Real-time strategies to optimize the fueling of the fuel cell hybrid power source: A review of issues, challenges and a new approach

Besides a brief review of the issues and the challenges related to the real-time optimization (RTO) strategies for the Fuel Cell Hybrid Power Sources (FCHPS), a new RTO strategy is proposed and analyzed here to find the optimal values of both fueling flow rates for the FCHPS under a dynamic load cycle. The optimization strategy to search and track the optimal value is based on the Global Extremum Seeking (GES) algorithm. In comparison with the Static Feed-Forward (sFF) RTO strategy, where both fueling rates are controlled by the FC current, the GES-RTO strategy adjusts the FC current with values given by two GES control schemes. Thus, the fueling regulators are controlled by two reference currents which are a bit different to FC current. The performance obtained with the GES-RTO strategy proposed herein is shown in comparison with the sFF-RTO strategy for constant load, but also for dynamic load profile. In last case both strategies will use a Load-Following (LF) control for the boost converter that interfaces the FC system with the DC bus. The performance will be estimated considering the following indicators: the generated FC net power, the fuel consumption efficiency, the FC system efficiency, and the total fuel consumption during a load cycle. The fuel economy for 6 kW FC system during a nominal load cycle of 60 s could be up to 40 l if the GES-RTO strategy is used instead of the sFF-RTO strategy.