Series interline DC/DC current flow controller for meshed HVDC grids

Abstract

This paper proposes a DC/DC Current Flow Controller (CFC) for meshed High Voltage Direct Current (HVDC) grids. The CFC has the advantage of a simplified structure that allows to use minimum number of switches when unidirectional current flows through the DC lines are expected. An extended CFC topology able to operate with all the possible current flows is also presented. Then, the operating principle of the CFC is discussed and its structure is compared with a dual H-bridge analysing advantages and disadvantages. The work also details the applied modulation strategy and the control methodology. Finally, a 5-terminal meshed HVDC grid is used to validate the CFC by means of simulations.