Thermal resistance of snap-in type aluminum electrolytic capacitor attached to heat sink

Aluminum electrolytic capacitors are standard components in power electronic equipment. Their performance and lifetime strongly depends on their operation temperature. Hence, controlling their temperature is essential for reliable operation of the equipment. For standard snap-in type capacitors, which are common in low power converters (~20 kW), direct air cooling is the standard solution. This paper presents ways to improve the cooling performance by attaching the capacitor to a heat sink. Two different configurations are investigated: Heat removal through the base of the capacitor and heat removal through its sidewalls. When applied with an aluminum heat sink in natural convection, both methods provide significantly reduced thermal resistances, approximately 66% lower compared to direct air cooling by natural convection.