Modified Variable DC Approach Applicable to Fuel Cells and DOL Batteries in Shipboard Power Systems

Previously, a Variable DC approach has been proposed for hybrid fuel cell and battery shipboard systems. The approach was shown to reduce system powertrain losses, and hence cost of operation. However, in addition to cost, some vessel types are quite sensible to system weight and footprint. For such vessels, use of batteries without power converters is an attractive solution. However, the Variable DC approach is not applicable to batteries integrated without power converters. This paper proposes modifications on the previously presented Variable DC approach. The new approach enables reductions in system weight and footprint, while also achieving improvements in powertrain efficiency. The validation of the proposed method is carried out using a real-time hardware in loop test setup.