Study of static converters related ripple currents effects on supercapacitors ageing within DC networks

Although supercapacitors are more cyclable than batteries, as they don´t imply faradic reaction for energy storage, they are subject to ageing. The main ageing causes are temperature and voltage. This article investigates the effect of a supplementary ageing cause which is high frequency ripple current. Indeed, ripple current is a problem happening for DC networks using power electronics converters (as in hybrid vehicles, domestic network ...). Some previous results for 1 kHz ripple current tended to show a slight effect of HF current on supercapacitors ageing speed [1]. In this article two other frequencies will be studied. The first one (100 Hz) is near from the frequency employed for domestic networks (due to rectifiers) and the second one (10 kHz) is close from the frequency of onboard power networks (due to DC-DC converters). Experimental results show that studied ripple currents are transparent in term of ageing. These results are interesting for industrial use as they prove that supercapacitors can be inserted indifferently in stationary and onboard networks without taking into account ripple currents.