Precise active and reactive power control of the PV-DGS integrated with weak grid to increase PV penetration

Abstract

Significant expansion of PV-grid installations have escalated new problems of PV penetration because of intermittent nature of the PV source and inertia-less interface. In this paper, a novel active and reactive power control scheme for a single stage PV-grid system is proposed to counter the potential PV penetration problems for the futuristic grid with large distributed generation system (DGS) contributions. The proposed work incorporates a PV power control algorithm, which not only facilitates maximum power point tracking (MPPT) but also provides precise PV power control, unlike conventional MPPT schemes. These features significantly overcome power and voltage fluctuations, reverse power flow problems and overvoltage issues, which are considered as major potential PV penetration problems and the main reason for limiting large PV installations. In addition, the reactive power control ability increases the effectiveness of the proposed scheme for feeder voltage profile improvement and utilization of the interfacing power converter. A 3-Ph, single stage PV-grid system is considered with the PV source directly integrated with the DC link of the inverter. The DC link voltage is controlled by the inverter. Detailed analysis, modeling and control design are included and supported by key simulation and experimental results.