Replacing the Grid Interface Transformer in Wind Energy Conversion System With Solid-State Transformer

Abstract

In wind energy conversion systems, the fundamental frequency step-up transformer acts as a key interface between the
wind turbine and the grid. Recently, there have been efforts to replace this transformer by an advanced power-electronics-based solid-
state transformer (SST). This paper proposes a configuration that combines the doubly fed induction generator-based wind tur- bine
and SST operation. The main objective of the proposed con- figuration is to interface the turbine with the grid while providing enhanced operation and performance. In this paper, SST controls the active power to/from the rotor side converter, thus, eliminating the grid side converter. The proposed system meets the recent grid code requirements of wind turbine operation under fault condi- tions. Additionally, it has the ability to supply reactive power to the grid when the wind generation is not up to its rated value. A detailed simulation study is conducted to validate the performance of the proposed configuration.