Power Flow Control through Differential Power Processing to improve reliability in hybrid systems based on PEM-Fuel Cell

This paper presents a decentralized control technique, implemented through a differential power processing topology, in hybrid PEM Fuel Cell systems. This strategy allows the control of the power flow in the cells. The purpose is to improve the maximum power point tracking (MPPT) of the different submodules and thus increase the efficiency of the system. In a PEM Fuel Cell device, several cells are connected in series, where the same current passes through all of them. This implies that the degradation of some membrane not only affects the partial performance but also the efficiency of the entire system. To solve the problem of a single fuel cell block, a serial sub-modules application has been considered. Now, this solution needs optimization techniques. Differential Power Processing (DPP) techniques have been implemented in the sub-modules to provide an effective solution to mitigate the mismatch impact on the energy obtained. The DPP architecture consists of a small micro-converter at the submodular level applied to the cell. The main objective is to apply an algorithm oriented to polarize each fuel cell sub-module at its optimum point, which allows balancing between fuel cells, regardless of external parameters. The proposed strategy does not preclude the hybridization of fuel cells with a hybrid energy storage system (HESS) based on batteries or ultracapacitors. This ensures fast power transients in the load while the fuel cell is maintained at this optimum MPPT. The effectiveness of the strategy has been validated by the Matlab/Simulink software simulation. The results obtained, merit figures and conclusions are also presented in this paper.