Transient Response Enhancement in an AC Microgrid Using a Simple Two-Stage Controller

This paper addresses a modified PI controller for a grid-forming converter in an islanded microgrid. The proposed control technique uses a two-stage strategy, one plus propotional-derivative with propotional-inegral ((1+PD)+PI) controller, which can reduce the effect of high-frequency noise caused by the converter switching. Simulation results for a grid-forming converter in an islanded microgrid confirm the performance and effectiveness of the proposed control method. It is shown that the proposed controller can improve transient stability much better compared to the well tuned single PI controller. Implementing this method does not increase the complexity of the system, and the performance is more superior than the conventional primary controller, which can be considered as the main benefit of this method.