| Photovoltaic array is an important part of photovoltaic power generation systems. It contains many photovoltaic cells. Currently, there are mainly two kinds of models for solar cells: one-diode model and two-diode model. Since the two kinds of models are implicit and nonlinear, which are not conducive to solving. Therefore, in the practical application, they are usually needed to converted into explicit expressions. In resent years, many explicit expressions of VI ? characteristic for one-diode model have been proposed. However, explicit expressions of VI ? characteristic for two-diode model are rarely found in the current literature. Therefore, an explicit VI ? characteristic two-diode model of photovoltaic arrays is needed.In this paper, Lambert W-function is used to model explicit expressions of VI ? characteristic for two-diode model. Firstly, Lambert W-function is used to obtain an explicit two-diode modeling method for solar cells and photovoltaic arrays with bypass diodes. These explicit two-diode models proposed in this paper are accurate. Secondly, this paper presents new explicit expressions for series resistance by using Lambert W-function. The new explicit expressions of series resistance take into account the influence of temperature and irradiance, and the relationship between series resistance and other parameters. It is worth mentioning that no matter one-diode model or two-diode model, the cell parameters can be obtained by only using four electrical parameters, i. e., voltage and current at maximum power point, open circuit voltage and short circuit current. Finally, we select RTC France solar cell, Photowatt-PWP 201 solar module, MSX-60 module, KC200 GT module and SM55 photovoltaic array to validate the operation speed and accuracy of the method proposed in this paper, respectively.Simulation results show that the method proposed in this paper is accurate and fast for solar cells and photovoltaic arrays with bypass diodes at any conditions. |
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