A Cross-Current Compensation Control Scheme to Improve Voltage Regulation and Power Sharing in DC Shipboard Microgrids

The ability to maintain the power balance, and effectively share the demand power among the available generating units is one of the essential requirements of a dc shipboard microgrid. When multiple power sources participate in the voltage regulation of a common dc-bus, droop control is typically used and a steady-state error in the voltage cannot be avoided. This work investigates a distributed control strategy inspired by the cross-current compensation technique, originally developed for ac power plants, that allows to eliminate the steady-state voltage error while enforcing the current sharing. The sources participating in the voltage regulation are equipped with a cascading controller where the outer voltage control loop, fed with the compensated voltage measurement, generates the reference signal for the inner current control loop. Control equations are developed, and a set of real-time simulations is performed. Results show that the proposed control strategy is effective in eliminating the steady-state voltage error and ensuring current sharing. Moreover, the control strategy exhibits a fail-safe behavior that allows the system to remain stable even in the event of compensation failure.