Control of a Grid-connected Wind Turbine with Quasi-Z-Source Inverter

Typically, grid-connected wind turbines equipped with permanent magnet synchronous generator (PMSG) present a back-to-back power converter based on voltage-source converters. In this paper, this structure is modified using an uncontrolled rectifier for the AC/DC conversion in the generator, and a quasi-Z-source inverter (qZSI) at the grid side. The qZSI is an attractive solution to boost and convert DC voltage to AC in a single stage. The main objective of the paper is the application of a qZSI for large grid-connected wind energy systems. In this configuration, active and reactive powers can be controlled through a Space Vector Modulation technique adapted for Z-source converter. Simulations were performed using MATLAB/Simulink® with wind and load variations to confirm the proper functioning of the proposed controllers. The results showed satisfactory responses of the proposed 5 MW PMSG-driven grid-connected wind turbine.