Laboratory PV generator for MPPT dynamic response testing

A laboratory PV generator is presented in this paper, whose target application is the dynamic test, in controllable conditions, of MPPT algorithms or circuits. The system comprises three main components: a solid state lamp, its power supply and control electronics, and a PV module. The instrument uses the controlled light emission of the solid state lamp to induce photogeneration in the PV module. The LED drivers are designed so that the incident radiation intensity can be modulated within a relatively large bandwidth (in the kHz range). Thus, the PV module power output can be precisely controlled and, in particular, relatively rapid and pre-determined variations can be induced. These features allow the implementation of repeatable dynamic tests of any converter connected to the PV module and, in particular, of its built-in MPPT strategy. From this standpoint, the instrument outperforms both existing optical solar simulators, e.g. based on gas discharge or incandescent lamps, and electrical simulators, based on suitably controlled power supplies. Indeed, the former offer very limited dynamic performance, the latter only replicate the static PV generator characteristics. To prove the effectiveness of the instrument, a ripple correlation MPPT strategy is tested. Experimental results are presented.