Variable structure control approach for grid connected PMSG Wind Farm

The study of a Wind Farm (WF) based on Permanent Magnet Synchronous Generator (PMSG) and interconnected to the electric network is presented. The 8 MW wind farm consists of 4 PMSGs based 2 MW generators connected to a common DC bus. Each generator is connected to the DC-bus with a rectifier while the DC-bus is connected to the grid through one DC/AC converter. The proposed control law combines Sliding Mode Variable Structure Control (SM-VSC) and Maximum Power Point Tracking (MPPT) control strategy to maximize the generated power from Wind Turbine Generators (WTGs). Moreover, considering the variation of wind speed, both converters used the SM-VSC scheme. The PMSGs side converters are used to achieve MPPT, while the grid-side converter regulates DC-link voltage and injects the generated power into the AC network. Accordingly, WF system not only can capture the maximum wind energy, but also can maintain the frequency and amplitude of the output voltage with unity power factor. The effectiveness of the control strategy is verified by simulation analyses using Matlab/ Simulink.