Operation of Multiple PVs and BES Microgrid With Neutral Current Compensation and Reactive Power Sharing Between VSCs at Different Scenarios

Solar photovoltaics (PV) must be integrated with energy storage units to override power intermittent. This paper uses a battery energy storage unit interfaced using a three-phase, four-legged voltage source converter (VSC) to provide unbalanced and neutral current compensation to the local loads and override solar PV intermittency. The effect of neutral current compensation on DC-link voltage limit of the VSC is analyzed, and different strategies for compensation for the reactive and harmonic demand of local loads under various operating conditions are discussed. The microgrid under consideration consists of a central BES and four solar PV arrays interfaced to point of common coupling (PCC) using separate VSCs. A third-order generalized integrator-based frequency locked loop (TOGI-FLL) is used to determine the harmonic components of load currents. The functioning of proposed control strategy during the presence of highly non-linear, reactive, unbalanced three-phase and single-phase local loads is validated using simulation and OP5700 based real-time test bench setup.