| Hydrogen energy is a clean and renewable energy source and a hot topic in global research.As an ideal source of electrical energy in the future,the fuel cell has a high utilization rate of hydrogen energy and is a high-efficiency energy conversion device.Compared with many fuel cells,Proton Exchange Membrane Fuel Cell(PEMFC)has many outstanding advantages,such as rapid startup at room temperature,long life,no electrolyte loss,etc.This paper mainly studies and analyzes the fuel cell thermal management control strategy,optimizes the gas channel structure and the dynamic performance under different working conditions,so as to improve the performance,life and reliability of the fuel cell.The main research work and conclusions are as follows:This paper first describes the research background and significance of proton exchange membrane fuel cell,and analyzes the dynamic characteristics,thermal management system control strategies and gas flow channel structure optimization of the fuel cell research status.Then a dynamic model of proton exchange membrane fuel cell stack was established,this model includes the output voltage model of the fuel cell stack,the cathode flow channel model,the anode flow channel model and the water transfer model in the membrane.Auxiliary system model has been established,the model includes air supply pipe model,air cooler model,humidifier model and thermal management system model,etc.A three-dimensional dynamic model of PEMFC is established,which involves describing the continuity equation,conservation of momentum,conservation of energy,electrochemistry,and Maxwell-Stafen differential control equation.Then,this paper proposes two thermal management control strategies: flow following current and power mode and neural network auto disturbance rejection method,and establishes the PEMFC thermal management system control model.Different thermal management control strategies are adopted to optimize the thermal management system,so as to ensure that the temperature of the fuel cell stack is at the optimal value,and improve the performance and reliability of the fuel cell stack.Under variable load conditions,research and analyze the effects of different thermal management control strategies on fuel cell performance and temperature.The research results show that the control effect of the flow following current and power control strategy is better,followed by the neural network auto disturbance rejection strategy.Finally,a three-dimensional single-phase straight channel non-isothermal proton exchange membrane fuel cell basic model was established.When solving the steady state,COMSOL Multiphysics with MATLAB is used,and the multi-objective genetic algorithm(NSGA-III)is used to optimize the calculation of the PEMFC channel cross-section and other parameters.This paper proposes a novel bullet wave-like flow channel,the influence of different flow channel structure parameters on the performance of the fuel cell is compared,and the best flow channel structure is selected as a new basic model to optimize the fuel cell structure parameters,thereby improving the performance of the fuel cell.A three-dimensional model of a parallel serpentine flow channel fuel cell was established,and a multi-objective genetic algorithm was used to optimize the calculation of the fuel cell flow channel cross section.Under start-stop and variable load conditions,the dynamic performance of proton exchange membrane fuel cell was studied.The research results show that the trapezoidal gas channel cross-section is more conducive to improving the performance of the fuel cell.The bullet wave-like channel can improve the performance of the fuel cell.For bullet wave-like channel fuel cell,the flow channel cross-section shape and wave-like position have a greater impact on the performance of the fuel cell.When the operating voltage changes step by step,the current density,maximum temperature of the fuel cell,and the average molar concentration of the reaction gas all have overshoot and undershoot. |
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