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Number of results: 9
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Abstract

In the paper selected methods of measuring the thermal resistance of an IGBT (Insulated Gate Bipolar Transistor) are presented and the accuracy of these methods is analysed. The analysis of the measurement error is performed and operating conditions of the considered device, at which each measurement method assures the least measuring error, are pointed out. Theoretical considerations are illustrated with some results of measurements and calculations.
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Authors and Affiliations

Krzysztof Górecki
Paweł Górecki
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Abstract

The one-dimension frequency analysis based on DFT (Discrete FT) is sufficient in many cases in detecting power disturbances and evaluating power quality (PQ). To illustrate in a more comprehensive manner the character of the signal, time-frequency analyses are performed. The most common known time-frequency representations (TFR) are spectrogram (SPEC) and Gabor Transform (GT). However, the method has a relatively low time-frequency resolution. The other TFR: Discreet Dyadic Wavelet Transform (DDWT), Smoothed Pseudo Wigner-Ville Distribution (SPWVD) and new Gabor-Wigner Transform (GWT) are described in the paper. The main features of the transforms, on the basis of testing signals, are presented.

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Authors and Affiliations

Janusz Mroczka
Mirosław Szmajda
Krzysztof Górecki
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Abstract

In the paper the problem of modelling thermal properties of semiconductor devices with the use of compact models is presented. This class of models is defined and their development over the past dozens of years is described. Possibilities of modelling thermal phenomena both in discrete semiconductor devices, monolithic integrated circuits, power modules and selected electronic circuits are presented. The problem of the usefulness range of compact thermal models in the analysis of electronic elements and circuits is discussed on the basis of investigations performed in Gdynia Maritime University.

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Authors and Affiliations

Krzysztof Górecki
Janusz Zarębski
Paweł Górecki
Przemysław Ptak
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Abstract

This paper describes the study of thermal properties of packages of silicon carbide Schottky diodes. In the paper the packaging process of Schottky diodes, the measuring method of thermal parameters, as well as the results of measurements are presented. The measured waveforms of transient thermal impedance of the examined diodes are compared with the waveforms of this parameter measured for commercially available Schottky diodes.

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Authors and Affiliations

Damian Bisewski
Marcin Myśliwiec
Krzysztof Górecki
Ryszard Kisiel
Janusz Zarębski
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Abstract

The variability of the mean annual air temperature and precipitation totals in three periods: 1848–2010, 1951–2010 and 1981–2010 was investigated in the large Warta River basin, being the area with lowest rainfall in Poland. For the purposes of research, nine meteorological stations with the longest measurement series were selected. Air temperature increase in this river basin was similar than in neighbouring countries. In the last 30 years this trend kept increasing. The precipitation in the whole studied period was slightly increasing in the northern part of the Warta River basin, but decreasing in the southern part. The mean annual precipitation totals in the catchment area did not change visible. In the period 1981–2010, the precipitation totals show a small increase in the winter and spring and a decrease in summer. A negative influence of this climate change was not visible in the Warta River discharge. The main objectives of this study were the collection long-term records of air temperature and precipitation in the Warta River basin, and the statistical analysis of climate variability.

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Authors and Affiliations

Piotr Ilnicki
Ryszard Farat
Krzysztof Górecki
ORCID: ORCID
Piotr Lewandowski
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Abstract

The paper presents a simple method of measuring the luminous flux value dedicated to LED light sources. This method uses information about a spatial radiation pattern of the lighting source under test and the results of illuminance measurements at the axis of this source. The method is described and the results of the measurements obtained using this method and the classical method are compared and discussed. Tests have been carried out for LED modules of different geometries. The measurement error of the considered method is analysed.
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Authors and Affiliations

Krzysztof Górecki
1
ORCID: ORCID
Aleksandra Kalinowska
2
Przemysław Ptak
1
ORCID: ORCID

  1. Department of Marine Electronics, Gdynia Maritime University, ul. Morska 81-87, 81-225 Gdynia, Poland
  2. Faculty of Electrical Engineering, Gdynia Maritime University, ul. Morska 81-87, 81-225 Gdynia, Poland

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