Power hardware-in-the-loop validation of primary frequency robust control in stand-alone microgrids with storage units

This paper describes a multi-variable robust control scheme for frequency regulation in a diesel-photovoltaic-supercapacitor hybrid power generation system operating in stand-alone mode. The proposed control structure relies on a two-level architecture, with conventional PI-based current tracking controllers placed on the lower control level and receiving references from an H-infinity-control-based upper level. The specific engineering demands of microgrid operation are cast into an H-infinity control formalism. A rapid-prototyping test bench composed of a real supercapacitor-based energy storage system and an emulated diesel-photovoltaic-load grid is developed using real-time digital simulators, namely RT-LAB (R) and dSPACE (R), in order to experimentally validate the proposed frequency robust control strategy under realistic operating conditions.