methods are presented over the years, and some of them become an integral part of the converter algorithms during the self-commissioning procedures. The goal of this paper is to compare the quality of the identified parameters with converters from different manufacturers, identifying the sequence during the procedures that correspond to certain parameter of the induction motor.

P14 – Performance of uplink NOMa system with 2k+1 users, Aleksandra PANAJOТOVIĆ, Jelena ANASTASOV, Dejan MILIĆ and Daniela MILOVIĆ

In this paper, we analyse an uplink power-domain non-orthogonal multiple access (NOMA) system in which 2K+1 users are to be served. The simple user clustering scheme based on High-High/High-Low algorithm precedes the data-rate based power allocation algorithm. Channels are characterized by Fischer-Snedecor (F) composite fading model. The influence of different fading/shadowing channel conditions and various users’ positions is illustrated through the presented numerical results of outage probability and data sum rate of the considered NOMA system.

P15 – Automated approach to model-driven engineering leveraging ChatGPT and Ecore, Nenad PETROVIĆ and Issam AL-AZZONI

In this paper, we propose an automated workflow for enhancement of applications relying on model-driven engineering (MDE) approach using Eclipse Modeling Framework (EMF) and its Ecore (meta-)models. ChatGPT is leveraged for purpose of code generation in order to cover the following MDE scenarios: 1) meta-model construction based on textual data 2) model instance creation using meta-model and textual data as input 3) retrieval of specific model parameters. For implementation, we utilize Python API for ChatGPT and prompt engineering.

P16 – Low-code approach to development of AI-enabled multiplatform mobile applications relying on ChatGPT, Nenad PETROVIĆ and Valentina NEJKOVIĆ

In this paper, we propose an approach to rapid and intuitive development of multiplatform smartphone apps based on low-code frameworks – AppShet and Google Apps Script. Additionally, we incorporate the capabilities of powerful artificial intelligence thanks to ChatGPI API. Our approach is evaluaed in several scenarios: 1) gamification elements within tourism-oriented apps 2) instruction generation 3) item recommendation.

P17 – External inductance per unit length calculation of two wire lines with negligible thickness in the vicinity of linear magnetic material, Saša S. ILIĆ, Dragana VUKIĆ, Mirjana PERIĆ and Ana VUČKOVIĆ

Hybrid boundary element method is applied for the calculation of external inductance per unit length of two wire lines with negligible thickness in vicinity of a linear magnetic material. Computation is done for two cases and for different parameters values of observed system. Results obtained using the hybrid boundary element method and software package FEMM 4.2 are compared and shown in this paper.