Improved thermal management of multi-level converter building module to realize higher power density

Multi-level converters can essentially reduce the harmonics and Electro Magnetic Interference (EMI). The number of output levels should be higher drastically to realize extremely high quality output and low EMI. However, as the number of levels increases, the number of circuit components also increases and implementation will be difficult significantly. Thus, flexible building platform of the multi-level converters suitable for the higher number of the output levels should be developed. As a solution to this problem, a concept of Multi-Level converter Building Modules (MLBM) to realize the multi-level converter with a higher number of output levels systematically has been proposed in ECCE 2013. A prototype of the MLBM has been constructed as a 5-level flying capacitor converter with extendable configuration. However, in the previous version of the MLBMs (MLBM Type-I) without any heat sinks, there is a restriction to increase the rated power of the converter when plural MLBMs are combined. In this paper, the improved thermal management of the MLBM is investigated to realize higher power capacity as well as higher number of levels. The module configuration to improve the heat dissipation of devices by using aluminum-based printed circuit board (MLBM Type-II) is developed. The proposed configuration enables to obtain the higher power density in the multi-level converter with higher number of output levels.