A concept of high power DC/DC converter with double low power outputs

This paper proposes a circuit topology to draw additional dc power outputs from a dc transmission line by series-connected circuits. It is based on a conventional concept of HVDC tap but the HVDC tap is duplicated in this paper in order to reduce current fluctuations on the dc transmission line. Inversed switching pattern between the two HVDC tap results in small current fluctuation and realizes additional low dc power outputs. This circuit topology is expected to be applied to a dc transmission system for offshore wind power, etc. In this paper, the operating characteristics are discussed in detail based on simulation study. The condition to achieve the soft-switching is also revealed. In addition to this, operating characteristics of the total system are verified by numerical analysis to investigate the availability of the proposed circuit.