Research On Temperature Measurement And Positioning System For High Temperature Solid Oxide Fuel Cell Stack

Solid Oxide Fuel Cell(SOFC)is a power generation device that directly converts chemical energy into electrical energy at medium and high temperatures.It has the advantages of safety and environmental protection,high energy conversion efficiency,strong fuel adaptability and no need for precious metal catalysts.The working temperature of SOFC system is usually above 600℃.Abnormal temperature will directly affect the output power of SOFC power generation system and cause a series of faults inside the stack.Therefore,it is necessary to obtain the temperature distribution inside SOFC stack in time and judge whether there is leakage fault inside the stack through temperature change to reduce unnecessary losses.Due to the complex temperature distribution inside the stack and small size of airway opening,it is difficult to use traditional temperature measurement methods to insert temperature sensors into stack airway.Therefore,a new type of temperature measurement method needs to be designed to obtain the temperature distribution inside SOFC stack.The main research contents are as follows:(1)Based on two-dimensional laser rangefinder,quartz fiber optic thermometer sensor and three-degree-of-freedom Cartesian coordinate manipulator,a new type of SOFC stack temperature positioning device was built by selecting various components.The laser rangefinder scans the cathode airway of simulated stack to obtain point cloud position data of cathode airway of simulated stack.After point cloud data processing,accurate positioning of cathode airway position in stack was finally achieved.Through experimental verification,this SOFC temperature positioning device can accurately extend quartz fiber optic probe into cathode airway of simulated stack providing technical assistance for obtaining temperature data in cathode airway of simulated SOFC stack and construction.(2)Based on position coordinate values in cathode airway of simulated stack multiple quartz fiber optic probes were extended into cathode airway in array using three-degree-of-freedom Cartesian coordinate manipulator to obtain temperature data in cathode airway.Kriging interpolation method(Kriging)and inverse distance weighted interpolation method(IDW)were used for interpolation to construct internal temperature field in simulated stack.Compared with actual measured temperature data it was found that Kriging interpolation method had better effect than inverse distance weighted interpolation method after construction.(3)Based on diagnostic methods using Ensemble Empirical Mode Decomposition(EEMD)and Hilbert Transform(HT),analysis was performed on obtained abnormal temperature and voltage signals from kilowatt-level experimental platform combining time-domain feature extraction fault information setting threshold value to judge whether leakage fault occurred in cell or not.Feasibility was verified through experimental data finding that temperature compared with voltage signal could reflect occurrence more quickly.