Preventive-Resilient Algorithm Based on Weighted Bandwidth Method for Stable Load Management in Zonal DC Shipboard Microgrids

The most advanced DC shipboard power systems will be based on the wide deployment of controlled converters in a zonal distribution configuration. On one side the power electronics arrangement enables advantages for the onboard functioning (e.g. flexibility, redundancy and adaptability), on the other it can open worrying issues on DC system stability. When perturbing a negative-damped DC power grid, the incoming instability triggers a ship blackout as a consequence. To avoid this catastrophic eventuality, the Power Management System (PMS) is programmed for the smart real-time adaptation of converters bandwidths. The paper presents a Preventive-Resilient (P-R) bandwidths tuning to guarantee the stable functioning, even when assuming the (n−1) eventuality, so the unexpected disconnection of the more stabilizing load. This reconfiguration is an effective measure to constantly ensure a sufficient stability margin, even when low-bandwidth loads are offline. The capability of P-R algorithm is evaluated by a C-HIL test on a digital real-time platform. A Python code acts as a PMS in configuring the bandwidths on emulated converters via the Modbus communication protocol. The combination of a simplified stability assessment method with an optimization algorithm enables a fast bandwidth reconfiguration process without requiring excessive computational effort. These characteristics make the proposed approach suitable for integration into the shipboard Power Management System (PMS), providing central controllers with an online stability assessment and safe load management tool.