A Photovoltaic Model With Reduced Computational Time

Modeling partially shaded photovoltaic (PV) systems for online applications such as model-based MPPTs requires a PV circuit model with low computational time to simulate the large number of connected PV units within a reasonable amount of time. Unfortunately, the accurate PV models available in the literature are complex and suffer from high computational time due to their dependence on a transcendental implicit equation. This paper proposes a photovoltaic circuit model featuring lower computational time and comparable accuracy. The model utilizes the accuracy of the practical PV model and reduces the computational time by replacing the model series resistance with a third-degree-polynomial voltage-dependent source. The proposed model mimics the accurate characteristics of the practical model without being dependent on a transcendental implicit equation, thus providing low computational time. The model also introduces a new parameter to enhance the model´s accuracy at low irradiance. The effectiveness of the model is shown by comparing the computational time and accuracy of the proposed model with those of the available models. A case study of partially shaded PV systems shows that the percentage of reduction in computational time improves with increases in the number of PV units in a simulated PV system, providing a clear advantage when simulating large PV systems.