Fuel cells are an attractive option for alternative power and of use in a variety of applications. This paper proposes a state space model for the solid oxide fuel cell (SOFC) based power system that comprises fuel cell, DC-DC buck converter, and load. In this investigation we have taken up a case study for SOFC feeding a DC load where a DC-DC buck converter acts as the interface between the load and the source. A proportional-integral (PI) controller is used in conjunction with pulse width modulation (PWM) that computes the pulse width and switches the MOSFET at the right instant so that the desired voltage is obtained. The proposed model is validated through extensive simulation using MATLAB/SIMULINK. Controller for the fuel cell power system (FCPS) is prototyped using XC3S500E development board containing a SPARTAN 3E Xilinx FPGA that simplifies the entire control circuit besides providing additional flexibility for further improvement. The results clearly indicate improved performance and validate our proposed model.

Fuel cell systems are enhancing due to interest to supply electricity in remote areas as well as distributed power generation especially during the peak loads. Fuel cell generation becomes popular due to cleanliness, portability and suitability for electricity and heat generation. This paper presents the modeling of a fuel cell power plant (FCPP) in terms of fuel cell, dc-dc converter, dc-ac inverter and power system parameters, to interface with loads or grid. The control strategy of this model is hysteresis current controller (HCC). HCC is used to generate inverter switch pulse for the ac grid voltage. MATLAB/SIMULINK is used to validate the modeling and simulation of fuel cell generation and power conditioning unit. The proposed control strategy makes the distribution generation system work properly when the voltage disturbance occurs in the distribution system.