Research On The Temperature Control Of The Proton Exchange Membrane Fuel Cell

Proton exchange membrane fuel cell(PEMFC)has attracted more and more attention in academic and industrial circles.It is possible for PEMFC to replace the internal combustion engine in the future.The working temperature is a key parameter of the PEMFC system,because it has a great influence on the durability,economy and environmental adaptability.Therefore,it is both theoretically and practically important to study the temperature control of fuel cell system.In this paper,the research on the temperature control of the fuel cell is carried out,the key problems of temperature control in different stages are analyzed,and the solutions are put forward.First,the main reason of the temperature fluctuation during normal work condition is explained,and a model-based controller design method is established.The first step is to establish the system model.The second step is to establish the state space description of the system,and use Pade approximation to calculate the time delay.The third step is to design the control algorithm according to the characteristics of the system.The fourth step is to estimate the amount of state that can not be measured directly by using Kalman filter.Finally,the temperature fluctuation is controlled in a small range.The method has been applied to the vehicle system and the experimental bench,and also can be applied to other similar cooling systems.Then,the heating process of the fuel cell system in normal temperature is analyzed.This paper presents an optimization method for the global efficiency of the temperature rising process based on the energy type fuel cell power system.On this basis,using the rule based analysis to approximate the optimal solution,a real-time control strategy can be obtained,which can save 4.71 MJ energy when the heating time is 1000 seconds.In addition,a fast warm-up strategy is studied for the special case where the initial SOC of the power battery is very low.The exhaust gas recirculation can save up to 40% of the heating time.Finally,the low temperature experimental environment is built,and the start-up process of the fuel cell under the condition of zero degree is studied.Based on the experimental results,the physical model of the start-up process is established and validated.And the mechanism of the instability during the start-up process is provided by the model.The corresponding control algorithm is designed to achieve the optimal effect.