Improved Thermal Simulation of Aluminum Electrolytic Capacitor for Lifetime Prediction

Abstract

The aluminum electrolytic capacitors (Al-Caps) has been regarded as one of the weakest components of power electronic converters in various customer applications. The core temperature of Al-Cap decides its operating lifetime on a considerable scale. To accurate analyze Al-Cap’s core temperature, this paper proposed an improved thermal simulation method of Al-Caps, which consists of twofold modeling, i.e. component level and board level. For the component level, the finite element (FE) simulation is established in ANSYS Icepak according to its package structure and geometry. For the board level, a zoom-in modeling method is carried out, which is able to analyze Al-Cap’s core temperature in a converter with less computation cost comparison. The proposed thermal simulation method is illustrated by the electrolytic capacitor in a LED driver. Based on the improved thermal simulation analysis, the lifetime prediction results of Al-Caps with different package sizes are compared to select a more reliable design.