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1
Content available remote Wpływ złożoności biblioteki termicznej tranzystora IGBT w programie PLECS na dokładność wyznaczania temperatury jego wnętrza
Górecki Piotr, Bielecka Agata, Wojciechowski Daniel
Przegląd Elektrotechniczny
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2021
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R. 97, nr 2
16--19
PL
W pracy przedstawiono wpływ złożoności biblioteki termicznej tranzystora IGBT w programie PLECS na dokładność wyznaczania temperatury jego wnętrza. Przedstawiono sposób modelowania tranzystora IGBT w programie PLECS, a także sprawdzono jak należy opisywać jago właściwości statyczne by uzyskać dobrą dokładność obliczania temperatury wnętrza tego tranzystora. Wykonano obliczenia i określono wartości błędu względnego wyznaczania przyrostu temperatury wnętrza dla różnych sposobów odwzorowania jego charakterystyki wyjściowej.
EN
In the paper, an influence of complexity of a thermal library of IGBT in PLECS on the accuracy of computing its junction temperature is presented. The modeling method of IGBT in PLECS is presented, and it is also showed how to describe the static properties of the IGBT to obtain good accuracy of computing junction temperature of the transistor. Appropriate analyzes were carried out in PLECS and the relative error values of determining the IGBT junction temperature increase are determined for various manners of mapping its output characteristics.
2
Content available Comparative study of cooling of automobile LED headlights without and with fins and finding comfortable operating conditions
Mishra Manbodh Kumar, Chandramohan V. P., Balasubramanian Karthik
Archive of Mechanical Engineering
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2019
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Vol. LXVI, nr 3
295--314
EN
LED light must be cooled to avoid reaching a certain temperature. Two different 3D practical domains of LED light are modelled, (i) square aluminium plate with a cylindrical plate and an LED module (model I), (ii) the same provision of model I with 25 fins (model II). ANSYS 16.0 is used for solving the problem. Temperature distribution, junction temperature (Tj ) and heat flux are estimated. Analyses are carried out for various ambient temperatures (Ta) and for different LED power dissipations (Q) to identify the safe operating conditions. In model I, it is found that 38% of working conditions go beyond the critical limit of Tj and it is reduced to 21.4% in model II. In model II, for low Ta of 30 and 40 C with all Q considered in this analysis are safer. If Ta is between 30 and 80 C, then Q must be maintained at 0.5 to 1.25 W. Beyond this, conditions are not safe.
3
Content available remote Study of the Light Emitting Diode as a photoreceptor : spectral and electrical characterization as function of temperature and lighting source
Vannacci E., Granchi S., Cecchi M., Calzolai M., Mazzi E., Biagi E.
Opto-Electronics Review
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2018
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Vol. 26, No. 3
201--209
EN
In this study, the temperature influence on the spectral responsivity of a Light Emitting Diode (LED) used as a photoreceptor, combined to light source spectrum is correlated to electrical characteristics in order to propose an alternative method to estimate LED junction temperature, regardless of the absolute illumination intensity and based on the direct correlation between the integral of the product of two optical spectra and the photo-generated currents. A laboratory test bench for experimental optical measurements has been set in order to enable any characterizing of photoelectric devices in terms of spectral behaviour, in a wavelength range placed between 400–1000 nm, and of current-voltage characteristics as function of temperature by using two different illumination sources. The temperature is analysed in a range from 5°C up to 85°C, so as to evaluate thermal variation effects on the sensor performance. The photo-generated current of two LEDs with different peak wavelengths has been studied. Research has observed and mathematically analysed what follows: since the photo-generated current strictly depends on the combination between the spectral response of the photoreceptor and the lighting source response, it becomes possible to estimate indirectly the junction temperature of the LEDs by considering the ratio between the photogenerated currents obtained by using two different illumination sources. Such results may for one thing increase knowledge in the fields where LEDs are used as photo-detectors for many applications and for another, they could be extended to generic photodetectors, thus providing useful information in photovoltaic field, for instance.
