SPICE modelling of a complete photovoltaic system including modules, energy storage elements and a multilevel inverter

A SPICE model of a complete photovoltaic (PV) system, including a detailed model of photovoltaic cells, a modified cascaded multilevel inverter, and energy storage elements, is presented. The simulation of the system as a whole allows evaluating readily the effects on its performances of the variation of the component parameters, as well as of the external load, the solar irradiation, and the cell temperature. The global conversion efficiency and the total harmonic distortion (THD) of the output waveform are in particular analysed. The role and sizing criteria of a storage element, such as a capacitor, placed at the PV module output are also analysed for various operating conditions. Experimental tests have been carried out on a custom designed prototype photovoltaic system and compared to those obtained with the simulation model.