Decentralized composite generalized predictive control strategy for DC microgrids with high PV penetration

High PV penetration into DC microgrids could bring serious stabilization challenges for power electronics engineers, as renewables are accessible to DC bus voltage oscillation, hence leading to degradation of power quality and even system collapse. This article addresses the stabilization issue for a DC microgrid with high PV penetration rate, in which a decentralized composite generalized predictive control strategy is designed. First, a disturbance observer is designed to deal with the lumped uncertainties of both PV intermittency and variation of constant power loads, which is subsequently integrated into the control design through feedforward compensation loops. Second, an offset-free generalized predictive controller is designed by employing the receding-horizon optimization process. In this regard, the new method could endow the DC microgrid system of two main distinguishable features: (1) large-signal stability for global system; (2) optimized transient-time control performance based on an offset-free voltage regulation objective. The effectiveness and performance improvement of the proposed methodology are verified by comparative experimental studies on a DC microgrid platform with 50% PV integration.