Hierarchy control of power quality for wind - battery energy storage system

Uncertainty of the wind results in a fluctuating power output of wind turbine generators, and consequently, causes adverse impacts on the stability of system frequency and voltage. To smooth such power fluctuation, this study proposes a power quality control strategy based on a three-level hierarchical structure for wind - battery energy storage hybrid power system, including grid demand calculating level, energy management level and voltage-source converters control level. The advantage of the control strategy is that the state of charge of a battery energy storage system is regulated within proper range and the voltage at the point of common coupling is kept stable while smoothing wind power. Effectiveness of the proposed method is validated by MATLAB/SIMULINK simulations and experiments.