Photovoltaic power generation system MPPT algorithm based on voltage pre-estimating method

Abstract

A photovoltaic power generation system MPPT algorithm based on a voltage pre-estimating method is a maximum power point tracking algorithm applied to a photovoltaic array under complicate illumination conditions. The photovoltaic array is in a DMPPT circuit structure and a simplified equivalent output feature curve of individual photovoltaic cell mode in the photovoltaic array can be achieved; and a computational formula of work voltage pre-estimating value of the photovoltaic array formed by a serial connection of two photovoltaic cell sets under different light strength is achieved. In the photovoltaic power generation system MPPT algorithm based on the voltage pre-estimating method, the photovoltaic system is designed to be in a DMPPT circuit structure; a photovoltaic generation system output feature of the structure is employed to reckon the optimal voltage range of the work points of the photovoltaic array according to the feature curve principle; the optimized voltage pre-estimating value enables the system to effectively skip a secondary merit; after the optimal voltage range is determined, a P&O method is combined; and maximum power point tracking algorithm under complicate illumination conditions can be realized.

Description

technical field [0001] The invention relates to an MPPT algorithm for a photovoltaic power generation system based on a voltage estimation method, and relates to the application field of solar photovoltaic power generation. Background technique [0002] In photovoltaic power generation systems, traditional maximum power tracking (MPPT) algorithms, such as constant voltage method (CVT), conductance incremental method (INC) and perturbation and observation method (P&O), can achieve ideal Track results. However, in the practical application of photovoltaic power generation, it is difficult to ensure the uniform distribution of light. Due to the influence of clouds, tree shade, dust, etc., the photovoltaic array is located in a complex light intensity. When the photovoltaic array is located in complex lighting, there will be a mismatch between components receiving different light intensities, and in the case of bypass diodes, there will be multiple peaks in the P-U characterist...

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Problems solved by technology

[0003] Aiming at the limitations of the traditional MPPT algorithm applied to photovoltaic power generation systems under complex lighting conditions, the current related solutions are: Aiming at the mismatch problem caused by the influence of shadows on photovoltaic cell arrays, it is proposed to use parallel supercapacitors to improve the output of the array characteristics, but did not consider the actual situation such as long shadow duration; in addition, there are related studies that use a photovoltaic power generation system with a distributed maximum power tracking (DMPPT) circuit structure to overcome the problem of system output reduction under complex lighting conditions. The DMPPT circuit structure can indeed improve the operating efficiency of the system, but the research on the complete MPPT algorithm is still immature

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