Multivariable control for air management system in fuel reforming Fuel Cell Vehicle

With the purpose of meeting the specifically restrictive requirements of fuel reforming Fuel Cell Vehicle, this paper brings into focus the issues of transient operation of Fuel Cell systems, and presents a multivariable control methodology for Fuel Cell Air Management System. Indeed, considering the highly non-linear and coupled behaviour of thermo-fluid equations, the penalizing sensors dynamics, and the uncertainty on model parameters, design and control of such a complex air system require robust control strategies, that will ensure multiple control objectives while remaining suitable for onboard integration. In a first step, a dynamic and non-linear model exhibiting the main dynamics of the considered air system - based on lumped parameter pneumatic models combined with semi-empirical actuators models - is briefly described. Then, a classical approach is followed to obtain a reduced model that balances model fidelity with model simplicity. In a second step, we deduce from our model-based design methodology a LQ control structure - based on a multivariable state feedback - that limits the deterioration of performances by compensating inherent couplings and sensors dynamics. The validity of this approach is compared to monovariable strategies in simulation environment, and checked on a dedicated air supply system test bench.