Research On Control Strategy Of High Power PEMFC Air System

With the energy crisis and environmental pollution problem,proton exchange membrane fuel cell(PEMFC)has become a hot spot in the research field due to its advantages of clean,efficient and renewable.However,many auxiliary systems are needed when the fuel cells work.The air supply system,as the most important auxiliary system,directly determines whether the oxygen is sufficient and appropriate to participate in the reaction.When the oxygen in the reaction is insufficient,the output voltage of the stack will be reduced,the proton exchange membrane will be overheated,and the life of the stack will be reduced.When the air flow rate is higher than the demand,the whole system efficiency is reduced as the compressor power consumption is higher and the output power of the stack is not improved obviously.Therefore,it is of great significance to study the air supply system to meet the air flow rate accurately and rapidly which maintain the stable and efficient operation of fuel cell system.First,the experimental platform of the fuel cell air supply system including the centrifugal air compressor is built based on the research results in the word and the air supply system of the Ballard HD6.The electric control and communication mode of the experimental platform is designed.The control program of the experimental platform is written.The experimental platform consists of centrifugal air compressor,cooling system,ac motor,motor driver and PLC controller,etc.,which can realize on-line monitoring and control of air compressor and experimental data analysis and storage.Then,the experiment on the influence of the combination of butterfly valve opening and anti-surge valve on the air parameters of air compressor outlet was carried out on the experimental platform.The effect of anti-surge valve has been proved by experiments is affected by factors such as the butterfly valve opening.Under the condition of the same butterfly valve opening,the distance from the air compressor is farther,the effect of anti-value is better.Finally,a traditional PID control is used to control that outlet flow rate of the air compressor,and the analysis of experimental data indicate that the traditional PID controller has a limitation in the application of flow control.In order to improve the control effect of PID controller,a fuzzy adaptive PID controller is designed in this paper.The control effect of the fuzzy PID controller and the PID controller is compared through the experiment,which proves that the fuzzy adaptive PID controller is more effective.