A Reduced DC-Link Voltage-Based NSC Topology for an On-Grid PEMFC Microgrid Capable of Handling Unbalanced Load Conditions and Grid Disturbances

This article presents a nine-switch converter-based on-grid proton exchange membrane fuel cell microgrid system and its control with a reduced DC-link voltage requirement for the NSC. With the proposed topology, the do link voltage requirement of the NSC could be reduced by nearly 33%. Apart from the DC link voltage reduction, this work proposes a minimum voltage injection-based control scheme, which helps achieve the claimed voltage reduction. This work has also proposed a self-tuned filter-based modified indirect current control scheme, which ensures a balanced grid current during unbalanced load conditions. The proposed system is evaluated under various grid and load-side disturbances. The performance of the proposed system, along with its associated control structures, is studied under nearly 28% grid voltage sag and 10% swell. The control structure delivers a constant load voltage and a steady grid power flow during grid voltage sag and swell. The proposed system also performed efficiently during load and generation side disturbances Such as load change, change in active power, and reactive power references. During unbalanced load conditions, the proposed modified indirect current control scheme effectively compensated for the load imbalance and resulted in balanced grid currents. The whole system is mathematically modeled in the Matlab/Simulink platform, and the system’s performance is validated using an OPAL-RT 4510 real-time platform.