H∞ state estimation of permanent magnet linear synchronous motors using a linear matrix inequality approach

This paper presents a novel state estimation method on permanent magnet linear synchronous motors (PMLSMs) through the H_∞ filtering viewpoint. The dynamic characteristic of the PMLSM is analyzed and the discrete state equation model for the PMLSM is developed. To give the velocity and position estimation of the linear motor, an H_∞ filtering problem which allows certain presence of uncertainties is constructed. The uncertainties include parameter variations, noises and unmodeled dynamics. Afterwards the H_∞ filtering problem is solved using a linear matrix inequality (LMI) approach. The simulation results show that the proposed method is able to predict the motor velocity and position with minimum error.