Voltage Control of Parallel-Connected Dual-Active Bridge Converters for Shipboard Applications

Power-electronics-based medium-voltage direct current (MVDC) shipboard power systems consist of several interconnected feedback-controlled switching converters. Such systems suffer from stability degradation owing to the negative incremental resistance of the constant-power loads. To tackle the stability problem, system-level stabilizing control methods were proposed acting on either the load-side or source-side converters. In this paper, the three-phase dual-active bridge (DAB3) dc-dc converter is considered to realize the MVDC bus. A master-slave control approach is introduced which not only ensures system-level stability but also optimizes the load-sharing among the DAB3 converters. A nonlinear control technique for the master controller is compared with the proportional-integral controller with linearized feed-forward compensation. The comparison is performed through the simulations in MATLAB/PLECS.