Control of Three-Phase Grid Integrated Multiple Solar Photovoltaic Arrays-BES Based MG

Abstract

In this article, a three-phase grid integrated multiple solar photovoltaic (PV) arrays-battery energy storage (BES) with a bidirectional converter-based microgrid (MG) system is presented. At dc links of main voltage source converter (VSC) and ancillary VSC, two solar PV arrays are utilized to obtain peak power in cost-effective and proficient single stage configuration through distinct incremental conductance maximum power point (MPP) tracking technique. The individual nonlinear loads are linked in parallel at terminals of VSCs, at the point of common coupling (PCC) and, which facilitate the MG expansion to transfer active power to the grid, and to enhance the reliability of MG in off-grid mode. The main VSC operates through the current control, in the grid interactive mode and during fault in the grid, its shifts transient free to the voltage control in an off-grid mode. At PCC, the voltage control, maintains the frequency and voltage, therefore, the ancillary VSC works with current control. A buck–boost converter is interlinks by BES across the main VSC, which regulates the load levelling and maintains voltage for MPPT at its dc link. In order to improve the dynamic performance of system, a feed-forward constituent of PV array power is utilized in the current control algorithm of VSCs, which also enhances the power quality issues. The MG's performance is found satisfactory for scenarios like, load variation, solar insolation change, load unbalance and during inaccessibility of solar power and the grid. The MG is modeled using MATLAB/ SIMULINK and validated in RT-LAB platform of a real time controller OPAL-RT (OP4510).