Real-time optimization strategies of Fuel Cell Hybrid Power Systems based on Load-following control: A new strategy, and a comparative study of topologies and fuel economy obtained

Abstract

An evaluation of currently optimization energy management strategies is done in this study. The load-following – based strategy for Proton Exchange Membrane Fuel Cell (FC) Hybrid Power Systems ensure the DC power flow balance using the FC system as main energy source. Thus, the battery will operate in charge-sustaining mode. So, the battery state-of-charge will vary in imposed window without need of monitoring the battery. Furthermore, the size and maintenance of the battery stack will decrease compared with rule-based strategies. So for the first time, the classification and evaluation of seven FC Hybrid Power Systems and their possible energy management strategies (including a new one) are performed using the performance indicators related to fuel economy and FC electrical efficiency of the FC system. Consequently, the optimization of the FC Hybrid Power Systems under variable load will mix these performance indicators through the weighting coefficients knet and kfuel into a new optimization function. A new switching strategy for the load-following control and real-time optimization loops is proposed to further increase the fuel economy based on the results obtained in this study. The objective of this study is to highlight how optimization function and switching strategy through choosing the weighting coefficients and the control references could improve the fuel economy. Thus, the design of the switching strategy based on available information about the current load demand and the distance to fuel stations is presented in this paper as well. This switching strategy will push hydrogen to become an energy carrier feasible for FC vehicles.