Study On The Water-Cooled PEMFC Thermal Managenment System Modeling And Control

Due to the necessity of social development for the energy supply and environmental protection, fuel cells, as satisfy the both requirements of green energy appear on the world stage. With advantages of low operating temperature, quick start, low noise, the Proton Exchange Membrane Fuel Cell is potential. But the nature of the PEMFC power generation is electrochemical reaction, therefore the output performance and life are affected by multiple operation parameters, such as temperature, gas flow, gas humidity, pressure, etc.Among them, temperature has influence on the catalyst activity and mass transport, which not only can improve the efficiency of the power, but also help maintain a healthy state of fuel cell. On the other hand, temperature mismanagement may cause performance degradation, PEMFC failure, even safety accidents. So the water-cooled thermal management of PEMFC has great significance for promoting the development of fuel cell commercialization.This paper summarizes the current research status of PEMFC from the points of temperature characteristic, thermal management model, control strategies and methods.Then the PEMFC is introduced from three aspects of principle, structure and application.Based on the polarization properties, the voltage model is established. After validating the reliability of the model with experimental data, the effect of temperature has been analyzed. According to the internal energy conservation, the water-cooling thermal management of PEMFC system model is set up. Under the premise of its temperature and water flow are consistent with the experiment, how thermal management control variables affect on temperature, output power and thermal management parasitic power.Secondly, on the basis of control requirement of thermal management, in order to solve the deficiency of constant temperature difference, constant pressure difference between gas and water to control water flow, the relationship of pressure difference and temperature difference under different current has been analyzed. The variable air and water pressure difference control strategy is proposed. It meets the constraints of temperature and pressure,retains the advantages of control decoupling and fast response as well, further optimizes control effect. Meanwhile, considering the net power generation efficiency, the control strategy of reducing parasitic power is put forward to improve its economy of PEMFC system.Finally, on the basis of the characteristics of thermal management control objects, the control effects of fuzzy, fuzzy PID and PID control effect are compared.