Sliding mode control for a grid-connected wind turbine with asynchronous generator

In this paper, a sliding mode control is proposed to control a large wind turbine (3 MW). Sliding mode control is considered more robust than the linear controllers. The complete model of the conversion system of wind energy is established. It includes a wind turbine, a gearbox, a variable speed squirrel cage asynchronous generator, two PWM converters, DC bus circuit and the filter. The side-generator converter is used to generate the maximum power from Wind Turbine Generator. Then, the control strategy, which combines maximum power point tracking and a pitch control, is given. The grid side converter is used to maintain the DC link voltage constant, to achieve unity power factor, and injects the generated power into AC network. The models and control schemes are validated through simulations by using MATLAB/ Simulink environment. The results of simulation show that the proposed control is efficient and gives good performance.