Architectural and design issues on optimal management of photovoltaic pumping systems

Unconventional design and control techniques for the optimal utilization of photovoltaic energy sources are discussed. The application domain considered concerns photovoltaic pumping plants. A design methodology for plants characterized by direct connection of the load to the generator is illustrated, leading to easy selection of components and proper sizing of the energy source to meet assigned target specifications. A direct coupling matching technique based on the reconfiguration principle of generator geometry is presented. This guarantees transfer of the maximum available power from the source to the load in all environmental and working conditions. A hierarchically structured control system has been conceived for automatic and flexible plant management: at the lower level a microcomputer, equipped with the necessary process interfaces, handles execution of real-time control tasks while a personal computer carries out supervision, monitoring, and diagnostic activities at the higher level. Both simulation studies and experimental tests demonstrate the validity of the techniques as well as the superior performance achievable in comparison with traditional solutions