Energy Management and Control of Single-Stage Grid-Connected Solar PV and BES System

Abstract

In general, Solar Photovoltaic (SPV) is integrated to grid through a DC-DC converter and Voltage Source Converter (VSC) for real power injection (called two-stage conversion). In view of efficiency point, the single-stage conversion becomes popular and in which Maximum Power Point Tracking (MPPT) of SPV and real power injection are achieved with VSC alone. But, if Battery Energy Storage (BES) supported by bidirectional DC-DC converter is presented in the single-stage conversion system, then co-ordination between DC-DC converter and VSC is required to achieve simultaneous operation of MPPT and real power injection. In this paper, a co-ordinated control of single-stage grid connected SPV and BES system is proposed along with energy management. In which, the algorithm coordinates VSC and bidirectional DC-DC converter based on the State of Charge (SoC) of the battery such that MPPT and power injection is achieved simultaneously. The proposed method not only injecting real power, but also works to compensate load reactive power and unbalanced neutral current minimization. Further, an active rectification operation during non-SPV hours is discussed for better utilization of VSC capacity. The multi-functional features of the proposed method are explained using simulation studies and are also validated through experimental studies.