Photovoltaic array multi-peak maximum power point tracking method

Abstract

The invention provides a photovoltaic array multi-peak maximum power point tracking method. According to the method, a power curve of an array is rapidly sampled based on the characteristics of a photovoltaic cell, power of each peak value point is estimated, the region where a global peak value is located is determined, single-peak MPPT is conducted in the region, and then global multi-peak MPPT is achieved. The method mainly includes the following steps of firstly, changing an output voltage of the array, and rapidly sampling the power curve of the array; secondly, analyzing the peak value condition of the array and estimating the size of peak values according to the characteristic parameters of a cell panel and sampling data, and determining the region where the global peak value is located; thirdly, conducting single-peak MPPT of a variable step size perturbation and observation method in the region; fourthly, repeating the method regularly or repeating the method when the actual power much deflects from the calculated maximum power. By means of the method, only a plurality of points on the power curve of the photovoltaic array are sampled based on the characteristic parameters of the photovoltaic cell panel, estimation values of all peak values can be obtained through simple operation, the region where the global peak value is located is rapidly positioned, and the method has the advantages of being clear in concept, simple in control structure, easy to implement in engineering and the like.

Description

technical field [0001] The invention relates to a photovoltaic power generation system and belongs to the technical field of maximum power point tracking control of photovoltaic power generation systems. Background technique [0002] Photovoltaic grid-connected power generation makes large-scale utilization of solar energy possible. Facing the high cost of power generation, improving system efficiency has always been a research hotspot. For a photovoltaic array composed of multiple photovoltaic cell modules connected in series and in parallel, when there are local shadows (clouds, trees, buildings shaded), there will be multiple local peaks (maximum values) in the output power curve of the photovoltaic array. The traditional maximum The power point tracking technology tends to converge to a local peak, resulting in power loss of the photovoltaic array. [0003] Therefore, in order to allow the photovoltaic array to output as much power as possible when partial shadowing occ...

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Problems solved by technology

[0004] The purpose of the present invention is to propose a method for tracking the multi-peak maximum power point of a photovoltaic array, which solves the problem that there are multiple peaks in the local shadow of the photovoltaic array, and the maximum power tracking strategy converges to the local peak, which leads to power loss. Output power of photovoltaic array

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