Apparatus and method for softsensing fuel cell system

An apparatus for soft-sensing a fuel cell system, comprising:

• a connecting unit detachable from a control unit for being connected to an outside of a stationary fuel cell system;
• a collecting unit connected to the connecting unit and receiving data of the stationary fuel cell system, the data including at least a process variable;
• a quality variable predicting unit connected to the collecting unit and predicting a quality variable of the stationary fuel cell system based on an experimental model representing a correlation between the process variable and the quality variable previously measured depending on a changed value of the process variable;
• and
• a monitoring unit connected to the quality variable predicting unit and outputting the predicted quality variable,
• wherein the quality variable predicting unit is configured to predict the quality variable predictable including at least any one of a concentration of carbon monoxide in a reformed gas at a rear end of a fuel converting system, and a concentration of methane in the reformed gas at the rear end of the fuel converting system.