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1
Content available Thermal investigations of PCM enhanced electronics cooling
Felczak Mariusz, Więcek Bogusław
Measurement Automation Monitoring
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2019
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Vol. 65, No. 2
44--47
EN
The paper presents experimental results of PCM (Phase Change Material) enhanced cooling system. The investigations were focused on obtaining the best results of the cooling system during its start-up. The latent heat of phase change material was used to decrease temperature of the cooled electronic device. Comparison of a standard heat sink available on the market and the same heat sink filled with PCM applications was done. Temperature was monitored and registered during device start-up until its thermal steady state. It was done using contact and IR temperature measurement methods. PCMs usage enabled to absorb heat during electronic device start-up. The paper proves that using PCMs it is possible to delay temperature rise during electronic devices heating.
2
Content available Low-cost IR system for thermal characterization of electronic devices
Kopeć M., Więcek B.
Measurement Automation Monitoring
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2018
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Vol. 64, No. 4
103--107
EN
In this article, a Low-cost measurement Infra-Red (IR) system for dynamic thermal testing of electronic devices is described. The element is powered by a step-function current and simultaneously temperature is measured by a fast single-detector IR head. The thermal impedance Zth(jω) is calculated using the Laplace transform and the Foster network is to get thermal time constants distribution.
3
Content available Various applications of complex thermal impedance for transient and AC heat transfer analysis
Więcek B., De Mey G., Strąkowska M., Chatziathanasiou V., Gmyrek Z., Strzelecki M., Chatzipanagiotou P.
Measurement Automation Monitoring
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2015
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Vol. 61, No. 6
210--214
EN
This paper presents the concept and three practical examples of using complex thermal impedance for characterisation different thermal objects. The first problem describes estimation time shift between power and temperature in electric distribution systems with non-sinusoidal currents. The second example discussed here, shows the estimation of power losses distribution in the magnetic punched ferromagnetic strips. The third application presents the inverse thermal modelling of 3-layer biomedical objects (tissues) to estimate the thermal parameters. More details of the presented problems are in the appropriate papers of the authors referenced here.
4
Content available Thermal Characterization of High-Frequency Flyback Power Transformer
Kasikowski R., Gołaszewski J., Więcek B., Farrer M.
Measurement Automation Monitoring
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2015
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Vol. 61, No. 6
237--241
EN
This paper presents preliminary thermographic measurements and a simple thermal analysis of power losses in high-frequency (H-F) transformers used in AC-DC power converters. The analysis is based on complex thermal impedance and time constant distribution. The main aim of this research was to consider quantitatively the contribution of different power losses in the H-F transformer, including fringing flux effect.
5
Content available Application of thermal impedance to inverse heat transfer modeling of power cables
Więcek B., Strąkowska M., De Mey G., Chatziathanasiou V., Chatzipanagiotou P.
Pomiary Automatyka Kontrola
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2013
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R. 59, nr 9
946--949
EN
This paper presents the inverse heat transfer modeling in applications to the power cables. In order to simplify the calculations, the inverse modeling implements thermal simulations in frequency domain. Due to the cylindrical summery of the power cable, this model has an analytical solution, which simplifies using Bessel functions. The inverse model allows estimating the thermal parameters of the material the cable is made of. It can be used for defect detection and aging of the cable. The model was made in Matlab®, and compared with the results obtained from COMSOL® simulation software.
PL
W pracy przedstawiono zastosowanie modelowania cieplnych zjawisk odwrotnych do wyznaczania wartości parametrów termicznych kabli energetycznych. W procesie modelowania odwrotnego struktury wykorzystano model w dziedzinie częstotliwości, który dla struktury o symetrii cylindrycznej ma rozwiązanie analityczne przy użyciu funkcji Bessela. Model termiczny wraz z optymalizacją opracowano w programie Matlab®. Wyniki modelowania odwrotnego zweryfikowano rezultatami uzyskanymi z symulacji 3D wykonanych za pomocą oprogramowania COMSOL® oraz za pomocą danych pomiarowych, uzyskanych z kamery termowizyjnej. Opracowana metoda może być wykorzystana w praktyce do oceny stanu kabli energetycznych, ich zużycia, do wykrywania defektów związanych np. z korozją oraz do oszacowania warunków odprowadzania ciepła z kabli do otoczenia. W konsekwencji na podstawie wyników termowizyjnych można wyuczyć wartość impedancji termicznej kabla, co pozwoli oszacować maksymalną wartość temperatury w określonych warunkach pracy. Na obecnym etapie badań wykonano model kabla z litego materiału. Kolejnym krokiem będzie opracowanie modelu kabla wielowarstwowego, w tym z izolacją o małej przewodności cieplnej.
6
Content available remote Badanie wpływu temperatury na parametry termiczne i elektryczne diod LED mocy
Kraśniewski J., Oleksy M.
Przegląd Elektrotechniczny
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2011
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R. 87, nr 10
180-182
PL
W niniejszym artykule przedstawiono wyniki pomiarów charakterystyk statycznych prądowo-napięciowych (zarówno izo- jak i nieizotermicznych) białych diod LED wysokiej mocy w różnych temperaturach otoczenia. Zaprezentowano również wyniki pomiarów przejściowej impedancji termicznej tych diod.
EN
In the following article the measurement results of static current-voltage characteristics (both iso and non-isothermal) of white powerLED are presented. Also, measurement results of thermal transient impedance of the powerLED are presented.
7
Content available The aberrations of the AC thermal characteristics in the presence of solder defects in mltilayer microelectronic structures
Gnidzińska K.
International Journal of Microelectronics and Computer Science
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2011
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Vol. 2, nr 4
156-159
EN
In this paper, the multilayer microelectronic structures have been modeled using AC thermal modeling approach. The influence of defects in solder layers on the thermal parameters of the structures has been investigated. It has been presented how an aberration in a solder layer that may result e.g. from the manufacturing flaw, can significantly affect the thermal characteristics of the structure thus aggravating the conditions of the heat transfer. The phenomena have been described in the qualitative and quantitative way. Furthermore, the applicability of the proposed modeling method for the purpose of determining the optimal frequency range in non-destructive device testing technique - lock-in thermography - has been demonstrated.
8
Content available Heat path characterization of high-k HfO2-Ta2O5 capacitor in Verilog-A
Masana F. N.
International Journal of Microelectronics and Computer Science
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2011
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Vol. 2, nr 3
100-104
EN
Thermal impedance measurement of semiconductor devices is one of the standard and well established methods of characterization. From such measurements can be obtained not only behavioral information in the form of graphs or models for thermal simulation, but also structural information about the thermal path involved, from source to sink, that can be very useful in device assembly process characterization and control. Structural information, however, usually requires many processing steps of measured data with its associated calculation burden and numerical errors. This work proposes a method to extract structural information from measured data in a straightforward way, with very few and elementary calculations, thus providing a useful analysis tool.
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