Research on Dynamic Response of Hybrid Power Source Systems with PEMFCs and Lead-Acid Batteries

The fuel cells (FC) for vehicle and home power generation application is widely developed during recent years. Because the fuel cell does not have capability for energy storage and its output voltage is easily affected by load variations and polarization loss, the power electronic technique is required to solve the problems of the unstable output voltage and fast energy compensation. And to better design these kinds of applications, the FC dynamic model is required. Due to the PEM (polymer electrolyte membrane) FC stack characteristic, the stack temperature will affect the output voltage, output current and the stack temperature. Therefore, how to obtain a stable output and the optimum control is the focus of this paper. The current mode control is applied for the proposed system. A good dynamic response can be achieved when the load changes. A digital signal processor (DSP) is applied for the system control. Finally, a 600 W hybrid generation system including the fuel cells, lead-acid batteries and a bi-directional dc/dc converter is constructed and verified through experiments.