Multi-port power converter for segmented PEM fuel cell in transport application

To fulfill the transport applications, either for traction or on-board auxiliaries systems, a power generator based on fuel cell needs significant power. For this purpose, long fuel cell stacks, either monoor multi-stack systems, are already implemented as technological solutions. Long stacks though may be affected by spatial discrepancies (fluidics, temperature) causing possible failures. The latter often occur on localized stack sections. A corrective action has to be taken to quickly restore the fuel cell's state of health. As an alternative to fluidic action, segmented electric action is explored in this paper. First, an "All or Nothing" solution achieved with electrical by-pass circuits is analyzed: it proved simple to implement but restrictive to exploit. Consequently, a "gradual" action is proposed by using the power electronics converter associated to the fuel cell. Hence, the present work investigates the approach consisting in individually driving the electric power delivered by each segment of a long polymer electrolyte membrane fuel cell stack. Each segment is controlled independently according to its state of health. To achieve this objective, the article provides an extended multi-criteria analysis of several power converter topologies. The converter topology has to be in agreement with transportation specifications: simple, compact, having a high efficiency and should be adapted to manage fuel cell degraded modes. Among several studied topologies, resonant isolated boost stands out as a candidate topology. The related multi-port architecture and algorithm structure are analyzed by numerical simulations, taking into account degraded modes and technology considerations.