摘要:Multi-junction solar cells play an important and significant role in the Concentrated Photovoltaic (CPV) Systems. Recent developments in Concentrated Photovoltaic concerning high power production and cost effective- ness along with better efficiency are due to the advancements in multi-junction cells. Boeing SpectroLab Inc. has introduced a Multi-junction solar cell employing tunnel junctions which improves efficiency up to 40%. This paper presents a simulation model of the generalized Multi-junction solar cell. The model adopts a mathematical approach in order to simulate and investigate the cell characterization curves including current density and power curves with respect to the applied voltage for different concentration levels and number of junctions and by varying the material properties of the multi-junctions and the tunneling layer. The proposed simulation model simulates the performance characteristics of two different natures of multi-junction solar cells including InGaP/GaAs Dual-junction Solar Cell (DJSC) with tunneling layer of InGaP and InGaP /GaAs/Ge Triple-Junction Solar Cell (TJSC) with tunneling layer of GaAs. Simulation results are presented in this paper which is in agreement with experimental results. Key–Words: Modeling, Multi-junction Solar Cell, Simulation, Tunnel Junction