Real time simulation of renewable sources by model-based control of DC/DC converters

This paper presents a DC/DC buck converter circuit for real-time laboratory simulation of renewable sources. The DC/DC converter, suitably driven, can accurately describe the current-voltage characteristic of a photovoltaic (PV) array and of a fuel cell (FC). In perspective its hardware structure, if the source modelling is correctly known and implemented, can reproduce any renewable source with rated data compatible with those of the DC/DC converter. The I-V laws of the PV and the FC have been obtained by an appropriate modelling of the considered renewable sources. Particular care has been given to the design of the converter control, to ensure the desired stability and dynamics. It has been verified in numerical simulation and experimentally that the designed DC/DC buck converter is able to reproduce the electrical characteristics of the experimental generator both in steady state and transient conditions, due to either load or parameters variations. The effectiveness of the proposed circuit is verified by laboratory experiments, obtained by implementing the converter control on a low cost DSP board.