Solid state transformer interfaced wind energy system with integrated active power transfer, reactive power compensation and voltage conversion functions

As the power of wind energy system increases, the control of their active and reactive power becomes increasingly more important from a system standpoint given that these are typical frequency and voltage control parameters. In this paper a family of wind energy systems with integrated active power transfer, reactive power compensation and voltage-conversion functionality is proposed. The proposed wind energy systems using solid state transformer (SST) can effectively suppress the voltage fluctuation caused by the transient nature of wind energy without additional reactive power compensator and as such may enable the large penetration of wind farm (WF) into the distribution system. To this end, a simulation study for WF driven by squirrel-cage induction generators is presented to verify the effectiveness of the proposed system. In addition, a modular type high voltage and high power three-phase SST topology is presented for the proposed system, and its basic building block, which is a single-phase SST, is analyzed. The function of SST in the presented wind energy system is verified in a single-phase laboratory prototype with scaled down experiments.