Energy Storage Integrated Solar PV Arrays Based Microgrid Control Unified to 3P4W Grid

Abstract

This work presents a new control for a battery energy storage (BES) integrated solar photovoltaic (PV) arrays-based microgrid (MG) synchronised to the three phase four wire (3P4W) grid. The maximum power is obtained via two PV arrays through distinctive maximum power point (MPP) tracking technique. A boost converter is utilized to connect the first PV array at the main voltage source converter (VSC) DC link, where a BES is also linked to it. In the single stage topology, the second PV array's output is integrated directly at ancillary VSC's DC link. The main VSC's control approach is based on the current control technique under the grid interactive mode and during the grid discontinuation, it shifts to the voltage control approach under an islanded mode of operation. The rating of MG is enhanced as the terminals of each VSC in parallel, are connected at the point of common coupling (PCC). The nonlinear loads are integrated VSC's terminals. The solar power is fed to the grid in the grid interactive mode and the system's operational reliability is enhanced in the standalone mode. The main VSC's dual mode smooth control is implemented via the power electronics switch. At PCC, the main VSC voltage control, sustains the frequency and voltage, therefore, the ancillary VSC's, operation is always with the current control. An incessant power is distributed to the load side. The utilization of PV array power feed-forward term in the current control of VSCs enhance the dynamic performance. The system compensates the neutral current and takes care power quality concerns i.e. alleviation of current harmonics and power factor improvement. In the MATLAB environment, the microgrid behaviour is perceived satisfactory under steady state and dynamic circumstances such as, solar power perturbation, load unbalance and load perturbation.