A methodology for studying aluminum electrolytic capacitors wear-out in automotive cases

Electrolytic aluminum capacitors used in electric drive for automotive are deemed to be the weakest components of static power converters. A lot of studies have been made to estimate their aging but only for a nominal point. This paper presents a specific operation cycle implementation to study the impact of a variable and more realistic thermal cycling. Moreover, an improvement of the classical electrical model for an electrolytic capacitor is proposed by adding a diffusion-relative element called “anomalous diffusion”. Experimental results show the interest of this element for an impedance-fitting. Finally, thermal measurements validate thermal cycling simulations.