| Working Modes of a Transformer |
| Simona Filipova-Petrakieva |
|
Abstract: The main function of the transformer is to convert AC voltage from one value to another. Its normal working mode is to increase or decrease the AC voltage. When its primary and secondary windings have equal turns, it is used to galvanically separate of the consumer from the power supply. Depending on the connection of the secondary winding to the load, it works in modes of increasing or decreasing the output voltage - booster or buck transformer, respectively. In these modes, the design of the transformer ensures less power than in normal use. It is absolutely forbidden to connect the primary and secondary windings to the power supply in parallel each other and in parallel of the supplied voltage without reactive passive elements in series of them. This is only possible for primary and secondary windings with equal number of turns. In the present work, a detailed analysis of these modes is provided. The stress is on their specific character. Keywords: working modes of transformer – accepted and unaccepted, booster transformer, buck transformer |
| DOI: 10.47978/TUS.2024.74.02.001 |
| Analysis of Innovative Methods for Forming Voids in High Pressure Castings |
| Ivan Ivanov |
Abstract: The study is about some promising and innovative methods giving new possibilities for the application of the high pressure casting process. The main goal is to evaluate the possibilities of the considered methods for their application in the production of details for the automotive industry. This type of detail is characterized by a complex shape and high quality requirements. The industry itself requires them to be increasingly complex and sophisticated, which places new tasks on technological processes and methods. The need to make a part that combines the functions of several requires it to have closed cavities - surfaces and elements of geometry that cannot be formed with traditional permanent forms. The construction of such tools usually provides for removal by means of mechanically driven elements, which in almost all cases have a rectilinear movement. This, in turn, drastically limits the possibilities regarding the complexity of the shaded area. Another object of the methods is to obtain castings that have internal channels for transfer of working pressure or tempering hydraulic fluid. Keywords: High Pressure Die Casting, Dies, castings, aluminum alloys, molded-in-inserts, shaded areas, channels of complex shape, automotive industry, electric vehicles, batteries, salt cores |
| DOI: 10.47978/TUS.2024.74.02.002 |
| Digital Entities and the Concept of Social Life in a New Generation of Social Meeting Platforms |
| Vesselin Evgueniev Gueorguiev, Desislava Georgieva, Ivan Evgeniev Ivanov |
Abstract: The synthesis of plausible behaviour of avatars in a new generation of social meeting platforms requires solving many problems. The problems are related to the technical aspects and the social contacts goals. Existing models created for video games are not layered enough and reflect only a fraction of the tasks of a digital universe. This calls for the development and discussion of new conceptual models for digital entities, for the synthesis of their social behaviour, and the nature of interaction "user-virtual universe". The proposed paper addresses one element of a new conceptual system for synthesizing the behaviour of three-dimensional realistic social avatars in a digital universe. Keywords: AI, digital entity, meeting platform |
| DOI: 10.47978/TUS.2024.74.02.003 |
| Octave Memristor Models’ Library and Application for Analysis of Memristors and Memristor-Based Circuits |
| Stoyan M. Kirilov |
Abstract: Memristors are favorable electronic components with decent switching and memory features. Owing to their low energy usage, nano-scale sizes, and sound compatibility with present CMOS high-density integrated schemes, memristors are potentially applicable in neural nets, memory arrays, and different reconfigurable microelectronic devices. Design and analysis of memristor elements and circuits, based on memristors with electronic simulators is very important task. This paper presents modelling and investigations of single memristors and several humble memristor-based circuits in GNU Octave, applying some analytical and numerical solutions. The suggested work could be valuable for educational and scientific goals. Additional analyses are made in LTSPICE for confirmation the proper action of considered memristor circuits with high efficiency. During the analyses, several modified and standard memristive models are utilized and compared. Design of new electronic circuits based on nano-electronic elements is an important step towards generation of very high-density integrated circuits. Keywords: GNU Octave software, finite differences method, LTSPICE environment, numerical modeling |
| DOI: 10.47978/TUS.2024.74.02.004 |
| Distributed RTOS Microkernel for Multicore ARM-based Control Systems |
| Ivan Evgeniev Ivanov, Alexander Hotmar, Martin Minkov, Vesselin Evgueniev Gueorguiev, Desislava Georgieva |
Abstract: We are seeing an ever-increasing amount of real-time systems. Many of these are embedded in a variety of field devices requiring significant amounts of computation. Others are connected to a large number of sensors and actuators. The characteristic of all of them is that even the available increased performance of modern processors designed for embedded applications does not always meet the requirements. In this case, the switch is to processors with many cores. Real-time control of computational processes in multicore systems is a task of non-trivial complexity. The paper presented here discusses some aspects of the implementation of the RTOS microkernel for ARM-based multicore control systems. Keywords: RTOS, distributed kernel, multicore ARM |
| DOI: 10.47978/TUS.2024.74.02.005 |
| Overview of the Management of Micro Grids with Renewable Energy Sources |
| Peyu Pasev, Nikolina Petkova, Valeri Mladenov |
Abstract: We are seeing an ever-increasing amount of real-time systems. Many of these are embedded in a variety of field devices requiring significant amounts of computation. Others are connected to a large number of sensors and actuators. The characteristic of all of them is that even the available increased performance of modern processors designed for embedded applications does not always meet the requirements. In this case, the switch is to processors with many cores. Real-time control of computational processes in multicore systems is a task of non-trivial complexity. The paper presented here discusses some aspects of the implementation of the RTOS microkernel for ARM-based multicore control systems. Keywords: Distributed power generation, Energy storage, Microgrids, Photovoltaic effects, Photoelectricity |
| DOI: 10.47978/TUS.2024.74.02.006 |
| Algorithm for Payment with POS Terminals in Real Time |
| T.Pavlov, J.Ostrev, A.Marinchev, V.Galabov |
Abstract: In recent years, real-time payments with POS terminals have increased and their application is ubiquitous (for example at 2022 they are about 77.4 million per hour). Paying with POS terminals is also a convenience, which is a preferred way of transferring amounts in electronic form. Bank transaction information is related to the transfer amount, bank card type, card issuer, card type, transaction type and many other parameters. POS terminals are often operated in more than one or two shifts per day. Existing algorithms for POS terminals offer functionality, only for the most important minimum amount of data for preparing accounting documents. Very often POS terminals are used with cash registers (Cash Register). In these cases, automated data processing usually exists and data reporting is facilitated, and when not, addition is relatively easier compared to adding the functionality directly to the POS terminal software. The proposed algorithm does not require the presence of a cash register and provides the opportunity to receive detailed reporting in a pre-selected period of time by the user. Keywords: payments, POS terminals |
| DOI: 10.47978/TUS.2024.74.02.007 |