When coupled with the appropriate controller, a battery energy storage system (BESS) is the most effective energy storage technology for diminishing system fluctuations due to atmospheric and meteorological variabilities. This work proposes DC and AC side controllers, for a hybrid wind-PV-BESS connected to the grid, based on Takagi Sugeno-Fuzzy Logic Controller (TS-FLC). When unbalanced loads are connected to the Point of Common Coupling (PCC), the suggested inverter controller helps balance grid currents, reduce harmonics caused by non-linear loads, and compensate for reactive power demand by the load. The same inverter may provide active power to the grid and act as a maximum power point tracker (MPPT) as the battery’s State of Charge (SoC) reaches its maximum, so a separate converter is not necessary to get the maximum power. TS-FLC controller in various case scenarios have been tested using MATLAB and is compared to the Proportional Integral (PI) controller. Though both controllers work effectively but TS-FLC has an extra edge over PI controller and Mamdani Fuzzy controllers as per IEEE-519 standard. TS-FLC is capable of reducing source current harmonics up to 0.08% (steady - state) and 0.10% (with fault), while source current harmonics reduction with PI controller is comparatively much higher.