Multi-objective Optimization Of Photothermal And Photovoltaic Hybrid System Based On NSGA-? Algorithm

This topic uses the NSGA-? algorithm to achieve multi-objective optimization of the leveling energy cost LCOE,capacity factor CF and initial investment C' of the photothermal photovoltaic hybrid power system.Firstly,the theoretical analysis of the trough-type CSP system and the photovoltaic power generation system was carried out,and the mathematical model was established.Based on this,the TRNSYS software and Simulink software were used to construct the simulation platform of PTC and PV system respectively,and combined with Jiuquan.The regional weather parameters were simulated and verified.Secondly,in order to determine the objective function of multi-objective optimization,the mathematical model of technical economic evaluation of photothermal photovoltaic hybrid power generation system was improved based on previous studies,including leveling energy cost LCOE.,capacity factor CF and initial investment in unit capacity;finally,the NSGA-? algorithm is written in MATLAB software,the determined objective function and decision variable are encoded,and the NSGA-? is called to set up TRNSYS and Simulink.The PTC and PV power generation system models perform multi-objective optimization and output optimization results.Based on the simplified mathematical model of technical and economic evaluation,the decision variables affecting the three objective functions are determined and the scope of the variables is defined.The simplified model was simply verified by SAM software,and the deviation percentage was less than 4%.It can be considered that the mathematical model has higher evaluation accuracy.The model is used to simulate the independent trough photothermal system,photovoltaic power generation system and photothermal photovoltaic hybrid power generation system respectively.The simulation results show that the independent trough photothermal power generation system can basically meet the base load demand and achieve high matching power supply.The capacity factor is 38.2%.The leveling power cost of the photothermal photovoltaic hybrid power system(photothermal installed capacity 35 MW,solar multiple 2.0,photovoltaic installed capacity 35 MW,TES thermal storage system capacity 7.5h)is about 1.07 yuan / MWh,and the capacity factor is about 72.3%.The capacity factor of the independent trough solar thermal power generation system(with 7.5 hTES heat storage device)is 41.2%.It can be seen that the hybrid power generation system has a better capacity factor,and the initial investment in the leveling power cost and unit capacity is much lower than that of the independent trough type photothermal power generation system.Therefore,the trough type photothermal photovoltaic hybrid power generation system has high research value.It can be seen from the results of the three-object analysis that the increase in PV cost reduces the advantages of the hybrid system,forcing the PV to PTC power ratio to increase.This is because one of the goals is to minimize initial investment,and the initial investment should be minimized by a higher PV to heat ratio and a lower heat storage ratio.For example,for a PTC+ photovoltaic power plant(considering a 35 MW trough solar thermal power plant with a PV cost of 7.8yuan/W),the optimal solution for dual-target optimization(LCEO,CF)is about 48 MW for PV and 11.982 h for TES,three The target optimal solution is about 58 MW for PV and the TES capacity is 9.729 h.If the initial investment is included as the third target,the cost of designing the power station is lower,the LCOE is at the same level,but the capacity factor is significantly reduced.When comparing the performance of these hybrid systems with independent trough CSP systems,the advantages of hybrid power systems are fully demonstrated.