A Piecewise Function based Equivalent Aggregation of Photovoltaic Array Considering Partial Shading Situation

Photovoltaic (PV) grid-connected system is a complicated project which is composed of large numbers of PV cells with different series and parallel connection and relating power electronic converters. To simplify it, the equivalent model of PV unit is essential to build. Thus, the paper proposes an equivalent aggregation model of PV array based on piecewise function. By building the typical industrial mathematic model of PV cell and analyzing the working mode of PV cells with series connection, a unified expression of output voltage and current of PV array based on piecewise function is determined. The proposed model is suitable for PV array either in normal or partial shading conditions and brings certain simplicity in calculation. The simulation in Plecs platform verifies the correctness and effectiveness.