A power conversion system for offshore wind parks

This article presents a power conversion system for offshore wind parks based on a high voltage generation, high frequency AC link with bidirectional switches and DC power collection and transmission to shore. All the converters are located in the nacelle of the wind turbines and the turbines are connected in series on the output side of the AC/DC converter and connected to shore without any further transformation stages. The electrical system, from the generator to the grid connection of the turbine, is modeled in PSCAD. The model consists of an induction machine, a 3-phase AC to single phase AC converter, a high frequency high power transformer and a full-bridge converter. The AC-AC converter is based on bidirectional switches with reverse-blocking IGBTs and the switches are controlled with a dedicated switching pattern. The simulations show that the switching pattern gives the expected square wave voltage from the AC-AC converter. The new converter topology is expected to reduce the converter losses due to fewer converter stages, the architecture of the reverse-blocking IGBT and the new switching pattern.