A new control strategy for a higher order proton exchange membrane fuel cell system

Abstract

In this paper, a new cascade control strategy is proposed for a higher order Proton Exchange Membrane (PEM) Fuel Cell system for improving the performance on the basis of stack voltage. In the proposed strategy, stack voltage is considered as the primary objective and maintaining oxygen excess ratio value as a secondary aim, by manipulating the air compressor voltage. A higher-order PEMFC model is reduced to lower order integer and fractional models using varied model reduction techniques, which are then used to realize the primary as well as secondary controllers. Both integer and fractional order PID controllers are designed for the reduced order models and then implemented for the higher order system. The control performance is evaluated for disturbance rejection, system model mismatch and better controlled output for continuous random disturbance on the basis of Integral Absolute Error and controller effort. The outcome of the proposed control strategy is advantageous in terms of disturbance rejection, robustness, parameter uncertainty and reduction of plant-model mismatch.