Research And Application Of Intelligent Control And Monitoring System For Large-scale Cold Storage

As a crucial basic node in the construction of cold chain logistics,large-scale cold storage is also an important infrastructure for food freezing processing,storage and circulation.The refrigeration system is the core system of the cold storage,and its energy efficiency level will greatly affect the overall efficiency of the cold storage.By improving the control efficiency of the cold storage,large fluctuations in the temperature of the storage can be reduced,food deterioration and quality degradation can be prevented,and the purpose of reducing energy consumption and energy saving can be achieved.This paper takes the M-6 large-scale low-temperature cold storage of a non-staple food purchasing center in Lanzhou as the research object,and launches the research and application of the cold storage intelligent control system.The main contents are as follows:(1)Through the analysis of refrigeration technology introduction and control points,the cold storage refrigeration control system is designed,and the temperature control and energy-saving control methods are studied.During the temperature control process,due to the random purchase and retrieval in the cold storage,the temperature in the storage is prone to large fluctuations,which makes the control parameters of the fuzzy controller unable to achieve the optimal,resulting in the fuzzy PID algorithm in the temperature control of the cold storage For problems such as poor adaptive ability and low control accuracy,this paper introduces the idea of variable universe to optimize the fuzzy PID controller,and designs the variable universe fuzzy PID controller.At the same time,a mathematical model is established for the cold storage temperature control system.The MATLAB simulation results show that,compared with the fuzzy PID control method,the variable universe fuzzy PID controller has the characteristics of small overshoot and strong anti-interference.(2)For energy-saving control,through the analysis of energy-saving related issues in low-temperature cold storage,it is determined that most of the refrigeration compressors of cold storage are at partial load,which causes energy waste.Therefore,slide valve adjustment combined with frequency conversion technology is used to affect the compressor capacity.optimize.(3)The cold storage monitoring system with Siemens S7-200 SMART PLC as the core is designed,and the network structure of the control system based on the upper and lower computers is constructed.The lower computer uses a programmable controller(PLC)to detect on-site parameters,control on-site actuators and equipment,and use industrial Ethernet,fieldbus,and Modbus networks for data transmission.The host computer uses an industrial control computer based on the WINCC status software development platform to design and develop a large-scale cold storage control system monitoring interface to realize the real-time monitoring,parameter display and alarm functions of the large-scale cold storage operation process.The operation results of the control system show that the refrigeration control system of the cold storage has reliable operation and stable performance,has realized the automatic,intelligent and visual control of the large-scale cold storage,and has reached the predetermined control goal.