Modeling And Control Of Low Temperature Parabolic Trough Solar Thermal Power Generation Processes

The increasing consumption of fossil energy has led to a sharp decline in reserves.It is urgent to develop and utilize new energy widely.Developing more and more technologies to produce electricity from renewable resources on a small and medium scale is currently a viable solution.Among them,the Concentrated Solar Power(CSP)system can collect solar energy in a large area and then transfer it into heat and electricity,which is considered as a positive and effective solution.In this thesis,each component model of the CSP system is establish.Then,each component model is coupled to develop a dynamic model for the parabolic trough CSP system with thermal energy storage.The parabolic trough collectors are used for solar field to collect solar energy,the gas heater is used for auxiliary backup,the direct two-tank method is used for thermal energy storage,and the Organic Rankine Cycle(ORC)is used for power block.This work emphasizes the interaction of storage component and auxiliary component with other components of the system.In order to overcome the intermittent nature of solar irradiation and adapt to changes in weather conditions,a corresponding energy management strategy is proposed to manage the balance of supply and demand of energy transfer and conversion,so that the system can cope with various weather scenarios(sunny,overcast,cloudy and rainy days).The use of storage and auxiliary backup enables the system to provide smooth heat input to the ORC power block,although there is significant fluctuation in the amount of solar irradiation available.Considering the multivariable and strong coupling characteristics of power generation system,an Offset-free tracking Model Predictive Control(MPC)strategy based on disturbance model is proposed.Then to test the controller performance under the condition that the input disturbances are unchanged and changed.The results show that controlled variables can quickly track set-points without excessive overshoot.Finally,for various weather scenarios,the proposed control strategy combined with the energy management strategy is applied to the entire power generation system for closed-loop simulation to simulate the real operation.The results show that the power generation system can overcome the intermittent nature of solar irradiation,achieve safe and stable operation,smooth output power,and adapt to various weather conditions.