PULSE-WIDTH MODULATION OF HYDROGEN DELIVERY FOR PEM FUEL CELLS

Pulse-width modulation of hydrogen delivery is proposed to accomplish better performance of PEM fuel cells. By evaluating power consumption patterns and time delays associated with hydrogen and air consumption, optimal functional feedback controllers are developed. By matching the ON and OFF times for the hydrogen and oxygen supply valves, in conjunction with a system fuzzy controller (1), the power output is matched to specific load requirements. The fluid transient behavior is also monitored, to develop functional relationships between the power curve, and the fluid conditions, in order to optimize the system performance. These functions are then used to update and improve the performance of the controller.