Power Loss Analysis and Performance Study of MMC‐based HVDC System Using 10 kV SiC Device

ABSTRACT

The emergence of 10 kV silicon carbide (SiC) devices presents a viable approach to drastically reduce the SM count, facilitating more compact and efficient MMC designs. Nevertheless, the power loss and overall system performance are unknown when using 10 kV SiC devices. This paper systematically investigates the power loss and overall performance of MMCs with 10 kV SiC devices compared with traditional 3.3 kV silicon (Si) submodules (SMs). First, it studies the switching performance of 10 kV SiC devices by testing to obtain device‐specific loss parameters. Then, the accurate power loss analysis method of the SM and MMC systems is presented. A comparative study is made between the 10 kV SiC device and the 3.3 kV Si device for the MMC‐based high voltage direct current (HVDC) system, including losses, efficiency, harmonics, and capacitor voltage fluctuations. Results indicate that 10 kV SiC devices significantly reduce the switching power loss by over 60%. The conduction loss is reduced by 65.6% at light load while this loss is similar with Si device at the heavy load. The overall performance of the MMC system is also improved in terms of circulating current and capacitor voltage ripple.