The Study of Heat Exchange Station Heating System and the Design of Intelligent Control Program
|School||Liaoning University of Science and Technology|
|Course||Control Theory and Control Engineering|
|Keywords||Heat Exchange Station Secondary Supply Return Water Temperature Set-point Dynamic Model Single Neuron Adaptive PID Decoupling Control|
With the development of social modernization, energy-saving control applying in various fields has been widely concerned. Based on the study of heat exchange station process, control theory and system features, combining with practical engineering background, this paper proposes the system control requirements of heat exchange station heating system comprehensively with the heat exchange station as a control object. For the control requirements of heat exchange stations, this paper proposes the forecasting control program of secondary supply-return water temperature set-point, the decoupling control program of secondary supply-return water temperature, pressure control program of secondary supply-return water and pressure control program of secondary -net constant point.According to outdoor temperature, providing secondary supply-return water temperature set-point timely and reasonably is the precondition of achieving on-demand heating and energy-saving operation. Considering the meteorological data, engineering practice, people’s daily living habits and other conditions, the forecasting system of secondary supply-return water temperature set-point has been designed from four steps, respectively the weather forecast updated system, dividing the time period of secondary supply-return water temperature timely and reasonably, determining the average outdoor temperature in the time period, finally determining secondary supply-return water temperature set-point. In the form of feedback, this system sends the point to secondary supply-return water temperature decoupling control system, which reduces the large-delay feature of heat exchange system.Based on the physical mechanism of heat exchanger, this paper builds the coupling relationship mathematical model among the primary side water flow, water flow secondary, secondary supply water temperature and secondary return water temperature for the simulation of decoupling control on secondary supply-return water temperature. Based on heat exchange station mathematical model, this paper makes a simulation on secondary supply and return water temperature decoupling control system with three methods, respectively conventional PID, the single neuron adaptive PID and the single neuron adaptive PID based on learning algorithm for quadratic performance. This has been studied from three situation, respectively the change of secondary supply water set-point, the change of secondary return water set-point and disturbed by the water temperature. That verifies the three control methods feasibility and rationality, of which the advantages and disadvantages have been summarized.