USAGE OF FREQUENCY LOCKED LOOP FOR TIME-DIGITAL FILTERING AND OTHER APPLICATIONS

TITLE
USAGE OF FREQUENCY LOCKED LOOP FOR TIME-DIGITAL FILTERING AND OTHER APPLICATIONS

AUTHOR(S)
Djurdje M. Perišić, Aleksandar Žorić 

ABSTRACT
This article describes development, analysis, application, and simulation of a recursive Time Frequency Locked Loop (TFLL) based on the measurement and processing of the periods of the input and output signals. TFLL is a linear discrete system of the second order, which regulates its output once per the input period. The parameters of TFLL are determined by
the ratios of clock frequencies which have to be in the predefined relationships for the stable functioning of TFLL. Mathematical description, analysis of stability conditions and properties of TFLL are performed using Z transform. The relations of the parameters which correspond to the specific applications are analyzed. Using mathematical analyses and
simulations, it is shown that TFLL is suitable for powerful noise rejection, for the different predicting and tracking applications, for the measurements of the frequency, for the filtering of impulse signal periods as well as for the other usual applications of FLL. Special emphasis is given to the development of a Time digital filter based on TFLL, using the theory of digital filters and the Mat-lab tools intended for digital filters

DOI
http://www.doi.org/10.70456/SCJW8947

PAGES
69-74

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https://unitechsp.tugab.bg/images/2023/2-EST/s2_p8_v4.pdff

How to cite this article:
Djurdje M. Perišić, Aleksandar Žorić , USAGE OF FREQUENCY LOCKED LOOP FOR TIME-DIGITAL FILTERING AND OTHER APPLICATIONS, UNITECH – SELECTED PAPERS - 2024 , 69-74

DETECTION AND ISOLATION OF A MULTIPLICATIVE FAULT IN A WIRELESS POWER TRANSFER SYSTEM

TITLE
DETECTION AND ISOLATION OF A MULTIPLICATIVE FAULT IN A WIRELESS POWER TRANSFER SYSTEM

AUTHOR(S)
Dejan Janjic, Sanja Antic, Branko Koprivica

ABSTRACT
The experimental procedure presented in the paper focuses on detecting and isolating the multiplicative fault of the compensating capacitor which can occur due to certain application conditions, on a wireless energy transfer system model. The testing was conducted on a laboratory system, which involved measuring changes in voltages and currents based on the change in the compensating capacitor's value (simulating a fault). The results obtained from the efficiency curve at the resonant frequency for different compensating capacitor values were used to detect and isolate the multiplicative fault. Additionally, the same curve was used in the approximate fault identification process, which involved determining the fault's size.

DOI
www.doi.org/10.70456/PAFI7540

PAGES
60-66

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https://unitechsp.tugab.bg/images/2023/1-EE/s1_p164_v1.pdf

How to cite this article:
Dejan Janjic, Sanja Antic, Branko Koprivica, DETECTION AND ISOLATION OF A MULTIPLICATIVE FAULT IN A WIRELESS POWER TRANSFER SYSTEM, UNITECH – SELECTED PAPERS - 2024 , 60-66

INCREASING THE EFFICIENCY OF A SHIP'S AIR-CONDITIONING SYSTEM USING SYNCHRONOUS JET MOTORS

TITLE
INCREASING THE EFFICIENCY OF A SHIP'S AIR-CONDITIONING SYSTEM USING SYNCHRONOUS JET MOTORS

AUTHOR(S)
Plamen Parushev, Ginka Ivanova, Iliyan Donev 

ABSTRACT
The article presents a study of the replacement of asynchronous electric motors with synchronous jet electric motors and an evaluation of the efficiency of a ship's air conditioning system in energy consumption modes. The balance of passenger ship electricity required to control the climate system for ventilation, cooling and heating is analyzed. The assessment was carried out in terms of fuel oil consumption and CO2 emissions. The partial distribution of the energy of the cooling system and the total consumed energy of the ship are considered. Data from real measurements are presented. The amount of energy saved by the proposal to replace the type of electric motors is calculated.

