Dynamic modeling and internal characteristic simulation research of MMC-UPFC

The unified power flow controller (UPFC) based on modular multilevel converter (MMC) has good harmonic characteristics, such as being easy to modular design, small footprint, no series connected power semiconductor devices. It has been widely studied in transmission to improve line transmission capacity and system transient stability, and to optimize power flow to reduce network losses. The dynamic modeling of UPFC based on MMC is the basic of revealing the working mechanism and designing the controller. Switching cycle average model and simple switching cycle average model were gradually established, and the simulation about internal characteristic of UPFC based on MMC was conducted on RTDS platform. Simulation and analysis results show that internal dynamics of the proposed controller has great difference in its series and parallel side, the conclusion and the established dynamic model are mutual corroboration. ©2014 Chin. Soc. for Elec. Eng.