Solar ray collection rate fluctuation analysis with Monte Carlo Ray Tracing method for space solar power satellite

摘要

According to the ideal optical design, the spherical concentrator made by the semi-transparent and semi-reflecting thin film is used in SSPS-OMEGA system. To obtain the continuous power, the PV array should rotate around the spherical concentrator to point the sun when SSPS-OMEGA rotate around the earth on GEO. However, considering the in-orbit assembly, the concentrator is assembled by many planar elements to be approximate to the ideal spherical concentrator. The solar ray collection rate fluctuates in certain scope because the original solar ray path is changed. In addition, planar element is deformed easily by the rotating PV array, which also lead to the fluctuation because the position of the planar element is changed. In this paper, the spherical concentrator is divided into many planar elements by using equal latitude and longitude method. It is studied that the relationship between the number of division layers and the collection rate fluctuation by using Monte Carlo Ray Tracing method. The simulation results indicate that with increasing dividing layers, the collection rate increases and the fluctuation amplitude decreases, which ranges 80.72-83.70% (2.98%) of 24-layers concentrator, ranges 88.45-89.91% (1.47%) of 48-layers concentrator, and ranges 92.46-93.80% (1.33%) of 72-layers concentrator. To solve the deformation of the concentrator, the flexible multibody dynamics model of SSPS-OMEGA is established. Combing the deformation and Monte Carlo Ray Tracing method, it is studied that the relationship between the deformation of the concentrator and the collection rate. The simulation results indicate that the stiffness of 72-layers concentrator is better than 24-layers concentrator and 48-layers concentrator, and the reduction of the collection rate of 72-layers concentrator, which is 0.4%, is less than 24-layers concentrator (1.57%) and 48-layers concentrator (0.81%).