Real-Time Voltage Control and Harmonics Elimination of Islanded Microgrid Using Back-to-Back Electric Spring

Renewable energysources (RESs) based islanded microgrid structure is susceptible to voltage and frequency fluctuations. The 'Electric Spring' (ES) stands out as a highly effective solution for strengthening operational flexibility and seamlessly integrating RESs. This paper presents a unique concept of combining the three phase Back-to-Back Electric Spring (BTBES) control topology to Self-Excited Induction Generator (SEIG) which supplies power to Critical Load (CL) and Non-Critical Load (NCL). The series inverter of BTBES is used to maintain constant voltage profile across the CL during system imbalance using 'in-phase' compensation method. The shunt-connected inverter upholds the series inverter by keeping constant DC link voltage. This shunt inverter mitigates the current harmonics of the microgrid arising due to non-linear loading by current control loop with Hysteresis Band Current Controller (HBCC). The validation of BTBES effectiveness under various linear and non-linear load variations on both CL and NCL side demonstrates system's resilience to changing load conditions. The paper effectively integrates theoretical analysis, MATLAB simulation studies, and experimental validation through Real time power Hardware-in-Loop (HIL) testing to present a thorough evaluation of the BTBES control. This integrated approach used in this paper ensures credibility and applicability of the proposed BTBES in an islanded microgrid system.