A high efficiency high power step-up resonant switched-capacitor converter for offshore wind energy systems

Offshore wind farm with an internal medium voltage DC (MVDC)-grid collection connected to high voltage direction current (HVDC) transmission is a promising option for the development of high power long distance offshore wind farms. Medium voltage high power DC/DC converters with high step-up conversion ration are the key components in these electrical systems. This paper presents a high efficiency step-up resonant switched-capacitor (SC) converter for offshore wind energy systems, which is characterized by soft switching condition for all switches and diodes. This significantly reduces switching losses and higher switching frequency is feasible to reduce the overall system volume. Comparison with other step-up SC converters shows that the new SC converter needs much less filter capacitors. The experimental results of a 24 kW prototype are presented to verify the proposed converter.