Accelerated Aging Method and Lifetime Evaluation of Aluminum Electrolytic Capacitors for Power Electronic Application

Abstract

Due to their low cost and high power density, Aluminum Electrolytic Capacitors (AECs) are widely used at the dc-link of the inverter for power decoupling. Due to poor reliability of AECs, accelerated life tests (ALTs) are used to evaluate their operational life. Various ALTs are proposed in literature by applying electrical and thermal stresses. Application of reverse voltage is not explored in sufficient details as an ALT in literature. This is mainly due to run-away behavior of AECs under reverse bias. This paper discusses an ALT using application of reverse voltage in a current controlled setup. Further it proposes a method to correlate the operational life of AEC used in an application with the accelerated aging of the AEC using Physics of Failure based model. The experimental results show that the proposed ALT method, is almost two times faster than the conventional methods. This helps in early evaluation of the operational life of AECs. Also, an analysis of the effect of instrumental error on the lifetime estimation is carried out. This analysis shows that using the proposed method, the estimation is more accurate than conventional methods.