Predikce životnosti, testování a měření parametrů foliových kondenzátorů

Abstract

Cílem disertační práce je shrnutí degradačních mechanismů u svitkových kondenzátorů s metalizovanou elektrodou.Na počátku studia degradace svitkových kondenzátorů se vyskytl problém s měřením parametrů u kondenzátorů s kapacitou větší než jednotky mikrofaradů. Byly hledány metody jak zatěžovat kondenzátory a jak je měřit. V rámci hospodářské smlouvy s firmou ZEZ Silko, s. r. o. byl vyvinut pro zatěžování kondenzátorů přístroj využívající sériovou a paralelní rezonanci. Dále bylo vyvinuto testovací zařízení, které měří parametry kondenzátoru s využitím přechodných dějů. Kondenzátor je v tomto případě zatížen impulzně proudy o špičkové hodnotě až 2500 A.

This work aims to summarize the degradation mechanisms of a film capacitors with a metalized electrode.At the start of the study of the degradation of film capacitors, there was an issue with a measurement of capacitors parameters if they had a capacity higher than units of a micro farad. Methods were researched to stress capacitors and measure their parameters. Within the scope of cooperation with our industrial partner ZES Silko, a device was designed for stressing capacitors using series-parallel resonance. Also, test equipment for measurement of capacitor parameters using transient event was constructed. During measurement with this equipment, the tested capacitor is stressed with impulse current which peaks at 2500 A.During measurement, result evaluation has created a model of a capacitor with distributed parameters which describes the degradation of film capacitors — specifically, capacitors with a damaged connection between electrodes and schoopage. This model respects non-homogeneity and uneven aging which is represented as frequency dependence of capacity, the real part of impedance and dissipation.An experiment was conducted which focus on monitoring of degradation mechanisms of film capacitors caused by corrosion of the electrodes. This degradation is due to the penetration of humidity into the capacitor package. Tested capacitors were aged by increased ambient temperature and humidity. Special samples of electrode systems were constructed. In these systems were both conductive layers contacted on both sides to better examine variations of resistivity during the degradation process. This type of connection eliminates the influence of the dielectric and enables to measure the variation of resistivity with better precision.