Development of a compound power generation model for bifacial photovoltaic modules under partial shading conditions

Bifacial photovoltaic (bPV) modules experience non-uniform solar irradiance distribution on both the front and rear sides due to self-shading, mutual shading, and external shading, which affect their performance and reliability. Therefore, it is essential to develop an accurate power model under partial shading conditions (PSC). Existing power generation models for bPV modules, usually based on bifaciality, fail to account for the electrical mismatch between the shaded and the non-shaded solar cell areas and the dynamic variations in electrical performance of both sides, both of which lead to the overestimation of power generation. To address the limitations, this paper proposes a novel compound power generation model, which develops a dual current-source sub-model (DCSM) to consider solar cell mismatch and employs a parallel equivalent circuit sub-model (PECM) to capture the dynamic variations in the electrical performance of both sides. By integrating the two sub-models, the five parameters of the bPV cell under PSC were obtained to derive the module's power output. The proposed model accurately simulates the power output of bPV modules in outdoor experiments. Compared to the traditional model, which exhibits mean relative errors of 28.24 %, 29.58 %, 61.61 %, and 61.40 % under two shading types in sunny and cloudy conditions, the proposed model reduces all errors to below 5 %. Furthermore, this study compared the performance of full-cell and half-cell bPV modules under identical PSC from different perspectives, including shading degree, number of cells, and shading direction. The findings offer valuable insights for optimizing bPV module installation and deployment to mitigate shading-related risks.