Distributed Virtual Inertia Control for Frequency Regulation in Islanded Microgrids

─ In the absence of synchronous generator, distributed energy resources such as solar or wind generations need to provide inertia support to guarantee stable operation of a low-inertia islanded AC microgrid. This paper proposes a distributed method to regulate the system frequency by emulating the behavior of a conventional synchronous generator in term of virtual inertia control, using the coordination of both reserved active and reactive power of distributed energy resources. This paper proposed a multi-layer hierarchical control structure for MGs, using consensus algorithm and Andronov-Hopf based Virtual Oscillator Control. The proposed method, besides providing advantages of conventional AHO over well-known droop control method, is able to eliminate the frequency deviation and improves the system frequency response, while maintaining accurate load power-sharing among DERs in proportion to their rated power regardless of the line impedance nonuniform and network topology. An important feature of the proposed method is that it coordinates both reserved active and reactive power output of DERs to provide frequency regulation, reducing the need of high active power utilization during the inertia response. Therefore, the proposed method is more economical meaningful. The numerical simulations in Matlab/Simulink validate the effectiveness of the proposed method.