Design and Control of Solar PV - Battery System Feeding AC Network with DG Set Backup

Abstract

This work presents the design and control of PV-battery system feeding power to the AC network with diesel generator (DG) set backup at unity power factor (UPF) and the loads connected at the point of common coupling (PCC). The system improves the power factor of the AC network and the DG set to unity. Furthermore, it reduces the distortion in the currents and voltages of the AC network and DG set as par the IEEE std. 519, if any nonlinear load exists at the PCC. Moreover, it mitigates the intermittency of the PV array generation and the load demand at the PCC during the daytime operation by supplying constant power to the AC network. Hence, the variation in the PCC voltages are reduced. The PV -battery system energizes the load by operating as a standalone system if the AC grid'supply is interrupted. Furthermore, it operates as an uninterrupted power supply (UPS) if the generation of PV array reduces to zero. If the battery bank also discharges, then the DG set is connected at the PCC to energize the load. Hence, the load remains energized in all conditions. Here, the DG set operates at an optimal fuel economy zone to minimize diesel consumption and operational cost. However, it is disconnected as soon as the grid supply recovers or the battery bank charges. Therefore, diesel consumption reduces to the lowest. An extensive simulation study is performed to exhibit the performance and the seamless operation of the presented system when its working mode is sudden changes.