Research Article Online Soft Sensor of Humidity in PEM Fuel Cell Based on Dynamic Partial Least Squares

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Online monitoring humidity in the proton exchange membrane (PEM) fuel cell is an important issue in maintaining proper membrane humidity.The cost and size of existing sensors formonitoring humidity are prohibitive for onlinemeasurements. Online prediction of humidity using readily available measured data would be beneficial to water management. In this paper, a novel soft sensor method based on dynamic partial least squares (DPLS) regression is proposed and applied to humidity prediction in PEM fuel cell. In order to obtain data of humidity and test the feasibility of the proposed DPLS-based soft sensor a hardware-in-the-loop (HIL) test system is constructed. The time lag of the DPLS-based soft sensor is selected as 30 by comparing the root-mean-square error in different time lag. The performance of the proposed DPLS-based soft sensor is demonstrated by experimental results. 1