Study On Regulation Of Control Variables For The Output Optimal Performance Of Water-cooling PEMFC Stack

Proton Exchange Membrane Fuel Cell(PEMFC)is characterized as specific power,zero pollution and high efficiency.It is recognized as the preferred energy source for portable equipment,electric vehicles and stationary power plants.The application prospect is very broad.However,in engineering applications,due to the seal of the PEMFC stacks structure,the internal operating conditions of temperature and humidity can not be accurately detected by conventional detection methods.There is a strong coupling between the operating conditions,and the operating conditions are also affected by different control variables,which makes it very difficult to control the PEMFC stack accurately.In this paper,the influence of operating conditions on the output performance of PEMFC stack under different output stages and the influence of control variables on the operating conditions were studied.The regulation principle of the control variables was summarized when the output performance was optimal.Firstly,the mechanism model between the total internal resistance and the operating condition of the PEMFC stack was established,and the equivalence principle of the minimum internal resistance and the optimal output performance was established,then simulated the internal resistance model.Based on the principle of "total internal resistance minimum",to find the optimal operating conditions for the output performance of the stack under different output stages,then fitted the formula between the optimal operating conditions and the current density.The effectiveness of the optimal operating condition model was verified by designing the stack experiment.Then,the mechanism model between operating conditions of PEMFC stack and control variables was established.The model was simulated by MATLAB / Simulink,and the effect of different control variables on the operating conditions was analyzed.Last the model parameters were optimized by designed related experiments.Finally,the correlation coefficient calculation formula was introduced to calculate the correlation coefficient between different operating conditions and the internal resistance of the stack.The effects of operating conditions on the output performance of the stack under different output stages and the influence degree of the control variables on the operating conditions were studied according to the correlation coefficient.The regulation principle of the control variable was summarized when the output performance is optimal.