High power IGCT-MMC submodule design based on diodes in parallel

This paper presents an IGCT-MMC submodule design based on diodes in parallel connection applied in modular multilevel converter valve. In contrast to traditional MMC submodule design based on single diode, the proposed arrangement with diodes in parallel connection reduces the anode inductance and clamping capacitance which leads to a compact design of IGCT submodule. By analyzing diode electrical characteristics and thermal impact to current sharing performance, proposes the design principle of diodes in parallel connection. IGCT-MMC submodule prototype is developed based on diode in parallel, the pulse test of power device and power cycling test are performed on the IGCT submodules. Safety switching capability of power devices, and long-term operation capability of IGCT submodule are verified as well.