Control Structure of a Micro Combined Heat and Power Fuel-Cell System for Lifetime Maximisation

Abstract

The aim of this work is how to analyse controllability and design a suitable control structure for a commercial stationary micro combined heat and power system (\mchp) where the focus is to optimise the life time of the fuel cell, which is the central component in the system and the most critical with respect to durability. A three-layered control approach is proposed, building on the pre-existing low-level regulatory layer. A middle-level controller handles reversible degradation phenomena before they cause lasting damage, inducing temporary deviations from the steady state to recover from e.g. catalyst contamination or electrode flooding. A high-level optimising controller sets the nominal operating conditions to maximise a specific objective function, based on prognostics and health management, in which the lifetime of the stack is of pivotal importance.