| Magnetic refrigeration technology is a kind of energy-saving,green and efficient refrigeration technology.Today,although magnetic refrigeration technology is not widely used in the field of life,but through recent studies,the technology is expected to be commercialized,so as to replace the traditional refrigeration into thousands of households.The development and application of magnetic refrigeration technology is a system engineering,among which,increasing the heat exchange efficiency inside the refrigerator is an ideal means to realize its commercialization.After years of accumulation,Baotou Rare Earth Research Institute has developed reciprocating and rotary magnetic refrigeration refrigerators.Its controller uses PLC as the main control core and the control method is open-loop control.However,PLC is relatively expensive,in order to reduce the cost and miniaturize the magnetic refrigeration refrigerator controller,this thesis uses STM32 microcontroller as the main control core to develop the magnetic refrigeration refrigerator controller.Due to the difficulty of materials to further improve the refrigeration effect,this paper tries to improve the refrigeration effect from the control point of view,and carries on the simulation calculation and control algorithm optimization research respectively by using reciprocating and rotating magnetic refrigeration equipment.(1)By using the method of simulation calculation,the theoretical models of the internal heat exchange in the refrigeration bed of two magnetic refrigeration refrigerators based on the PRINCIPLE of AMR cycle are established,and the influence of their important parameters on the cooling capacity of the models is discussed respectively.The results show that when the parameters are in the normal range,the refrigeration capacity of the reciprocating magnetic refrigerator is directly proportional to its circulation frequency and heat transfer fluid velocity,and inversely proportional to the porosity of the magnetic working medium.The refrigeration capacity of rotary magnetic refrigerator is proportional to the rotating speed of working medium and the speed of heat transfer fluid.(2)Through numerical simulation analysis and considering the actual adjustable factors in the field,the heat transfer fluid velocity of reciprocating refrigerator and the rotating speed of rotating refrigerator working medium were selected to optimize the refrigeration efficiency.In view of the inertia and hysteresis characteristics of temperature system,fuzzy technology and PID algorithm are combined,fuzzy rules are formulated and PID parameters are adjusted online by integrating expert experience.The simulation results show that the fuzzy PID algorithm can improve the refrigeration effect of the two magnetic refrigeration refrigerators.The refrigeration temperature span of reciprocating magnetic refrigeration refrigerator increases by about 10 K,and that of rotary magnetic refrigeration refrigerator increases by about 6K.(3)Complete the hardware and software design of the new controller of reciprocating magnetic refrigerator with STM32 series SCM as the main control core.Hardware is mainly for the main control core,signal acquisition,display,voice broadcast module circuit design,software is mainly to achieve the function and fuzzy PID control algorithm,and finally to complete the physical production of the controller. |
