Further improving heat dissipation from large aluminum electrolytic capacitors

In prior studies we have reported considerable progress in improving the heat dissipation due to ripple current for large aluminum electrolytic capacitors [elcaps]. Due to these enhanced thermal construction techniques, elcaps are now commercially available with very high ripple current ratings at moderate cost. In those same studies, some effort was devoted to the improvement of the heat dissipation from the elcap into the external environment. This paper extends that work. A number of attempts have been made to enhance the removal of heat from the exterior of large elcaps with varying degrees of acceptance. We describe several approaches to external heat removal including an active heat removal system, which can deliver total thermal resistances around 1 C/Watt with a minimum of additional required space. It is believed that these approaches will be useful to those equipment designers who place a high priority on achieving the greatest possible circuit densities without resorting to liquid cooling.