Maciej Zajkowski

Prof. Maciej Zajkowski

Department of Electrical Engineering, Bialystok University of Technology, 15-351 Bialystok, Poland
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Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 March 2021 in Energies
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ZSZbigniew Sołjan
Zbigniew Sołjan
GHGrzegorz Holdynski
Grzegorz Holdynski
Maciej ZajkowskiMaciej Zajkowski
Maciej Zajkowski
The article presents the possibility of using the currents’ physical components (CPC) theory to generate the reference current of the active power filter (APF). The solution proposed by the authors is based on the cooperation of minimizing balancing compensators (MBC), which, due to their use in 4-wire systems, have been divided into two structures. The first compensator, which purpose is to minimize and balance the reactive current and the unbalanced current of the zero sequence, is built in the star system (STAR-MBC). The purpose of the second compensator, which operation occurs in the delta system (DELTA-MBC), is to minimize and balance the other two components, i.e., the unbalanced current of the negative sequence and the unbalanced current of the positive sequence. The two structures cooperating with each other significantly reduce the currents associated with the reactive elements, i.e., reactive current, and the unbalanced current. As mentioned, these currents are reduced but not compensated to zero or to the reference value. In order for the compensation and balancing to bring the preferable effect, an APF system should be included, which will cooperate with MBC compensators. This solution is presented in this publication. The control of the active part of the hybrid active power filter (HAPF), which was presented in the paper, consists of the reflection of the waveform of the nonsinusoidal active current. In this approach, no current shift in relation to voltage is obtained, but the waveforms of these quantities remain distorted. The reactive current is compensated and the unbalanced currents are balanced. The second definition of generating a reference current can also be used. Through this approach, the active current with a sinusoidal waveform is achieved. The second approach allows for an additional reduction of the three-phase RMS value of the load’s current. In both of these approaches, the active currents flowing through the lines will reflect the amplitude and phase asymmetry that is present in the supply voltage. The APF system will follow the changes in power or load conditions and generate the correct value for the reference current. The calculations presented in the article, as well as the current and voltage waveforms, were created as a result of the constructed mathematical models, which were used for theoretical illustrations. Calculations and waveforms were generated based on a script written in Matlab.

7 November 2022 in Energies
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ZSZbigniew Sołjan
Zbigniew Sołjan
Maciej ZajkowskiMaciej Zajkowski
Maciej Zajkowski
In 1927, the most recognized power theory in the frequency domain was proposed by Budeanu. The second power theory in the frequency domain, which is currently catching a lot of supporters, is the approach proposed by Czarnecki. Both theories have common features in the form of the description of active power and are completely different in terms of the description and interpretation of reactive power. This article presents the possibility of using mutual elements of both approaches: thus, it is possible to interpret the physical meaning of the reactive power (reactive current) proposed by Budeanu and the power before the deformation obtained from the mathematical description.

31 December 2023 in Energies
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ZSZbigniew Sołjan
Zbigniew Sołjan
Maciej ZajkowskiMaciej Zajkowski
Maciej Zajkowski
Andrzej BorusiewiczAndrzej Borusiewicz
Andrzej Borusiewicz
This article presents methods of reactive power compensation using passive elements in the form of a capacitor (C) or choke (L) and an LC structure selected in such a way as to lead to the minimization of the reactive current (reactive power) of a single-phase system. The adaptation of the parameters of a passive compensator, reducing reactive power and/or distortion power, was possible through the extended Budeanu theory. In addition, through the extended Budeanu theory and also through the knowledge of the equivalent parameters of the linear load, the obtained results of the increase in distortion power, depending on the structure of the passive compensator, were analyzed. The values listed in the tables, as well as the waveforms of the component currents of a single-phase linear load, were obtained based on calculations and simulation models in MATLAB/Simulink software R2023a.

