Study Of Dynamic Modeling And Control Strategy For Proton Exchange Membrane Fuel Cell Thermal Management System

As an important alternative energy,hydrogen energy has remarkable advantages such as diverse sources for hydrogen generation,high energy conversion efficiency for hydrogen application and low emission characteristic.As one of the most significant technologies for hydrogen utilization,proton exchange membrane fuel cell（PEMFC）is widely applied in transportation,power plant,portable power source and etc,due to its high energy efficiency,power density and system compactness.PEMFC generally operates under low temperature less than 100 ℃ and the temperature affected electrochemical reaction and water content distributions are critical to the fuel cell performance and lifetime.Moreover,the thermal behavior inside the PEMFC stack couple with the multi-physical processes including fluid dynamics,reaction and mass transfer.It remains a challenge to realize accurate and robust thermal management for the PEMFC system operation under various situations.In this thesis,a fuel cell model based on the thermodynamic and multi-physical mechanisms of the PEMFC system is developed to study the dynamic thermal behaviors.With validation of the model by PEMFC system tests,the model-based system control strategies for the thermal management are proposed and optimized for reliable and robust system operation.The major contents are as follows:1.The recent researches on fuel cell thermal management system design,dynamic model and control strategy are reviewed and introduced.With the self-designed PEMFC system,experiments under various thermal conditions are designed and conducted to investigate the temperature distributions of the fuel cell stack,the dynamic behavior of stack temperature and temperature response to varied operating conditions.2.With the validation of experimental tests,a comprehensive dynamic PEMFC system model is developed based on the fuel cell thermodynamic and multi-physical mechanisms.The influence of temperature on the fuel cell stack performance and system thermal behavior under different operating conditions is analyzed with the model simulations.3.Based on the developed thermodynamic model of PEMFC system,the stack operating temperature and the temperature deviation between the stack inlet and outlet are regulated independently with the proposed control strategy.The coupled PID control strategy optimized with particle swarm method is proved to be capable of precise dynamic control and the artificial neural network based method for controlling parameter prediction is proposed for the online application of dynamic controller.