Hybrid offshore HVDC converter with diode rectifier and Modular Multilevel Converter

This paper presents a hybrid converter for offshore HVDC applications, consisting of diode rectifiers and a Modular Multilevel Converter. The main task of the Modular Multilevel Converter is to support the wind park with auxiliary power during low wind speed periods, thus avoiding an extra AC cable for auxiliary power. Using the Modular Multilevel Converter also during normal operation of the HVDC link can result in a better DC current with a smaller DC line inductance. The proposed solution is validated with a simulation model based on Simulink Plecs and an experimental setup.