Electrolytic capacitors are an importantudcomponent within power electronics systems which are known toudexhibit poorer reliability compared to other components withinudthe system. In this paper, the changes in electrical parametersud(capacitance and equivalent series resistance) which occur asudelectrolytic capacitors age are characterised at regular intervalsudover the life of the capacitors. Ageing is observed under threeuddifferent bias conditions: no bias; constant voltage bias andudsquare wave excitation and at two different ambientudtemperatures. The data captured within this work presents theudchanges in capacitor properties from new, reaching to a pointudwhich the capacitor parameters have changed sufficiently, suchudthat the capacitor can be considered to have failed. Such data willudprove valuable in the development of a system designed touddetermine the state of health of a capacitor, or could be used toudpredict its remaining useful lifetime.
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