Operation of Battery Aided Grid-Connected CHB Inverter Under Asymmetric PV Power Conditions

Cascaded H-bridge (CHB) inverter is a good fit for grid-connected photovoltaic (PV) applications because of its benefits like modularity, fault tolerance, and low current distortion etc.,. However, uneven power generation, called as power imbalance, is one of the frequent problems encountered by the CHB inverter fed PV system. Power imbalance causes the h-bridge modules (HBM) with high PV power to overmodulate and worsens the distortion of the grid current. Despite the increase in the modulation region to 4/π with the use of existing harmonic compensation techniques, a need for higher modulation index (MI) arises because of severe power imbalance in the system. Hence, a battery aided approach for the CHB inverter fed PV system is presented in this paper to improve the utilization of PV sources and nullify the severe power imbalance in the system and the proposed approach is validated with the help of simulation studies.