Disturbance Observer Based Control for PEMFC Generation System

This paper proposed the disturbance observer based control for the PEMFC generation system. First we analysis the transient behaviour of a polymer electrolyte membrane fuel cell (PEMFC) system following abrupt changes in the stack current by using a non-linear dynamic, control-oriented computer model. Then the model is used to develop a PID control scheme to regulate the transient behaviour of the PEMFC system with respect to maintaining the necessary level of the oxygen partial pressure in the cathode following abrupt changes in the stack current demanded. Maintaining the level of oxygen in the cathode is one of the key factors in operation of a fuel cell stack. Following that we give the procedure of designing the nonlinear disturbance observer and compositing the nonlinear disturbance observer to the controller. The global exponential stability of the proposed disturbance observer is guaranteed by selecting design parameters, which depend on the maximum of the oxygen stoichiometric excess and operation conditions of PEMFC systems. The performance of the proposed observer is demonstrated by tracking the excess oxygen ratio while the disturbed current vary. The composite controller improves disturbance attenuation ability of the PEMFC system. Both experimental and simulation results show the disturbance observer works well. It can be applied in PEMFC generation system for various purposes such as temperature compensation, and fault diagnosis.