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Badanie wpływu wybranych czynników na parametry cieplne tranzystorów mocy MOS

Górecki K., Zarębski J.

Przegląd Elektrotechniczny

2009

R. 85, nr 4

159-164

W pracy przedstawiono problem wyznaczania wartości parametrów cieplnych tranzystorów MOS mocy oraz zaprezentowano i przedyskutowano wyniki pomiarów ilustrujących wpływ takich czynników, jak rodzaj obudowy, wielkość radiatora, ułożenie przestrzenne badanego tranzystora oraz wydzielanej w nim mocy na rezystancję oraz przejściową impedancję termiczną. Przedstawiono również wyniki pomiarów rozkładu temperatury na powierzchni nieobudowanej struktury tranzystora MOS mocy przy różnych warunkach chłodzenia tego elementu.

In the paper the problem of measurements of the thermal parameters values of MOS power transistors is considered. The results of measurements showing the influence of such factors as the type of the case, the dimensions of the heat-sink, the orientation of the investigated transistor and the dissipated power on the thermal resistance and the transient thermal impedance of the device are presented and discussed. The measurements results of the temperature distribution on the surface of the uncapsulated MOS power transistor chip for different cooling conditions of this device are presented, too.

Korelacja parametrów lodowych z parametrami termicznymi zimy i jej przestrzenne zróżnicowanie w rejonie ujścia Odry

Girjatowicz J.P., Olechwir T.

Zeszyty Naukowe. Marine Sciences / Uniwersytet Szczeciński

1998

Nr 4

37-52

The aim of the study is the examination of relations between ice and winter thermal parameters and the division of waters of the mouth of the Odra river into regions basing on differential values of computed correlation coefficients. Relations between ice (S, L, H) and thermal (T, Z) parameters were examinated with the correlation and regression analysis. There were examinated many regression functions as linear, logarythmic, polynomial, exponential and multiplicative. There were computed correlation coefficients (r). There was also performed the estimation od statistical significance of these relations using Fisher-Snedecor's significance test (F). Statistical significance of ice relations with winter thermal conditions is depended not only on the kind of chose ice thermal parameters but also on the kind of function and differential physiographical conditions of the water area. It was proved that amond different examined functions the function of polynomial of order 2 (W) approximates in the best way the empirical points in the system of rectangular coordinates. In some cases natural logarithm (Ln) and linear (P) functions approximate them well enough as well. All these relations (204) are high statistical significant ones, even on significance level a = 0,01. The ice parameter which correlates with thermal parameter the best is maximum ice thickness (H). The lenght of season (S) correlates the worst. The influence of thermal parameters on significance of ice relations is sufficiently differential and is depended on the kind of chosen function, ice parameters and of the water area. In the water area in the mouth of the Odra the higest correlation coefficients are calculated for Szczecin Bay. It is shallow sheltered water area, which is characterized by the weakest water motion. For deeper areas with stronger water motion (sea, straits, rivers, fairway, canal) the coefficients are lower, that indirectly show the marked influence of not thermal factors (water motion, wind, anthropogenic activity). There were divided three types of regions which are characterized by distinct differentiation of correlation coefficients: 1) rivers and straits which are characterized by the lowest values of correlation coefficients; 2) the Pomeranian Gulf , characterized by the higher than for rivers and straits values of correlation coefficients; 3) the Szczecin Bay and adjacent lakes which are characterized by the highest values of correlation coefficients. The distinct differentiation of correlation coefficients of ice relations indirectly tells about the differential hydrological regime, with ice system included, of those regions.