A Novel Photovoltaic String Model Based on the Lambert w Function for Partial Shading Conditions

PV equivalent circuit is essential to describe a PV string under the partial shading condition (PSC). The accuracy of the PV string model will largely determine the effectiveness of the global maximum power point tracking (GMPPT) techniques. This paper proposes a novel PV string model by applying the Lambert W function and modifying the aforementioned two-stage Beta method. Key module is specified in deciding the string current and the linear voltage sources are used for high-irradiated PV modules in order to minimize the errors. Main results for a long PV string under low irradiance conditions are provided to validate the effectiveness of the proposed model.