Stability Analysis of a Grid-connected Large-scale DC Microgrid with a Hybrid Wind/Solar Farm

Abstract

Stability performance of a grid-connected largescale DC microgrid (DCMG) with a hybrid wind farm (WF) and solar farm (SF) is evaluated in this paper. The studied DCMG comprises an equivalent aggregated (EA) SF and an EA WF based on permanent-magnet synchronous generator (PMSG). The AC output of the EA WF is transformed to a DC quantity through an EA voltage-source converter (VSC), which is integrated with the DC output of the EA DC-DC converter of the EA SF. The DC quantity of the DCMG is transformed to an AC quantity to send to an AC power grid through an EA voltage-source inverter (VSI), a step-up power transformer, and transmission lines. Small-signal stability of the studied DCMG under various chosen operating points is achieved using eigenvalue analysis. Dynamic simulations and transient responses of the studied DCMG under various disturbances are also completed and evaluated.