Research On Room Temperature Control Technology Of Heating System Based On Advanced PID Algorithm

Compared with the developed countries,our country’s current heating energy consumption per unit area on the high side,providing thermal comfort is bad,in the "carbon peak,carbon neutral" strategy under the background,on the premise of guarantee the residents heating demand,energy efficiency,reduce carbon emissions,the development of green,efficient and intelligent heating system is the only way,However,the large hysteresis and strong nonlinearity of the room temperature model cause great obstacles to the room temperature regulation of heating system,and also directly hinder the popularization and application of thermal metering heating mode.Based on the above background,this paper proposes a reliable modeling method for indoor heating system and designs a reasonable indoor temperature control algorithm,so that the indoor temperature can be accurately and quickly stabilized within the comfort threshold,providing theoretical support for the development of China’s heating industry.The specific research contents of this paper are as follows:Firstly,analyzes the operation principle of heating system,introduces the composition of the system function and characteristics of each module,on the basis of previous research,the basic principle of variable flow control strategy are given,which USES the frequency of the inverter control of variable frequency pump,and by changing the radiator flow to realize the real-time control of the heat dissipation of radiator.Secondly,a simulation model of the heating system was built based on Matlab/Simulink,which mainly included the simulation module of room heat load and radiator.The model was verified by a simple test system,and the parameters of the module were corrected.Thirdly,in order to solve the problem of room temperature control,the classical PID algorithm is improved.First,in order to improve the accuracy of the system,a control loop is added,and the classical PID algorithm is improved to double loop cascade PID control.Second,in order to solve the problem of large delay system,puts forward two kinds of solution,a way for joined the differential or intermediate differential feedback correction module,in order to improve the system frequency phase frequency characteristics,improve the system response ability,another is to use Smith forecast to predict the change of the system and prediction in order to advance the system response output to compensate for advanced control system.Based on these two ideas,two advanced PID combined compensation algorithms are proposed,which are differential advance/differential feedback cascade PID control and Cascade PID control algorithm based on Smith predictive compensation.The simulation results show that,compared with the classical PID cascade control,the overshoot,adjustment time and rise time of Smith’s compensation cascade PID control algorithm are increased by 20.21%,64.66% and 34.95% respectively,and the energy saving efficiency of the system is increased by 29.82%.Smith estimates that the temperature fluctuation of the compensated cascade PID control is 0.01.It can be seen that Smith predicts that the compensated cascade PID control has obvious advantages in the dynamic characteristics of the system,ensuring indoor thermal comfort,or energy saving efficiency of the system.Based on the above analysis,Smith estimates that compensating cascade PID control is the best for room temperature control.