Ultracapacitors utilization to improve the efficiency of photovoltaic installations

•The efficiency of a PV installation in low irradiance periods was improved.•We simulated the MODEN system in five European locations.•We apply MODEN efficiency improvement system to a real photovoltaic plant.

This paper proposes an Energy Modulation strategy (MODEN) which allows the PV inverters efficiency to be incremented in low input power condition. The key element is the utilization of an ultracapacitors bank as energy regulation transitory element: in low irradiance condition, the energy coming from the PV array is not converted immediately, but temporary stored to be converted at a power regime in which the inverter may have maximum yield. In this paper the simulator developed, the guidelines for the MODEN system design optimization, and the simulation results, are described. It is also described the prototype fabricated and installed in a PV plant, and its performance evaluated.