Strategy for controlling a fuel cell power requirement

Power demand controller that prevents a power request signal to a fuel cell stack controller more compressor air and hydrogen gas supplies, as it is necessary to meet the current performance requirements of the vehicle. The stack controller generates a signal of the available current from the fuel cell stack. This signal and the measured current which is actually drawn from the stack will be received by a proportional-integral (PI) controller in the power demand controller. If the available stack current is significantly greater than the stack current used, the PI controller provides an output signal that reduces the power request signal to the stack controller, so that the generated by the stack current and the current drawn from the stack current are substantially equal. A transition detector switches the PI controller during a power transfer upwards so that it does not reduce the power request signal.