An Expandable Interline DC Power-Flow Controller

The DC power flow controller can effectively solve the problem of insufficient freedom of power flow control in the DC grids, which is important for maintaining the safe and stable operation of the AC/DC hybrid system. Firstly, the working principle of the existing power flow controllers are briefly analyzed, and their shortcomings in practical applications are pointed out. Aiming at the shortcomings of existing power flow controllers, a novel circuit topology of interline DC power flow controller (IDCPFC) is proposed in this paper, which is easy to be extended for modularization design. Secondly, operating principles and control strategies are analyzed. Finally, two meshed dc grids are simulated in PSCAD to validate IDCPFC with cases of steady state and power change state. Simulation results show that IDCPFC can realize accurate power flow control.