Multi-level PO MPPT control PV system considering shadow influence

This paper proposes the multi-level (ML) PO MPPT control of the photovoltaic (PV) system considering shadow influence. The output characteristics of the solar cell are a nonlinear and affected by a temperature, the solar radiation and shadow influence. Particularly, PV module integrated converter (MIC) system is very sensitive to the shadow influence because the capacity is very small. In order to increase an output and efficiency of the solar power generation, the maximum power point (MPP) control are necessary. Conventional constant voltage (CV) perturbation and observation (PO) and incremental conductance(IC) are the method finding MPP by the continued self-excitation vibration. The conventional MPPT control is unable to be performed when output is rapidly changing by shadow influence. To solve this problem, the new control algorithm of the MLPO in which the step value changes by output change is presented. The proposed algorithm compares the output error of the conventional control algorithm with the solar radiation, a temperature and shadow influence. In addition, the validity of this algorithm is proved through the response characteristics of the output error.