Optical study of a cocktail structural Space-based Solar Power Station

SPS-ALPHA as the most innovative and practical concept of Solar Power Satellite (SPS), has been widely concerned in the world. It adopts axisymmetric sigmoid curve-based/cocktail shape as the entire structure composed by several thousands of hexagonal "Reflectors and Deployment Modules" (RDM) that enables extremely high modularity and low cost of machining/space transport. SPS-ALPHA system, on the whole, can be treated as a dense array concentrated photovoltaic (DA-CPV) system. The blocking shadow effect and cosine effect of ray path exist that make the optical efficiency fluctuate with different tracking angles, resulting the trade-off exists between optical efficiency and irradiance uniformity. The current study aims to find the optimal design parameters of RDM when high optical efficiencies and stable irradiance distribution are both achieved for effective PV layout design. To meet this target, Ant Colony Optimization (ACO) algorithm combined with dynamic source-target mapping was adopted to find suitable aiming vectors of modular reflectors. The optical transmission characteristics under different incident degrees were investigated using a two-step Monte-Carlo ray tracing (MCRT) method. Afterwards the optimized results and sensitivity analysis for RDM would be undertook. The article can provide basic data and reference for engineering constructions of SPS-ALPHA in next step.