Maximum power point tracking of large-scale photovoltaic array

• Propose the PMCD and BVSD based structure of large-scale photovoltaic array.
• Propose a large-scale optimization algorithm based MPPT method.
• MPPT of large-scale photovoltaic system is achieved under complex conditions.

In partial shading conditions, reverse voltage may impose on the shaded photovoltaic modules and cause the “hot spot” problem. In this paper, a novel topological structure of photovoltaic array is proposed for operational safety and efficiency in possible partial shading, and the maximum power point tracking (MPPT) is also implemented on each photovoltaic module. This new structure consists of the photovoltaic module control device (PMCD) and branch voltage stabilization device (BVSD), which differentiate the MPPT at levels of each photovoltaic module (PVM-level MPPT) and minimum control unit (MCU-level MPPT). The MPPT of large-scale photovoltaic system can be formulized as a large-scale global optimization (LSGO) problem. Therefore, a novel multi-context cooperatively coevolving PSO (CCPSO-m) algorithm is proposed for solving the LSGO. Numerical result shows that the CCPSO-m outperforms some state-of-the-art algorithms evidently, and each photovoltaic module works on its own maximum power point effectively in the proposed structure of PV array. Finally, the large-scale photovoltaic system can achieve PVM-level (or MCU-level) MPPT, conquer the “hot spot” problem, and improve output power under complex environmental conditions significantly.