cpvlib: A comprehensive open-source tool for modeling CPV systems

Abstract

The design and simulation of concentrator photovoltaic (CPV) systems necessitate precise modeling tools, for which some commercial and open-source options exist. However, when new technologies or applications need to be modeled, they can present some limitations: lack of documentation transparency and inability to extend existing models, or little flexibility to do it. For instance, the novel hybrid CPV/flat-plate module, conceived by Insolight and developed within the HIPERION project, required the ability to model integrated tracking and dual use of incident irradiance, which was not possible with existing tools. Addressing these issues, cpvlib is introduced as a comprehensive, open-source tool offering modular and adaptable functionalities for CPV-based systems, built as an extension of the popular pvlib python library.

cpvlib's design enables the simulation of various CPV-based configurations, incorporating advanced architectures such as integrated tracking and hybrid CPV-flat plate modules. The library uses PVSyst's utilization factors to model deviations from the single-diode model, accounting for spectral and thermal effects. Its class structure leverages object-oriented programming principles, ensuring ease of use and extension.

The validation of cpvlib is carried out through the modeling and long-term monitoring of Insolight's hybrid Si/III-V translucent planar micro-tracking modules, achieving a root mean square error of 3.5 % in case of Si cells and 2.7 % for III-V CPV cells. The tool accounts for complex behaviors like air mass impact on CPV performance, angle of incidence limits, and light spillage. The annual energy yield for a hybrid module is computed using typical meteorological year data, showcasing cpvlib's practical application.