Design study and scaled experiments for high-power DC-DC conversion for HVDC-systems

The design of a high-efficiency DC-DC power converter, which can be used in high-voltage DC power transmission and distribution applications, is given in this paper. The DC-DC power converter, named an electronic DC-transformer, consists of a zero-voltage switching, phase-shift controlled, full-bridge IGBT-inverter, a high-frequency transformer and a voltage rectifier. The converter is analyzed and a design of a 1 MW electronic DC-transformer is presented. Also simulation and test results of a 3.6 kW, scaled model of the DC-transformer are presented. Further a description of methods to control voltage and current, by introducing a varying time delay between the two legs of the inverter, is presented in this paper.