Modular Hybrid Series-Parallel DC-DC Converter for HVDC to MVDC Applications

The benefits of high voltage direct Current (HVDC) technology have made it indispensable for power systems. They consist of lower losses, simpler asynchronous grid connections, better controllability, increased system availability, and a decrease in short-circuit currents. This article introduces a new modular hybrid series-parallel DC-DC Converter (MHSPDC) topology designed for efficient power transfer in HVDC- medium voltage direct current (MVDC) applications. Each phase of a series DC-AC structure and a parallel AC-DC structure, interconnected by a single-phase isolated transformer. This new topology offers significant reductions in footprint and initial investment costs while enhancing converter efficiency. The article provides a brief description of the circuit configuration, operational principles of the converter and mathematical analysis of capacitor sizing used in the converter topology. The MATLAB/PSCAD simulation software is utilized to validate the novel configuration. During the simulation, a phase disposition technique is employed as PWM for converter switching.