Hardware design and key submodule testing of the world's first single-level press-pack igbt based modular multilevel converter for VSC HVDC

For the Modular Multilevel Converter (MMC) based VSC HVDC, typical topology of its submodules is a half bridge circuit and plastic module IGBTs (PMIs) are common power devices for a submodule. However, PMIs have a relatively short lifetime and open-circuit failure mode, which make them less suitable for power systems. On the other hand, press-pack IGBT/IEGT (PPIs) can offer a much longer lifetime, the unique short-circuit failure mode (SCFM), and higher current carrying capabilities. Hence, PPIs are perfect device for MMC HVDC, especially for future higher rating systems. The ±160kV/200MW MMC converter is the largest one in the Nan'ao multi-terminal VSC HVDC system, and it is also the world's first MMC that is based on single-level PPI devices. This paper will look into detailed hardware design of this MMC converter from device to valve, it will also provide key testing results of submodules.