Comparative Study of Different Controllers for Offshore DC Microgrids

DC microgrids (MGs) are emerging as an appealing option for the supply of reliable and efficient power to offshore industries because of their capacity to incorporate a variety of distributed energy resources (DERs). This is possible due to the advancements in power electronics technology, which play a fundamental role in enabling the operation of DC MGs. Crucially, the effective functioning of each power converter in a DC MG relies on a well-designed controller that can maintain DC voltages within specified limits. Furthermore, the controller ensures the system's reliability and stability in the event of any disturbances. However, designing an effective control system for DC MGs poses significant challenges, owing to the inherent variability and intermittent nature of many DERs and load variations. Hence, a suitable and well-tuned controller for each power converter is required to ensure stable and reliable operation. In this paper, a comparative study of four control schemes proposed for DC MGs is presented: Proportional-Integral-Derivative (PID) voltage-mode control, PID-based cascaded control, cascaded average current-mode (ACM) control, and sliding mode control (SMC). The performance parameters of each controller are assessed through the electromagnetic transient (EMT) simulation. The SMC approach has been identified as the most suitable control strategy to use for the DC MG model.