Second-Order-Continuous Sliding Mode Control of a Wind Turbine driven a DFIG using Matrix Converter

The present study focuses on the variable structure control of a Doubly-Fed Induction Generator (DFIG) integrated through a three-by-three matrix converter ([3×3]MC) within a grid-connected wind turbine system. Initially, we developed a [3×3]MC topology to ensure power flow between the DFIG and the network. This configuration, devoid of an intermediate DC-Link, offers advantages over the conventional setup of Rectifier/DC-Link/Inverter. To achieve straightforward control of the [3×3] MC, it's beneficial to conceptually divide it into two parts. The first acts as a rectification stage, ensuring a stable virtual DC-Link, while the second serves as an inversion stage, producing output voltages that can vary in both amplitude and frequency, akin to a typical inverter. For the exchange of active/reactive power between the DFIG and the grid, we enhanced a second-order continuous sliding mode control (SOC-SMC) strategy and applied it to generate voltage commands for the [3×3]MC. The entire system underwent simulation using a 7.5 KW wind turbine driven by a DFIG within Matlab/Simulink. Satisfactory performance was demonstrated by the proposed system.