One-shot SPICE simulation of photovoltaic modules, storage elements, inverter and load

A SPICE model of a complete photovoltaic (PV) system, including a detailed model of PV cells, a modified cascaded multilevel inverter, energy storage elements and load, is presented. Multi-level inverters suits particularly well PV systems and bring several advantages among which the lower switching speed of the switching elements, which in turn means less stress for these devices and a lower harmonic content in the output voltage. The simulation of the system as a whole allows evaluating readily the role of components, as well as of the solar irradiation and cell temperature. The global conversion efficiency and the total harmonic distortion (THD) of the output waveform are in particular analyzed. The role and sizing criteria of a storage element placed at the PV module output are also analyzed for various operating conditions. Experimental tests have been carried out on a photovoltaic system prototype and compared to those obtained with simulations.