Hierarchical energy management and control to improve the reliability and efficiency of wind farms connected to the grid

This article proposes hierarchical power management and energy control aimed at improving the reliability and efficiency of electric power generation from a wind farm connected to the grid. The wind farm consists of three wind energy conversion systems (WECS) each consisting of a wind turbine, a double-feed induction generator and five-level power converters. The first control layer includes a maximum power point tracking algorithm to extract the maximum power from the wind energy source based on an optimal torque control strategy. The real and reactive power flow from the WECS to the grid is controlled with a non-linear backstepping controller based on the Lyapunov stability theory. Finally, a DC bus voltage controller with a clamping bridge is employed to ensure the stability of the DC bus voltage and to compensate for transient disturbances caused by load fluctuations. The second layer of control ensures coordination between the wind farm, the power grid and the load to ensure reliable and efficient power supply. The model of the grid-connected wind farm and the proposed control scheme are developed using MATLAB and Sim Power Systems Toolbox. A series of simulation scenarios are presented to evaluate the performance of the proposed control scheme under various operating conditions.