Matlab / simulink based-study on PEM fuel cell and battery hybrid system

This paper presents a dynamical control of fuel cell and battery hybrid system to supply a suddenly changing load. Because of the voltage drop when PEM fuel cell current increases, in this hybrid system, 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. 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: (a) when the fuel cell can afford the load, only fuel cell will power the load through DC/DC; (b) when the load goes exceeding fuel cell´s power range, the battery will help to power the load automatically; (c) when the load drops again, fuel cell can power the load alone and charge the battery if necessary.