Coordinated Control Strategy of Battery Energy Storage System and PMSG-WTG to Enhance System Frequency Regulation Capability

A novel inertial control method based on the torque limit control (TLC) is proposed in this study for the purpose of maximizing the temporary inertial response of permanent magnet synchronous generator-wind turbine generator (PMSG-WTG) over a wide range of variable wind speed conditions. To eliminate the secondary frequency drop issue during the rotor speed restoration, a small-scale battery energy storage system (BESS) is utilized by adopting the coordinated control strategy between BESS and PMSG-WTG. For the sake of minimizing the excessive use of BESS energy, this control strategy can smoothly discontinue the participation of BESS once the system frequency restores to the specified value. The simulation results conclude that the overall system frequency regulation performance can be significantly improved through such coordination control of BESS, PMSG-WTG, and conventional generators for the enhanced inertial response under different wind power penetration levels as well as variable wind speed conditions. Furthermore, the potential impact of TLC on the mechanical structures of wind turbine throughout the inertial response is investigated by using the CART2-PMSG integrated model.