Wind turbines output power smoothing using embedded energy storage systems

The ability of an energy storage system to improve the performance of a wind turbine (WT) with a fully rated converter was evaluated, where the energy storage device is embedded in the direct current (dc) link with a bidirectional dc/dc converter. Coordinated dc voltage control design of the line-side converter and the energy storage dc/dc converters was proposed using a common dc voltage measurement for smoothing the output power. A transfer function and Bode diagram were introduced to analyze the system performance with different control parameters. MATLAB/Simulink simulations are presented to demonstrate the effectiveness of the proposed methods. It was found that the proposed methods smooth the power output from the WT to the grid and thus improve the quality of the generated power.