Voltage Quality Improvement and Power Management of Islanded AC Microgrids with Variable Loads and Sources

To tackle the ever-increasing energy demand, microgrids (MG) with higher penetration of renewable energy sources (RES) serve as an effective solution. Since these sources are highly intermittent, various maximum power point tracking (MPPT) algorithms and energy storage system (ESS) is utilized to exploit the full potential of the resources and operate reliably. This paper focuses on the power management and voltage quality improvement of an AC microgrid with solar, wind energy generation, and battery energy storage. The variable step incremental conductance (INC) MPPT algorithm is used for solar and wind distributed generations (DGs). The ESS maintains the power balance and the DC bus voltage, which is interfaced through PI controlled bi-directional DC-DC converter. The voltage quality at the AC bus is improved by employing finite control set model predictive control (FCS-MPC) of a three-phase three-level neutral point clamped inverter. The results elucidate that harmonic distortion and unbalance in the AC bus voltage are compensated under varying load and source conditions. Furthermore, the power-sharing capability of the inverters with two DGs is investigated.