This M.Sc. thesis deals with the problem of evaluating the thermal image and power losses of power converters. In this respect, it is divided into two parts.
The first part of the thesis is focused on heat transfer in IMS printed circuit boards (PCBs). A simulation model of the power converter PCB (a transistor leg) is designed and an analysis of the effects of using different modeling details on the accuracy of the estimated thermal image of the converter is presented. A comparison of the simulation runs of several test IMS circuits with dielectrics with different thermal conductivity factors is performed and presented. The results of the analysis of the final temperature of the circuit at constant power dissipation as a function of the thermal conductivity factor are provided. The suitability of the proposed approach and obtained simulation results are evaluated and confirmed through extensive measurements.
The second part of the thesis focuses on the evaluation of the power dissipation of power converters using an indirect method. This involves the use of a specially designed temperature-controlled chamber in which the power losses of the analyzed power converter are estimated based on the indirect measurement of the generated heat dissipated from the system using Peltier elements. The aim of the study was to verify the suitability of the proposed concept and to assess whether it is reasonable and possible to develop an algorithm that would enable estimation of the power loss of the converter with a relatively simple measurement setup and without interfering with the electrical part of the circuit.
The results of the two studies show good agreement between measurements and simulations. The reproducibility between samples and between measurements is high. The results of the second study also show the feasibility and viability of indirect measurement of power losses, while further work is required to investigate the effects of convection for additional accuracy.
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