Dynamic variable coupling analysis and modeling of proton exchange membrane fuel cells for water and thermal management

Dynamic variable coupling analysis is an important tool to properly design a control structure for complex multivariable and multi-physique systems, such as fuel cells. Fuel cell is an electrochemical energy conversion device which contains different inter-coupled dynamic phenomena in electrochemical, fluidic and thermal domains. Among those dynamic phenomena, the management of water and thermal dynamics play an important role to achieve the optimized fuel cell performance. In this paper, a control variable coupling analysis of fuel cell dynamic behaviors are presented and discussed based on a dynamic proton exchange membrane (PEM) fuel cell model, which considers in particular the transient behaviors of membrane water content and cell temperature. Through the analysis based on the relative gain array (RGA) method, the effects of nonlinear coupling among different fuel cell control variables are shown. The analysis results can be used to optimize the controller design for fuel cell system.