Fast Model Predictive Control of PEM Fuel Cell System Using the L1 Norm

This work describes the development of a fast Model Predictive Control (MPC) algorithm for a Proton Exchange Membrane (PEM) fuel cell. The MPC cost-function used considers the sum of absolute values of predicted control errors (the L-1 norm). Unlike previous approaches to nonlinear MPC-L-1, in which quite complicated neural approximators have been used, two analytical approximators of the absolute value function are utilised. An advanced trajectory linearisation is performed on-line. As a result, an easy-to-solve quadratic optimisation task is derived. All implementation details of the discussed algorithm are detailed for two considered approximators. Furthermore, the algorithm is thoroughly compared with the classical MPC-L-2 method in which the sum of squared predicted control errors is minimised. A multi-criteria control quality assessment is performed as the MPC-L-1 and MPC-L-2 algorithms are compared using four control quality indicators. It is shown that the presented MPC-L-1 scheme gives better results for the PEM.