Power collection and integration on the electric grid from offshore wind parks

Abstract

There is a lot of potential in offshore wind parks due to the amount of available area. The parks get bigger in size and will continue to grow in the future. In this article a new converter topology for offshore wind parks is proposed. This topology is meant to be for large offshore wind parks sited far from shore and it is based on DC collection and transmission. All the converters are located in the nacelle of the wind turbines and the turbines are connected in series directly connected to shore without any 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 1-phase AC converter, a high frequency high power transformer and a full-bridge converter. The AC-AC converter has a new type of 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 reduces the converter losses due to fewer converter stages, the architecture of the reverse-blocking IGBT and the new switching pattern.