Fault analysis for humidity management is presented in [24]. During random variations in load requirements in real time scenarios, the demand of reactants increases ordecreases. If this demand for the reactants does not meet the actual requirements, then there is a danger of fuel or oxygen starvation or excess can damage the cell stack consequently reducing the life span of the system. Control design is proposed to maintain the desired value of oxygen excess ratio of 2 in order to ensure smooth power delivery andto maintain a constant stack voltage for the desired circumstances. Detailed block diagram of PEMFC is shown in Figure 2. Oxygen excess ratio of the fuel cell stack must be kept constant because if it fluctuates above or below the reference value, it degrades the overall system performance and can cause damage to the stack.