25 July 2022 in Energies
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MKMarek Kurkowski
Marek Kurkowski
Tomasz PoplawskiTomasz Poplawski
Tomasz Poplawski
Maciej ZajkowskiMaciej Zajkowski
Maciej Zajkowski
BKBartosz Kurkowski
Bartosz Kurkowski
MSMichał Szota
Michał Szota
According to various estimates, street lighting in Poland consumes between 1.500 and 2.500 GWh per year and is responsible for some greenhouse gas emissions from electricity generation. Also on the basis of estimates, it is estimated that approximately 3.3 million road and street luminaires are used in Poland. The increase in electricity costs, on the one hand, and the technical possibilities in the field of lighting, on the other, force the search for new solutions aimed at saving during the operation of electrical devices and installations, including road lighting installations. One of the methods of saving electricity is to replace the luminaires with energy-saving ones with LED sources, but also with new sodium and metal halide sources. The latter solution is cheaper and allows us to keep existing poles, electrical installation and luminaire heads if their technical parameters have not been degraded. The new and already used luminaires with discharge sources can be used in road lighting, provided that they meet the requirements of Polish law and the EU regulations. Like luminaires with LED sources, they can have an adjustable value of the emitted luminous flux, which allows us to save electricity. One of the methods of saving electricity in road installations is their effective lighting control. Such control can take place at very different levels, from the manual setting of the required light intensity using dimmers to full automation taking into account other factors influencing the operation of the road lighting system, e.g., time of day, intensity of external light, presence of road users, weather conditions and others. The article describes both of the above-mentioned methods, describing their advantages and disadvantages on the basis of actual measurements of working road installations, and analyzes the annual operation of a modernized road lighting installation with automatic lighting control in one of the selected cities in Poland.

3 January 2023 in Energies
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HSHonorata Sierocka
Honorata Sierocka
Maciej ZajkowskiMaciej Zajkowski
Maciej Zajkowski
GHGrzegorz Holdynski
Grzegorz Holdynski
ZSZbigniew Sołjan
Zbigniew Sołjan
The article presents the results of the analysis of parameters describing electricity consumption in individual phases of the production cycle on a poultry farm. One full broiler rearing cycle on the farm was analyzed. Electrical parameters were tested during the broiler rearing process using a power quality analyzer with a measurement interval of 1 min. During the tests, the analyzer recorded the active and reactive power, phase and line voltage, power factor, and frequency. On the basis of collected data, original indicators describing electricity consumption per chicken wkA, wkQ, and per unit area wiA, wiQ were determined. The regression curves of active and reactive power consumption in particular stages of the cycle were also determined, and the minimum and maximum values of active and reactive power consumption were determined. The accomplished research can be used in planning electricity demand in energy-self-sufficient areas. The presented original indicators can be used to determine power demand on broiler farms, depending on the planned production volume or size of farm buildings.

30 November 2023 in Applied Sciences
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ŁGŁukasz Gryko
Łukasz Gryko
Urszula Joanna BłaszczakUrszula Joanna Błaszczak
Urszula Joanna Błaszczak
Maciej ZajkowskiMaciej Zajkowski
Maciej Zajkowski
Disinfection and sterilization based on the use of UVC radiation are the key technologies ensuring health and safety. Their reliability depends on assuring the effectiveness of the performed process. In recent years, the rapid development of LED sources emitting high-power radiation in the UVC range has been observed, and there is a growing interest in using them in a variety of smart applications, mostly because they are easy to control, do not contain hazardous substances, and there are prospects to increase their energy efficiency. However, the literature does not provide enough knowledge on the reliability of disinfection with high-power UVC LEDs. This research aims to present a methodology of linking the performance characteristics with assessing the forecasted changes in the disinfection efficiency of exemplary UVC high-power LEDs caused by thermal and temporal changes in their characteristics. Based on the performed degradation test, the impact of the temperature and time of operation of the high-power UVC LEDs on the effectiveness of disinfection was evaluated, and the required disinfection times for exemplary pathogens were calculated. The results reveal a strong influence of the time of operation of high-power UVC LEDs on the disinfection reliability caused by the degradation of their optical power but with a low significance of wavelength shift.