Abstract:
The frequency control of the traditional virtual synchronous generator(VSG) is differential control, and the introduction of virtual inertia causes the VSG to exhibit a second-order oscillatory characteristic, leading to the issues of frequency deviation and active power overshoot when subjected to load disturbances in an island microgrid. To address these issues, a frequency deviation-free coordination control method for multiple VSGs is proposed, one which includes two parts: frequency deviation-free regulation control with precise active power allocation and damping improvement control. By using the “communication” effect generated from a globally consistent bus frequency, the proposed control method coordinates the various VSGs within the system in a decentralized manner, actively eliminating microgrid frequency steady-state deviation, ensuring that each VSG shares the active power load according to its capacity, and suppressing the active power overshoot. Finally, the effectiveness of the proposed control method is verified through simulation and experiment.