A Novel Control Strategy to Integrate DSTATCOM Functionalities in a Grid-Connected AC Microgrid, Featuring SPV-BES and SyRG-Wind-Based DGs

Harmonics drawn by loads degrade power quality performance of a microgrid (MG). Equipping MG with distribution static compensator (DSTATCOM) functionalities can mitigate this issue. The effectiveness of DSTATCOM relies heavily on method used to filter load currents, and an optimal algorithm offering superior filtering, dynamic response, and dc offset rejection is still under research. This work introduces a novel fourth-order generalized integrator (NFOGI)-based harmonic decoupling network (HDN) for extracting load current and grid voltage sequence components. These components are utilized to integrate DSTATCOM functionalities into an MG, comprising a solar photovoltaic array (SPVA), battery energy storage (BES), and a synchronous reluctance generator-based wind generator (WG). SPVA and BES form a solar photovoltaic system (SPVS) sharing a grid-side power converter (GSC), while WG connects to ac grid through a separate back-to-back GSC, creating a wind energy system (WES). DSTATCOM features in both SPVS and WES are meticulously controlled by developed novel control strategy to ensure balanced current injection by SPVS, even under unbalanced loads. This approach keeps SPVS’ dc link free from 2nd harmonics and enables direct BES integration at dc link without compromising its lifespan. Results demonstrate that the proposed algorithm provides a superior response, ensuring MG compliance with the IEEE standard power quality indices (PQIs), such as THD and unbalance factor.