Middle Frequency Solid State Transformer for HVDC Transmission from Offshore Windfarm

This paper investigates the solid state transformer applied for the HVDC transmission from the offshore windfarm. The 5kVA experimental setup is developed and comparison of up to 1200Hz operation. Dependency of the loss in the transformer with different core materials to frequency is investigated. Frequency loss dependency of nano-crystaline and amorphous core materials are compared in experimental measurement. Nano-crystaline material called "FINEMET" is the best performance, although amorphous seems to have better cost performance. It is also indicated that the converter voltage causes the larger loss in the transformer than the sinusoidal power supply.