A Multi-port Power Flow Controller for HVDC Networks

This thesis proposes a multi-port converter structure for high-voltage dc (HVDC) applications to facilitate power flow routing between multiple dc networks. Power flow control is achieved via the injection of incremental dc voltages between the networks, thus the converter structure is only rated for a fraction of the rated power and voltage of the connecting dc networks. There are four variants of the structure, each offering unique advantages for deployment. These variants, and the modules that comprise them, are presented. Simulation studies demonstrate three-port bidirectional power flow control between networks of similar voltage. The proposed converter structure is shown to route power between the networks using modules with power ratings on the order of 2-3% of the transmitted power. Thus, the proposed converter structure offers a highly cost-effective means of routing and controlling dc power flows within emerging HVDC grids.