Battery Management and Operation of a Wind-PV Based Microgrid

Abstract

This paper deals with an integrated PV (Photovoltaic)-wind battery-based micro-grid with an improved multi-functional grid-side converter (GSC) control. This improved discrete three-stage reduced-order multiple integrator (ROMI) GSC control is used to maintain the reactive power into the grid as well as to maintain the dc-link voltage across the converter. Moreover, it improves power quality issues in different abnormal conditions. The rotor side converter (RSC) is used to provide the required amount of reactive power using the field-oriented control, for the wind power generator (WPG). A double fed induction generator (DFIG) is used as a WPG. The single-stage PV array and a battery with class-C chopper is connected to the common dc-link of the GSC. It extracts the maximum power from wind turbine in light load conditions. The tip speed ratio (TSR) algorithm is used to extract the maximum power from a wind turbine and the incremental conductance (INC) method is used to extract the maximum power from a PV array. According to the load demands at the micro-grid, the battery management works. A PV feed-forward term is added with the total active component of the GSC control, which damps out the dynamic changes into the system. The grid current THD is also maintained within 5% according to the IEEE standard. Simulated results show the performance of the microgrid in different conditions, such as speed changes from the cut-in to cut-out the speed of the wind turbine, load unbalancing condition, changes in PV insolation. The charging and discharging cycle of the battery is optimized using at battery management system (BMS) at different circumstances.