Voltage regulation in stand-alone microgrids with storage units : a multi-variable H-infinity control approach
Résumé
This study presents a multi-variable robust control scheme for voltage regulation in a diesel-photovoltaic (PV)-supercapacitor hybrid power generation system operating in stand-alone mode. By applying H-infinity control theory, an H-infinity-based voltage controller is proposed to robustly force the voltage magnitude of a point of common coupling (PCC) such as to satisfy dynamic specifications. A cascaded two-level control structure, where this controller is considered like an upper control level and provides references to classical PI-based current tracking controllers placed on a lower control level, is developed. The specific engineering demands of microgrid (MG) operation are cast into an H-infinity control formalism. Effectiveness of the proposed voltage robust control strategy is demonstrated through a series of closed-loop time-domain simulations carried out in MATLAB®/Simulink®.