Combining solar cell and optical modeling in multijunction systems

High efficiency solar cell concentrator systems, particularly non-tracking systems, may utilize optical systems that involve lenses, secondary concentrators, dichroic mirrors and other optical components in conjunction with a variety of cells that may be optically and electrically connected in series or parallel configurations. This paper describes the value of combining realistic PV models into a complex optical model, making it possible to simulate the performance of the complete PV system to simplify the task of optimizing the system design. The model also allows for the assessment of many important optics-to-PV interface effects such as angle of incidence of the rays on cell performance. The embedded PV models used are based on readily measured cell performance, which can be characterized external to the complete PV system. Agreement between model predictions and measured performance is presented.