Johannes Kolb, Felix Kammerer, Philip Grabherr, Mario Gommeringer, Michael Braun

PCIM Europe 2013, Nuremberg, Germany

The Modular Multilevel Converter (MMC) is an upcoming topology for high efficiency power
conversion not only in the high voltage range but also for low voltage applications. This contribution
presents several improvements in the hardware design, control and modulation of a low
voltage MMC to increase the efficiency over 99%. Simply standard Silicon-MOSFETs and no
SiC- or GaN-transistors are used as semiconductor switches in the prototype converter. The
detailed analysis of the efficiency also shows an excellent performance in the low power range,
which yields to a very flat efficiency curve. Therefore, the MMC is especially suited for grid
connected inverters, e. g. in applications like DC microgrids, photovoltaics etc.