Unidirectional thyristor-based DC-DC converter for HVDC connection of offshore wind farms

This paper introduces a unidirectional MVDC-HVDC converter for ‘all DC’ connected offshore wind farms. This converter combines the low power losses of thyristor based converters and the control abilities of voltage source converters, together with low power electronics component count. A high step-up ratio is achieved by an input parallel output series configuration. The use of medium frequency is discussed and inductance design conditions are given. A control scheme is proposed and validated by simulations. The converter high efficiency is also observed. The presented analysis shows a potential feasibility and benefits of this novel unidirectional thyristor-based DC-DC converter.