Microgrid Frequency & Voltage Adjustment Applying Virtual Synchronous Generator

Abstract

The distributed generations (DG) are linked to microgrids (MGs) by power converters regularly and the MG will be in mutual interconnection with conventional power systems. The more the participation level of the converter-based DGs in the MG, the more the stability issues are seen in the MG. Unlike conventional synchronous generators (SGs) which have considerable inertia, the converter-based DG units lack this intrinsic inertia; therefore, they potentially make the MG prone to stability issues. The idea to emulate the behavior of SGs in the control loop of interfaced converters to maintain the MGs stability is a newly-growing idea. This paper tends to propose an improved voltage and frequency control strategy for island MGs consisting several converter-based DGs. The proposed control structure uses an advanced Virtual Synchronous Generator (VSG) model and aimed at implementing the primary frequency and voltage control of MGs. The designed model considers both resistive and inductive parameters of lines in MGs. Since the suggested control structure is a local one, doesn't require communication links between DG units. The simulation results verify the potency of the recommended control structure to preserve the frequency and voltage stability of an island MG even in severe events.