Author
P. Kawka
Other affiliations: Ghent University
Bio: P. Kawka is an academic researcher from Agilent Technologies. The author has contributed to research in topics: Nyquist plot & Thermal resistance. The author has an hindex of 2, co-authored 3 publications receiving 49 citations. Previous affiliations of P. Kawka include Ghent University.
Papers
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TL;DR: In this paper, it was shown that if the thermal impedance Zth(jw) of an electronic package is represented in a Nyquist plot, the curve obtained can be fitted very well to a combination of a few (n) circles, n varying between 2 and a maximum of 5.
Abstract: It will be shown in this contribution that if the thermal impedance Zth(jw)of an electronic package is represented in a Nyquist plot, the curve obtained can be fitted very well to a combination of a few (n) circles, n varying between 2 and a maximum of 5. For each of these circles, it is sufficient to know the radius and the coordinates of the center point or just three parameters. With 3n parameters the entire behavior of the impedance can be represented and consequently, the dynamic behavior as well.
37 citations
01 Sep 2006
TL;DR: In this article, the authors present dynamic thermal analyses of a POF amplifier based on the transient junction temperature measurements performed during the circuit cooling process and demonstrate the influence of the contact resistance and the positio n of the entire cooling assembly on the obtained results.
Abstract: This paper presents dynamic thermal analyses of a p ower amplifier. All the investigations are based on the transient junction temperature measurements performed during the circuit cooling process. The presented results incl ude the cooling curves, the structure functions, the therma l time constant distribution and the Nyquist plot of the t hermal impedance. The experiments carried out demonstrated the influence of the contact resistance and the positio n of the entire cooling assembly on the obtained results.
13 citations
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TL;DR: In this article, the authors present dynamic thermal analysis of a power amplifier based on transient junction temperature measurements performed during the circuit cooling process, including the cooling curves, the structure functions, the thermal time constant distribution and the Nyquist plot of the thermal impedance.
Abstract: This paper presents dynamic thermal analyses of a power amplifier. All the investigations are based on the transient junction temperature measurements performed during the circuit cooling process. The presented results include the cooling curves, the structure functions, the thermal time constant distribution and the Nyquist plot of the thermal impedance. The experiments carried out demonstrated the influence of the contact resistance and the position of the entire cooling assembly on the obtained results.
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TL;DR: In this article, the thermal impedance of a silicon substrate with a uniform heat source on top was calculated numerically using the boundary element method, using two circular arcs for the lower frequency arc and for the high frequency arc.
44 citations
16 Mar 2014
TL;DR: In this article, an Effective Heat Propagation Path (EHPP)-based online adaptive thermal model for IGBT modules is proposed to quantify the impact of substrate solder cracks on the heat propagation inside the IGBT module.
Abstract: The information of junction temperature is crucial for operation management of IGBT modules In practice, junction temperature is typically estimated by using an electrothermal model IGBT modules are subject to various aging processes during operation, some of which, eg substrate solder crack, changes the thermal impedance of an IGBT module However, in the literature little work has included the aging effects into online thermal behavior modeling of IGBT modules This paper proposes an Effective Heat Propagation Path (EHPP)-based online adaptive thermal model for IGBT modules, where the EHPP is proposed to quantify the impact of substrate solder cracks on the heat propagation inside the IGBT modules A straightforward relationship between substrate solder crack and the degree of nonuniformity of case temperature distribution is established Based on the EHPP, the parameters of a thermal network, eg, a Cauer thermal network, are adjusted online to track the thermal behavior changes of the IGBT modules caused by substrate solder cracks, leading to an adaptive thermal model The proposed adaptive thermal model is validated by comparing with finite element analysis (FEA) simulation results for a commercial IGBT module
42 citations
TL;DR: In this article, the authors presented an asymmetric multi-peak fitting method, bi-Gauss, to separate the overlapping peak based on the results of the biGauss method, the kinetic mechanism was obtained using the integral master plot method, followed by the determination of the activation energy by the integral iso-conversional non-linear (NL-INT) method.
Abstract: In this paper, the derivative thermogravimetry (DTG) curve displays an overlapping peak which consists of two subpeaks for the major oil-producing stage of Indonesian oil sand This study was conducted to supplement the insufficiencies of the previous studies, which neglected or oversimplified the processing of the overlapping peak and did not determine the kinetic mechanism First of all, we assume a two-component parallel reaction model to describe the mass-loss process of the major oil-producing stage (overall stage) to obtain the separated stages Then, we present an asymmetric multi-peak fitting method, bi-Gauss, to separate the overlapping peak Based on the results of the bi-Gauss method, the kinetic mechanism was obtained using the integral master plot method, followed by the determination of the activation energy by the integral iso-conversional non-linear (NL-INT) method The results show that the bi-Gauss method can produce satisfactory fitting results Moreover, the separated stages follow single mechanism; while the overall stage does not follow a single mechanism and the mechanisms of the front and back segments of the overall stage are in accordance with those of the separated stages, which prove the reliability of the two-component parallel reaction model
37 citations
TL;DR: In this paper, the thermal behavior of a laboratory model for an underground cable has been investigated experimentally and the results are represented by thermal impedances, which are then used to obtain the thermal time constant distribution and the structure functions.
35 citations
TL;DR: In this paper, a downscaled laboratory model for an underground cable has been investigated experimentally with respect to these parameters, and a dynamic thermal analysis has been conducted to provide the complex thermal impedance, thermal time constant distribution and cumulative structure function.
30 citations