| Due to resource depletion,as a renewable energy,biomass has great potential for development and value.Temperature control is essential for combustion efficiency and thermogravimetric analysis equipment is an important material research equipment.The relation between the mass and temperature of the sample is measured at the program-controlled temperature,and the characteristics of the biomass combustion are analyzed,which are provided for the efficient use of energy.The thermogravimetric analysis equipment used for material research and development is smaller in size,but has more function,more strict temperature control requirements.In this paper,the complex operating condition of thermogravimetric analysis system was studied in detail,an improved temperature control algorithm was proposed for the temperature nonlinearity and interference,and the structural design and development of thermogravimetric analysis system were completed.Firstly,the method of temperature control has used in thermogravimetric analysis equipment was studied in this paper.The characteristic of thermogravimetric system temperature was analyzed through the studying and summarizing a large number of literatures.Using the Fourier heat conduction law,convective heat transfer law and thermal radiation law,the temperature field model of thermogravimetric analysis system was established.The temperature distribution under a variety of heating conditions and the main factors affecting the temperature control was analyzed by ANSYS software.Building on the study of traditional temperature control method,an improved temperature control algorithm based on Fuzzy-PID algorithm was constructed.Simulation results show that the improved control algorithm has the characteristics of fast response and high accuracy,and achieves the ideal control effect.Secondly,the thermogravimetric analysis system was designed and developed based on STM32 in this paper.The system mainly includes the following parts:box-type resistance furnace;gas module for achieving combustion gas transmission;signal collect module consisting of K-type armored thermocouple,signal processing module and high precision digital balance,aiming at collecting the quality and temperature data of combustion;the control and operation module consisting of STM32 controller,SCR power regulator AP1-40,to control the function of each module and to realize temperature control on the basis of improved Fuzzy-PID control algorithm;PC LabVIEW human-machine interface,through the RS232 serial port,communication with the controller to receive data from the inferior machine in order to display and store the measurement data and other functions.Through a large number of experimental analysis and verification in this paper,the effect of fuzzy optimization algorithm based on Fuzzy-PID was better than the conventional PID control,which has better control quality in steady-state error,adjustment time and overshoot.The practical application also shows that the thermogravimetric analysis system designed in this paper is stable and functional,which can meet the experimental requirements of thermogravimetric analysis. |
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