A method for tracking maximum power point of photovoltaic array based on shadow detection

Abstract

The invention relates to a maximum power point tracking method for a photovoltaic array based on shadow detection. The maximum power point tracking method comprises the following steps: firstly, carrying out shadow detection on an illumination image of the surface layer of the photovoltaic array to obtain shadow detection information; secondly, calculating a proportionality coefficient between open-circuit voltage and maximum power point voltage of the photovoltaic array; thirdly, respectively tracking approximate global maximum power point voltage of the photovoltaic array for two situations that shadow exists and the shadow does not exist according to the shadow detection information; fourthly, tracking the global maximum power point voltage of the photovoltaic array according to the approximate global maximum power point voltage. The maximum power point tracking method disclosed by the invention has the advantages of high tracking speed and less power loss.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic power generation, and in particular relates to a method for tracking the maximum power point of a photovoltaic array based on shadow detection. Background technique [0002] In a large-scale photovoltaic power generation system, a photovoltaic array is composed of several photovoltaic modules connected in parallel. Its output characteristics are affected by factors such as external light intensity and temperature, and have complex nonlinear characteristics. When the surface of the photovoltaic array is evenly illuminated, that is, there is no shadow, its power-voltage (P-V) curve presents a single-peak characteristic, and there is a global maximum power point; when the surface of the photovoltaic array is unevenly illuminated, that is, there is shadow, the P-V curve has multiple a local maximum power point. In practical applications, the photovoltaic power generation system needs to use corr...

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Problems solved by technology

[0003] The traditional maximum power point tracking methods mainly include perturbation and observation method, conductance incremental method, optimal gradient method and fuzzy control method, etc., but in the actual engineering application of large-scale photovoltaic power generation system, the power loss and shadow state As a result, the stability of the control system decreases and other issues. Most of them use a constant voltage method to control the output power of the photovoltaic array, regardless of the maximum power point offset in the shadow state, resulting in a decrease in power generation efficiency.

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