Model based control strategies to control voltage of Proton Exchange Membrane Fuel Cell

The present work deals with the evaluation of model based control strategies for a PEM fuel cell to control voltage. PEM fuel cell is an electrochemical device that converts the chemical energy to electrical energy. Stack voltage is affected by many factors like stack temperature, moisture content of the membrane, partial pressure of hydrogen and air, inlet rate of hydrogen and air and also fuel starvation affects the rate of reaction and hence the voltage produced. In this work, two single input single output models are taken with stack voltage as controlled variable and hydrogen and air flow rate as manipulated variables respectively. The simulation study on two different control structures i.e., feedback and feedback plus feed forward control structures evaluates the effectiveness of proposed controllers concerning set-point tracking and disturbance rejection. Comparative study is carried out by simulations by implementing various model based control strategies, PI, IMC-PID and MPC. The results shows that MPC gives best results in terms of Integral Square error (ISE), Integral Absolute error (IAE) and controller effort (TV). In addition, robust stability analysis is carried out for uncertainty in the process parameters. Also, the controller fragility is studied for uncertainty in the controller parameters.