Temperature Control Stirtegy Of Indirect Double Tank Heat Storage System In Solar Thermal Power Plant

In order to study the temperature control strategy of the indirect dual-tank heat storage system of the solar thermal power station,this paper comprehensively analyzes its operation logic and determines the synergy relationship of each link of the system temperature control.The analysis shows that the system mainly includes four temperature control links:the temperature control of the high temperature heat transfer fluid outlet of the heat collecting field in the heat storage mode,the temperature control of high temperature molten salt outlet of the high temperature molten salt tank in the heat storage mode,the temperature control of the high temperature heat transfer fluid oulet of the oil and salt heat exchanger in the energy supply mode,the temperature control of the high temperature steam outlet of the steam heat exchanger in the energy supply mode.On this basis,this article carried out mathematical model building and transfer function deduction of the involved components according to various physical laws,including servo heat transfer fluid pump,frequency conversion molten salt pump,high and low temperature molten salt storage tank,molten salt and heat transfer fluid heat exchangers,steam heat exchangers,and solar beat collection fields.It can be used to obtain the comprehensive transfer functions of the four temperature control links based on the synergy relationship.High temperature molten salt's temperature reflects the working conditions of the heat storage system in time,this paper bases on temperature control of high temperature molten salt of the high temperature molten salt tank in the heat storage mode,studies and designs two control strategies,traditional PID control and intelligent PID-adaptive fuzzy control.Put two control strategies on MATLAB/Simulink platform for simulation modeling and testing.The simulation test includes non-ambient simulation test,and based on the measured ambient temperature of a groove type CSP station,set the low temperature(-10?,-5?,0?),and high temperature(5?,10?,20?)environment temperature test.In the non-ambient test,the traditional PID strategy overshoot is 8.6%,the number of oscillation times is 2,and the adjustment time is 19min.The adaptive fuzzy control overshoot is 4%,the number of oscillations is 1,and the adjustment time is 6.3min.In the ambient temperature simulation test,the traditional PID anershoot and the number of oscillations are higher than the adaptive fuzzy control under the two types of ambient temperature.The adaptive fuzzy control of the ambient temperature curves before 100min can drop to the target temperature after reaching the peak and quickly reach the steady state,and no longer experience large low-temperature shock.In the traditional PID test,the temperature fluctuation of this link is higher than that of adaptive fuzzy control at each temperature.Based on the simulation test results,the adaptive fuzzy control strategy has obvious advantages,which can effectively control the high temperature salt temperature in the high temperature molten salt tank.This article can provide a certain reference value for the temperature control of various thermal storage systems of CSP stations.