Decentralized secondary control for frequency restoration and power allocation in islanded AC microgrids

•The main highligts of our manuscript are summarized as follows.•The proposed communication-free secondary control can achieve frequency restoration and active power sharing within a tolerable deviation, which im-proves the system reliability.•Our proposed control algorithm is much simple and thus easy for imple-mentation.•The proposed approach can allocate active powers flexibly according to the desired optimal power ratio determined by tertiary optimization.•The stability of the overall system is rigorously proved by the Lyapunov stability theory. Also, the effectiveness of our controllers is verified by real-time experimental results.