A Transformerless Hybrid Modular Step-up DC/DC Converter for Bipolar and Symmetrical Monopolar HVDC Interconnection

Serving as DC transformer in HVDC grid, high-voltage and high-power DC/DC converter is one of the most important HVDC devices. This paper proposes a novel hybrid modular transformerless step-up DC/DC converter for symmetrical monopolar and bipolar HVDC grids interconnection, which can still operate even though a DC pole-to-ground short-circuit fault takes place. This DC/DC converter features high efficiency, low capital costs and small footprint. Operation principle is introduced and simulation results from MATLAB/Simulink verify the feasibility of the proposed DC/DC topology.