【作者】 李靖；

【导师】 汤浩；

【作者基本信息】 电子科技大学 ， 控制科学与工程， 2024， 硕士

【摘要】 氢质子交换膜燃料电池具有工作温度低、零排放和高能效等优点,在交通领域具有广阔的应用前景,但电堆性能和氢的高效利用仍是阻碍该技术发展的重要屏障。质子交换膜燃料电池阳极再循环提高了氢气的利用率,但导致了氮气积累,引起电堆性能降低,需要定时打开排气阀进行阳极排放,排放过程恢复电堆性能的同时会引起部分氢气浪费,降低氢气利用率。针对车用燃料电池供氢系统进行排气策略优化不仅可以提高电堆性能,还能降低系统氢耗、提高运行的经济型。本文以车用燃料电池供氢系统为研究对象,基于氢气循环泵与引射器并联的优化供氢结构,针对部件特性测试、系统建模分析、排气策略优化等方面展开了如下研究工作:(1)基于实验开展供氢系统氢循环关键部件特性研究。首先,搭建氢气循环泵和引射器实验平台,设计并开展氢循环关键部件特性实验,研究不同操作条件对氢气循环泵流量特性和功耗特性的影响,研究引射器端口流量和引射比随不同操作条件的变化情况。然后,获取部件特性实验数据,分析氢循环关键部件性能特性,综合评价部件性能,为系统建模提供实验依据与数据支撑。(2)针对供氢系统核心部件及其参数耦合关系进行分析,建立供氢系统集总参数模型。基于电堆机理特性及经验公式建立电堆模型,基于热力学和流体力学原理建立供应管道及阀门模型,采用机理与数据相结合的方法建立引射器模型,采用前馈神经网络方法,建立氢气循环泵模型。在Simulink环境中建立供氢系统集总参数模型,并根据实验进行模型验证,电堆电压模型平均误差为0.55%,氢气循环泵决定系数R~2为0.99841,引射比拟合R值为0.9891,模型拟合度好,平均误差低。(3)基于供氢系统集总参数模型,提出一种基于混合策略改进麻雀搜索算法的燃料电池供氢系统排放优化策略。首先,综合考虑电堆输出、氢气循环泵消耗、氢气排放损失的影响,提出阳极综合能量效率这一供氢系统排放过程评价指标,基于该指标分析排气间隔和排气时长对供氢系统的影响;然后,设计了应用于供氢系统排放过程最优综合效率问题的麻雀搜索算法、单策略改进和混合策略改进麻雀搜索算法三种算法,经过性能对比分析,结果表明混合策略改进麻雀搜索算法在跳出局部最优解方面有明显的优势;最后,综合对比典型供氢结构的无排气优化方案、优化供氢结构的无排气优化的方案、优化供氢结构的排气优化方案三种方案的仿真结果,进一步验证结构和排气策略优化对供氢系统排放过程优化的重要意义。更多还原

【Abstract】 Hydrogen proton exchange membrane fuel cells have advantages of low operating temperature,zero emission and high energy efficiency,and hold immense potential for applications in transportation,but the performance of the fuel cell stack and the efficient use of hydrogen are still important barriers to the development of this technology.The anode recirculation of proton exchange membrane fuel cell improves the utilization rate of hydrogen,but leads to the accumulation of nitrogen,which causes the degradation of the performance of the stack,and it is necessary to open the purge valve at regular intervals,and the purge process recovers the performance of the stack while causing part of the hydrogen to be wasted,which reduces the utilization rate of hydrogen.Optimizing the purge strategy for the hydrogen supply system of automotive fuel cells can yield several benefits.It not only improves its performance of the stack but also reduces hydrogen consumption,and improves operational efficiency.In this research,the focus is on the hydrogen supply system for automotive fuel cells.Based on an optimized hydrogen supply structure that incorporates the parallel connection of a hydrogen circulating pump and ejector,comprehensive investigations have been conducted encompassing component characteristic testing,system modeling analysis,and purge strategy optimization.1.Characterization of critical components of the hydrogen supply system’s hydrogen cycle is carried out based on experiments.Firstly,the experimental platforms of the hydrogen circulation pump and ejector are set up to design and carry out the characterization experiments of key components of the hydrogen cycle to study the effects of different operating conditions on the flow rate and power consumption characteristics of hydrogen circulation pump,and to study the changes of ejector port flow rate and ejection ratio with different operating conditions.Then,the experimental data of component characteristics are obtained to analyze the performance characteristics of key components of the hydrogen cycle,comprehensively evaluate the performance of components,and provide experimental basis and data support for system modeling.2.The core components of the hydrogen supply system and their parameter coupling relationships are analyzed,and the aggregate parameter model of the hydrogen supply system is established.Based on the stack’s mechanical characteristics and empirical formulas,a stack model is developed;based on the principles of thermodynamics and hydrodynamics,a model of the supply pipeline and valves is built;a model of the ejector is established by combining mechanism and data;and a model of the hydrogen circulation pump is created by using the feed-forward neural network method.A model of the aggregate parameters of the hydrogen supply system is established in the Simulink environment,and model validation is carried out based on experiments;the average error of the stack voltage model was 0.55%,the coefficient of determination of the hydrogen circulating pump R~2 was 0.99841,and the corrleation coefficient of the ejector’s circulation ratio R was 0.9891,the model fit was good and the average error was low.3.Based on the aggregate parameter model of the hydrogen supply system,a purge optimization strategy for the hydrogen supply system of fuel cells based on the mixed-strategy improved sparrow search algorithm is proposed.Firstly,the integrated energy efficiency of anode is proposed as an evaluation index for the purge process of the hydrogen supply system by considering the effects of the stack output,the energy consumption of the hydrogen circulation pump,and the loss of hydrogen purge,and the effects of the purge interval and purge duration on the hydrogen supply system are analyzed;then,three kinds of sparrow search algorithms,a conventional,a single-strategy improved algorithm,and a mixed-strategy improved sparrow search algorithm,which are applied in the problem of optimal integrated efficiency of the purge process of the hydrogen supply system,are designed and analyzed in comparison.Then,three algorithms,namely the sparrow search algorithm,single-strategy improved,and mixed-strategy improved sparrow search algorithms,are designed to optimize the integrated efficiency of the hydrogen supply system purge process.The results show that the mixed-strategy improved sparrow search algorithm demonstrates an obvious advantage in jumping out of the local optimal solution.Finally,the purge performance simulation results with three hydrogen supply system structures,namely the conventional non-vented,optimized non-vented,and optimized vented,are compared.The analytical results prove that optimizing the hydrogen supply system structure and its purge strategy is vital to improving the hydrogen purge process.更多还原