Research of MMC-UPFC Control Strategy

Abstract

The unified power flow controller (UPFC) as the intelligent power grid energy controller is a more comprehensive flexible ac device that can improve power grid operation, transmission levels and power quality. The differences in UPFC topology and its control strategies have an important impact on its output characteristics. Firstly, the UPFC topology and its control strategy are summarized in the paper, and then the power flow regulation mechanism is also analyzed. The mathematical models of series and parallel side converters are established in the three phase stationary coordinate, the UPFC model and its control characteristics are analyzed in the two- phase rotating(d q) and stationary (α β) coordinate system, and design the control strategies under the a P coordinate system to realize decoupling control. Finally, the UPFC simulation model based on MMC is built in the PSCAD/EMTDC simulation environment to simulate and analyze the adjustment characteristics of active and reactive power flow.