Design And Experimental Research On Test And Control System Of Open-cathode And Self-humidifying PEMFC

With the high efficiency and environment-friendly advantage,fuel cell has become an important part of the new energy resources.Among this,Proton Exchange Membrane Fuel Cell,PEMFC,has broad application prospects in many fields because of its distinct advantages of specific power,high energy conversion efficiency,fast start and environmental protection.The open-cathode and self-humidifying PEMFC adopts the combination of air cooling and self-humidification technology,which greatly simplifies the auxiliary machine system.However,the simplification will also cause multiple factors to be coupled together.In order to better understand its performance and speed up the commercialization process,therefore requires a fully functional test and control system.First of all,this paper designs a set of multifunctional open-cathode and self-humidifying PEMFC test and control system based on MCC/NI data acquisition card and LabVIEW monitoring software platform.The hardware part mainly introduces the signal sampling and conditioning circuit,the power drive circuit,and the analog voltage to PWM conversion circuit,The software part mainly introduces the control flow of the system.The test and control system can adjust the relevant operating parameters online according to the actual operating state of the PEMFC stack,taking into account the startup and shutdown control of the PEMFC stack,the control of the anode exhaust gas,the compatibility of different fan speed regulation modes,temperature control,etc.,In addition,it also can save and real-time display of the PEMFC stack related state parameter,friendly man-machine interface,has the very high practical value,and lays a foundation for the experimental research and application of open-cathode PEMFC.Secondly,the paper analyzes the mechanism of the performance attenuation of PEMFC in the startup and shutdown condition,namely the existence of hydrogen-air interface.Hydrogen-air interface will lead to the cathode side of high voltage,and the corrosion of carbon catalyst carriers,in order to reduce the high single cell voltage value and the duration of the high voltage in startup process,with homemade PEMFC stack which own nine single cell as the research object,using the test and control system,compared the various startup strategy,it is concluded that the optimal startup strategy: reduce the hydrogen inlet pressure and put a 2.3? load in when the average single cell voltage value of the stack is greater than 0.38 V,this strategy utmost reduce the high single cell voltage value and the duration of the high voltage,and is freed from the single cell voltage monitoring,so it is a very effective startup strategy whic prolonging durability of the stack.Finally,the 40 single-cell open-cathode PEMFC stack was used as the research object,and the optimal operating temperature value of the multiple PEMFC stack current was tested,and the formula for calculating the optimal operating temperature and the output current of the cell stack was fitted.The PID control algorithm was written on the measurement and control system.Through the load increase and load decrease experiment,the effectiveness of the PID control to achieve the optimal temperature control of the PEMFC was verified.After,adjusting the fan control signal to the minimum value of 0V for a period of time and then adjusting the control signal to the maximum value of 10 V,it was found that short-term oxygen starvation is a method that can significantly increase the short-time output performance of the PEMFC stack under load conditions,and The reason why the method can improve the short-time output performance of the PEMFC stack is brief analyzed.