Distributed Cooperative Voltage Control for Grid-Following and Grid-Forming Distributed Generators in Islanded Microgrids

In island microgrids, to tap the voltage control potential of different DGs, this paper presents a unified distributed cooperative voltage control approach for grid-following (GFL) and grid-forming (GFM) DGs. The proposed approach consists of a unified modeling method and a novel range-consensus-based distributed control algorithm. The modeling method employs power coupling and extended state observer (ESO) to unify different inner dynamics and control structures of DGs, making the voltage regulation of different DGs can be addressed by designing the same distributed controller. The proposed distributed algorithm introduces deviation-based states to converge the voltages to an expected range instead of a consensus state, making the algorithm is more in line with the voltage control standard of the grid code than the common state consensus ones. Besides, the local feedback designed in the algorithm improves the anti-interference ability of the system. The Lyapunov technique verifies the stability of the proposed method. Finally, the effectiveness of the proposed scheme is validated by several simulation results and a hardware-in-the-loop (HIL) test.