DOI
www.doi.org/10.70456/GXJC1775

PAGES
50-53

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https://unitechsp.tugab.bg/images/2023/1-EE/s1_p80_v1.pdf

How to cite this article:
Plamen Parushev, Ginka Ivanova, Iliyan Donev ,INCREASING THE EFFICIENCY OF A SHIP'S AIR-CONDITIONING SYSTEM USING SYNCHRONOUS JET MOTORS, UNITECH – SELECTED PAPERS - 2024, 50-53

SAFETY OF THE USE OF ULTRAVIOLET BACTERICIDAL LED LAMPS

TITLE
SAFETY OF THE USE OF ULTRAVIOLET BACTERICIDAL LED LAMPS

ABSTRACT

Given the rapid development of technologies in the field of ultraviolet LEDs, there was a need for their detailed research, especially their impact on the human body. The paper analyzes the state of the field of bactericidal radiation using ultraviolet LEDs. Special attention was paid to the photobiological safety of ultraviolet radiation. As a result of a theoretical study, general recommendations for bactericidal installations with ultraviolet LEDs were determined. Keywords: ultraviolet, bactericidal installations, LEDs, blue light safety, photobiological safety.


AUTHOR(S)
Pylyp Hovorov, Anastasiia Kindinova

DOI
www.doi.org/10.70456/ANDL1725

PAGES
38-44

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https://unitechsp.tugab.bg/images/2023/1-EE/s1_p60_v1.pdf

How to cite this article:
Pylyp Hovorov, Anastasiia Kindinova, SAFETY OF THE USE OF ULTRAVIOLET BACTERICIDAL LED LAMPS, UNITECH – SELECTED PAPERS - 2024 , 38-44

DESIGN OF 20MW PHOTOVOLTAIC POWER PLANT OSLOMEJ IN NORTH MACEDONIA

TITLE
DESIGN OF 20MW PHOTOVOLTAIC POWER PLANT OSLOMEJ IN NORTH MACEDONIA

AUTHOR(S)
Elizabeta Arsova, Plamen Tsankov 

ABSTRACT
North Macedonia has a good location and climate, with a large number of sunny days a year. Solar radiation ranges from 1 168 kWh/m2 to 1 650 kWh/m2 , but the sun, as a renewable and never-ending source of energy, especially to produce electricity, is unfortunately the least used. This paper presents the planning and construction of a new photovoltaic power plant PvPP Oslomej with an installed capacity of 20 MW. The location was chosen close to the Oslomej thermal power plant with an installed capacity of 125 MW. The distance of PvPP Oslomej from TS 110/35/10 Oslomej kV/kV/kV is up to 5 km, and the land is in state property, so JSC ESM Macedonia can easily take it over since this largest producer in RN Macedonia is in state ownership property. The calculations obtained using the PVsyst software are presented. The most suitable type of panels and inverters that are available on the market in RN Macedonia are selected. The orientation of the panels is east-west. That is, half of the panels will be placed towards the east and the other half towards the west. At the same time, the most favorable angle towards the sun will be chosen, which would make the most of the sun's energy during the day. In this way, PvPP Oslomej with 20 MW, would produce the largest amount of electricity. With the construction of the PvPP Oslomej with 20 MW, the Thermal Power Plant, Oslomej which uses very low caloric value coal from the nearby Oslomej mine, would be phased out. By implementing renewable energy sources, the environment will be protected.

DOI
www.doi.org/10.70456/CUER3352

PAGES
34-37

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https://unitechsp.tugab.bg/images/2023/1-EE/s1_p45_v3.pdf

How to cite this article:
Elizabeta Arsova, Plamen Tsankov, DESIGN OF 20MW PHOTOVOLTAIC POWER PLANT OSLOMEJ IN NORTH MACEDONIA, UNITECH – SELECTED PAPERS - 2024, 34-37