High-boost, resonant-type DC-DC converters at power interfaces for interconnecting DC generation to AC main grids

This paper presents the design, simulation and experimental performance of a scaled-down advanced DC-DC converter prototype. The configuration uses soft-switching and combines a resonant circuit with a boost converter resulting in a voltage-gain of 10 and. Through a cascade arrangement of converters, the voltage gain is increased to 50. The DC-DC converter is primarily designed as converter station operating as part of a modified HVDC link which interconnects DC power into the AC system. Once the converter is mathematically described, a number of cases of study for open-loop and closed-loop conditions are presented. In order to confirm the DC power transfer, the modified HVDC link -using a 21-level MMC power station at the AC-side- is simulated. The experimental results are presented at final section. The DSP-based control is implemented in the TMS320F28335.