This paper presents an overview of the DC-DC power converters dedicated to HVDC proposing a classification based on their structure.
Comparison between numerical and analytical methods of AC resistance evaluation of medium frequency transformers : validation on a prototype
In the future, medium-frequency transformers (with a frequency range of 5-100 kHz) will be major components in dc-dc converter applications, for both medium-voltage direct current and high-voltage direct current networks.
Analysis of voltage and current unbalance in a multi-converter topology for a DC-based offshore wind farm
High Voltage Direct Current (HVDC) is increasingly being used for electric power transmission over long distances.
Gate-drive power supplies in medium voltage and high voltage direct current (MVDC / HVDC) applications require medium to high voltage insulation.
With the development of wide bandgap semiconductors, voltage ratings of 10kV and more become realistic. As a consequence, it is now mandatory to propose a suitable packaging. Ceramic-metal substrates are an established technology for voltages up to 3.3kV, but they exhibit some weaknesses for higher voltages.
The failure mode of press-pack-type packages dedicated to SiC devices is experimentally analyzed in order to investigate their use for HVDC applications. Single SiC Schottky diode samples have been submitted to short-circuit conditions and continuous current flow test.
The article describes a feedback Preisach hysteresis model equivalent circuit implementation of a medium frequency single-phase transformer being a part of a high power and high efficiency DC-DC converter.
High Voltage Direct Current (HVDC) converters are composed of hundreds of semiconductor switches connected in series to sustain the rated voltage of the converter (several hundred of kilovolts). Because of the large number of switches, it is highly probable that at least one of them will fail during the lifetime of the converter. Such failure should not cause the entire converter to shut down, despite the series connexion of the switches. As a consequence, each switch should be designed so that upon failure, it becomes a short circuit and keeps carrying the current (“fail-to-short” behaviour).
PhD Albert PEREIRA “Design methodology of a medium frequency transformer for high voltage and high power DC-DC converters”
The transmission and distribution of electric power is normally made by ac networks (50 Hz or 60 Hz), where one of the key elements of this infrastructure is the power transformer; used for more than a century, its design is very well understood, with a level of operating efficiency normally greater than 99%.