Włodzimierz Janke

A System for Cooling Electronic Elements with an EHD Coolant Flow

A system for cooling electronic components where the liquid coolant flow is forced with ion-drag type EHD micropumps was tested. For tests we used isopropyl alcohol as the coolant and CSD02060 diodes in TO-220 packages as cooled electronic elements. We have studied thermal characteristics of diodes cooled with EHD flow in the function of a coolant flow rate. The transient thermal impedance of the CSD02060 diode cooled with 1.5 ml/min EHD flow was 7.8°C/W. Similar transient thermal impedance can be achieved by applying to the diode a large RAD-A6405A/150 heat sink. We found out that EHD pumps can be successfully applied for cooling electronic elements.

Thermal conductivity of silicon doped by phosphorus: ab initio study

Abstract An original approach to the theoretical calculations of the heat conductivity of crystals based on the first principles molecular dynamics has been proposed. The proposed approach exploits the kinetic theory of phonon heat conductivity and permits calculating several material properties at certain temperature: specific heat, elastic constant, acoustic velocity, mean phonon scattering time and coefficient of thermal conductivity. The method has been applied to silicon and phosphorus doped silicon crystals and the obtained results have been found to be in satisfactory agreement with corresponding experimental data. The proposed computation technique may be applied to the calculations of heat conductivity of pure and doped semiconductors and isolators.

Symulacje PSPICE przetwornicy BUCK oparte o modele uśrednione

The article presents examples of applications of averaged models in PSPICE simulations of power converters. The results of simulation of transients in the BUCK converter and its frequency characteristics are shown. A comparison of the results obtained for the complete model (a pair of switches and PWM generator) and largeand small-signal averaged models has been performed. (PSPICE simulations of BUCK converter, based on average models). Słowa kluczowe: przekształtniki mocy, przetwornica typu BUCK, modele uśrednione, PSPICE, symulacje stanów przejściowych, charakterystyki częstotliwościowe.

Influence of operation conditions on true-static DC characteristics and on electro-thermal transient states in silicon carbide Merged PiN Schottky diodes.

In this paper, measured and calculated non-isothermal DC characteristics of silicon carbide MPS devices are investigated, with special attention paid on critical parameters, such as maximum current and junction temperature at which a thermal runaway may occur. Electro-thermal transient states in single MPS devices (forward surge current tests) and in the simple Greatz rectifier are simulated and compared to measurements. Various electro-thermal models of SiC SBDs, with a simplified, effective procedure for calculations of junction temperature are proposed.