Design Of New Energy Vehicle Hydrogen Fuel Cell Internal Resistance Online Monitoring System

For new energy vehicles with hydrogen fuel as power source,the safety and stability of hydrogen fuel cell stack as power generation system is one of the key factors for the healthy and stable operation of the vehicle.Real-time online monitoring and control of hydrogen fuel cell is an important step to ensure the safety and reliability of hydrogen fuel cell and timely troubleshooting.The hydrogen fuel cell management system manages all the dynamics of the cell as the nerve center,so an online monitoring system based on a single fuel cell is designed in this system.The operating parameters that can directly reflect the current health status of hydrogen fuel cell include internal resistance,internal operating temperature and internal water content.Small changes in temperature and humidity in the reactor will cause fluctuations in electrochemical reaction efficiency,which will be reflected in the internal resistance value.In this system,a set of internal resistance signal acquisition module,temperature sensor module,humidity sensor module are designed to detect the internal resistance of single chip hydrogen fuel cell,and online data collection of reactor temperature and reactor water content is carried out.In this design,the SPWM signal at the front end drives the inverter circuit to generate the high-frequency sinusoidal excitation small signal which is used to inject minimal disturbance into the hydrogen fuel cell system,and then calculates the AC voltage and ac current collected at both ends of the battery,so as to obtain the internal resistance of a single cell.The internal temperature and water content of hydrogen fuel cell reactor are detected by the temperature and humidity sensor integrated in the whole reactor air outlet to collect the temperature and humidity of the exhaust gas indirectly.These simulation parameters can not only display the real-time status data on the spot,but also send the data to the One NET cloud platform of the supreme computer through the wireless module after the analog-to-digital conversion and operation of the STM32 core controller.The system also carries out the platform visual interface display,which can reflect the real-time refresh data,line chart comparison trend relationship,etc.,on the web and mobile terminals.Historical query data can also be saved on the cloud platform,facilitating users’ timely observation and monitoring.The fault diagnosis control part of the system sets the threshold of temperature and water content,and can manually or automatically open the corresponding control relay,cooling or drainage.In case of emergency,users will be alerted by sending a mailbox via cloud platform trigger.After making and testing,the system can accurately monitor the battery internal resistance,reactor temperature and reactor water content.The internal resistance test accuracy is 0.01mΩ,the temperature error range is ±0.5℃,and the humidity error is not more than1%RH.The communication is good,the data display is correct,and the operation state is stable.For engineering applications,it has the advantages of small size and easy to be integrated into the vehicle power stack system.It can provide a new scheme for online monitoring of hydrogen fuel cell status,and has a certain engineering value.