An adaptive control strategy for VSG with reduced size energy storage system

Abstract

It is well known that distributed generators (DGs) based on virtual synchronous generator (VSG) control can suppress the deviation in frequency with the help of generated virtual inertial and droop power. However, previously proposed methods are generally based on the assumption that the energy storage system (ESS) can provide unlimited power for the VSG. Hence, the implementation of such VSG strategies requires a relatively large ESS, which is one of the critical limiting factors for the growth of VSGs in the power system. This paper proposes a novel adaptive control for VSG with reduced-sized energy storage. The results verified by simulation in PSCAD/EMTDC have shown that the proposed scheme can limit the power usage from the ESS to only during the transient state. Contrastly, the power output from the ESS slowly reaches zero during the steady-state, allowing a reduced-size ESS utilization with the VSG control. The proposed control can also increase the settling time that the VSG needs to reach its new steady-state, thus, giving synchronous generators' slow responsive secondary frequency controllers enough time to intervene if required.