4
Content available Influence of junction temperature on the spectral power distribution of Light Emitting Diodes
Budzyński Ł
Challenges of Modern Technology
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2015
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Vol. 6, no. 4
3--7
EN
This article describes electrical method for measuring junction temperature of high power LEDs. Measurement system consisting of a temperature controller and a thermostatic chamber was designed and constructed. A number of studies of LEDs in a typical thermal conditions that exist in luminaries were performed. Basing on these results, influence of junction temperature on luminous flux and spectral power distribution of LED was determined. Obtained results allow to optimize the construction of LED lighting fixtures, in the ambient temperature range from 0°C to 100°C, especially in the aspect of improving the photometric properties of the luminaire.
5
Content available Oddziaływanie termiczne pomiędzy źródłami hp LED zainstalowanymi na wspólnym radiatorze
Różowicz A., Baran K.
Prace Instytutu Elektrotechniki
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2014
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Z. 266
87--97
PL
W artykule zaprezentowano model matematyczny pozwalający wyznaczyć temperaturę radiatora, na którym może być zainstalowana dowolna ilość sprzężonych ze sobą termicznie źródeł ciepła. Na podstawie modelu symulacyjnie wyznaczono temperaturę płyty aluminiowej, na której zainstalowano źródła światła LED, będące źródłami ciepła. Symulację przeprowadzono dla kilku przypadków, w których zmieniana była ilość, moc oraz odległość pomiędzy źródłami LED. Oszacowany w ten sposób rozkład temperatury radiatora może być wykorzystany do obliczenia temperatury złącza, która wpływa na podstawowe parametry źródeł LED.
EN
The article presents the mathematical model allowing to determine the temperature of the radiator, on which there can be installed any number of heat sources coupled with each other. Based on the model, the temperature of the aluminium plate with installed LED light sources (being the sources of heat) was determined by simulation. The simulation was performed for several cases, in which the amount, power and the distance between LED sources was different. Thus estimated distribution of the radiator can be used to calculate the temperature of the junction, chich influences the basic parameters of LED sources.
6
Content available remote Improved Electrical Measurement Method for Junction Temperature of Light Emitting Diodes
Shen H., Han K., Liu M., Fan S.
Przegląd Elektrotechniczny
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2012
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R. 88, nr 3b
180-184
EN
The electrical test method (ETM) is used to measure the junction temperature Tj of high brightness LEDs. NI 5922 digitizer and Keithley S2400 source meter were used to build the measurement system. Various measurement currents were used under 1MHz sampling rate. Results of different measurement currents are found to be the same under the same sampling rate and measurement error can be found under low sampling rates. When sampling rate is down to 0.2kHz, measurement error is up to 13.7%.
PL
Zaproponowano metodę pomiaru temperatury złącza diody LED. Określono błąd metody dla różnych częstotliwości próbkowania.
7
Content available remote Measurements of the temperature-dependent changes of the photometrical and electrical parameters of LEDs
Wandachowicz K., Domke K.
Przegląd Elektrotechniczny
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2008
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R. 84, nr 8
114-117
EN
In addition to emitting light, high power light emitting diodes also generate a significant quantity of heat. Heat released in the p-n junction of the semiconductor material markedly increases its temperature and thus indirectly affects the photometric and electric characteristics of LEDs. This paper presents a test stand designed for measuring such characteristics for a wide range of changes of junction temperatures. Junction temperature adjustment can proceed independently of the thermal power released in the LED.
PL
Wytwarzaniu światła w diodach towarzyszy wydzielanie dużej ilości ciepła. Wydzielające się w złączu p-n materiału półprzewodnikowego ciepło zwiększa znacząco jego temperaturę i wpływa pośrednio na zmianę charakterystyk fotometrycznych i elektrycznych diody. W pracy przedstawiono stanowisko badawcze pozwalające mierzyć te charakterystyki dla szerokiego zakresu zmian temperatury złącza. Regulacja temperatury złącza może przy tym przebiegać niezależnie od wydzielanej w diodzie mocy cieplnej.
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