Parameter identification strategy for fractional-order hammerstein MIMO systems with PEMFC experimental validation

Abstract

This study introduces a four-stage method for parameter identification in non-homogeneous fractional-order Hammerstein MIMO systems, which solves the problems of difficulty in determining the initial values of parameters and high computational complexity. The method gradually shifts from homogeneous models to non-homogeneous models, which enhances the convergence stability of the algorithm and reduces the computational complexity. Initially, the system is simplified to a single homogeneous model, then each output subsystem is treated as homogeneous. Non-homogeneous characteristics are introduced in the third stage, and by the fourth, the entire system is considered non-homogeneous. This gradual refinement avoids the complexity of determining the initial values of the fractional order. The improved Levenberg-Marquardt algorithm, combined with the multi-innovation principle, enhances identification accuracy and global search performance. A numerical example and a PEMFC experiment verify the effectiveness and the superiority of the method.