A Multiport Cascade Boost-buck Converter for IDCPFC Application in Multi-terminal HVDC System

By growing renewable energy resources, the application of multi-terminal DC (MTDC) grids has been increased. Power flow management is one of the most important challenges which DC grids face in developing. DC power flow controllers (DCPFC) provide an appropriate solution to encounter with this challenge. This paper proposes a multiport cascade boost-buck converter (MCBBC) as an interline dc power flow controller with reduced number of switches and then evaluates the control performance of balancing and regulating the DC branch currents. A master-slave control strategy has been applied to the proposed MCBBC to appropriate performance. The control strategy has features that enable the proposed converter circuit to be developed as an N-port IDCPFC. In addition, the voltage regulation control approach is utilized to ensure the bus voltage regulation and it provides DC power flow control within the MTDC grid. To evaluate the performance of the MCBBC and the proposed control strategies, a 3-terminal DC grid have been considered. The simulation results, obtained through the MATLAB/Simulink software.