Two-Phase Cooling of Hot-Swappable Modular Converters

Modular converters are attractive, because they provide features such as scalability, redundancy and hot-swapping of modules. The cooling of modular converters presents some challenges, that are addressed in this paper. Two-phase cooling can be used to extend the performance of air cooling, while retaining its advantages in terms of electrical insulation and easy plugability. As demonstrated by numerical simulations, an L-shaped thermosyphon can be optimally integrated in a power module. This allows combining high power density, reasonable pressure drop and thermal homogeneity. The effect on capacitor lifetimes is also investigated. On the converter level, the cooling during hot-swapping is analyzed. It is shown that removal of a module leads to a drop in cooling performance which can be compensated by switching on an otherwise redundant fan.