PEM fuel cell and battery hybrid system studied in Matlab/Simulink

This paper presents a dynamical control of fuel cell and battery hybrid system to supply a frequently changing load. In this paper, a hybrid system is built in order to solve a big problem that the voltage will drop when PEM fuel cell current increases: the fuel cell is used to supply the rated power to the load, a Lithium battery will supply peak power that the load demands, meanwhile, the fuel cell will charge the battery when the battery voltage is low during the light load condition. A DC/DC converter is to maintain the overall voltage to constant and serve the load properly. In this system, the main control theory is as follows: (1) when the fuel cell can afford the load, only fuel cell will power the load through DC/DC, and charge the battery if necessary; (2) when the load goes exceeding fuel cell´s power range, the battery will help to power the load automatically.