On the energy efficiency of standalone fuel cell/renewable hybrid power sources Part II: Simulation results for variable load profile with different renewable energy sources profiles (RES)

In the first part of the paper two proposed topologies are compared for constant load profile without Renewable Energy Sources (RES) power. The performance for these Hybrid Power Source (HPS) topologies are compared based on the following indicators: fuel consumption efficiency (Fuel
_eff
), FC net power and total fuel consumption (Fuel
_T
). The second part of the paper presents the simulation results for variable load profile with different renewable energy sources profiles (RES). As well as in the first part of the paper, the Extremum Seeking Control (ESC) optimization of the Fuel Cell (FC) electrical energy efficiency and the total fuel consumption will be implemented here to find the global maximum of the multimodal optimization function defined here as the FC net power. The load dynamic profile for both topologies (Air-LF, Fuel-LF) is set using the following sequence of the load currents: time sequence [s]: [0 2 3 8 9 10 10.5 12] and the sequence of the load currents [A]: [14 14 29 29 -6.5 -6.5 29 29]. The RESs power profile it is obtained using photovoltaic panels and wind turbines, for a sunny day with clouds and moderate wind during the evening. The performance for these HPS topologies are compared for variable load profile with different renewable energy sources profiles (RES) based on the following indicators: fuel consumption efficiency (Fuel
_eff
), FC net power and total fuel consumption (Fuel
_T
). The power architecture is implemented and simulated in Matlab-Simulink ® environment.