Solid state transformer controller and it's interfacing with wind energy conversion based distribution systems

Abstract

As the fluctuations of wind energy is increases in the WECS, 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. So to provide controlling action Solid State Transformer (SST) Controller is proposed in this paper. This paper presents the Control strategy of 3 phase SST controller, including for the AC/DC Rectifier Stage, Dual Active Bridge (DAB) Converter Stage and DC/AC Inverter Stage. Based on the d-q axes vector controller, a novel control strategy is proposed to balance the rectifier capacitor voltages and the real power through the DAB parallel modules. to this end, a simulation study for WF driven by Squirrel-Cage Induction Generators (SCIG) is presented to verify the effectiveness of the proposed system. Here Simulation test cases using MATLAB-Simulink are implemented on a 6 MW wind farm exports a power to 120 KV grids. The study is carried out for the two cases such as, Conventional transformer interfaced with WECS. and for the Solid State Transformer (SST) interfaced with WECS. The simulation result shows the influence of variations in Wind Speed on Active & Reactive of power WF and on PCC Voltage. SST performs the typical functions of Active Power Transfer, Reactive Power Compensation and Voltage conversion in Wind Energy Based distribution System.