A new topology with the repetitive controller of a reduced switch seven-level cascaded inverter for a solar PV-battery based microgrid

In this manuscript, a repetitive control approach for the reduced switch seven-level cascaded inverter (RSCI) is proposed for active and reactive power control with enhanced power quality standard for a solar PV-battery based microgrid. The proposed repetitive control approach is applied for the RSCI and the performance is tested on a grid-connected microgrid integrated with photovoltaic (PV) and battery energy sources. To capture maximum power, a control strategy based on incremental conductance method (I&C) is adapted for optimal maximum power point tracking (MPPT) operation. The battery energy storage system in both charging and discharging mode of operation is controlled by repetitive controlled based RSCI as a support to PV for better power management. To show the feasibility and robustness in operation of the proposed approach, a variable irradiance input to the PV unit is considered. To justify the practical applicability of the proposed approach and to satisfy IEEE-1547 power quality constraints, a LCL filter is selected to minimize the harmonic distortion in the grid side current levels. The improved performance of the proposed technique is justified by presenting comparative simulation results with respect to three-level neutral point clamped inverter (NPC) with proportional integral (PI) controller. By using MATLAB software, the validity of the proposed approach is studied by simulation under constant and varying irradiance condition.