Tracking method for maximum power point in photovoltaic grid-connected inverter

Abstract

The invention relates to a tracking method for the maximum power point, applied in an independent photovoltaic grid-connected power generation system. According to the tracking method, the maximum power point of a solar cell panel is tracked in a variable step size mode on the basis of the conductance increment method, so that the problem that speed and accuracy are ambivalent in a traditional conductance increment method is solved. According to the tracking method, the step size of a work point can be achieved in an automatic regulating mode according to characteristics of the solar cell panel, and therefore when the work point is far away from the maximum power point, the step size is larger, and tracking speed is increased; when the work point is close to the maximum power point, the step size is reduced so that the oscillation phenomenon nearby the maximum power point can be reduced, and therefore efficiency is improved. The step size correcting MPPT algorithm provided by the tracking method can solve the conflicting problem, and accuracy and speed of MPPT can be improved easily and effectively. The tracking method has the advantages of being accurate in control and high in response speed, and can be suitable for rapid reaction occasions where sunshine and temperature change suddenly, and the situation of continuous changes of the sunshine can be stably tracked.

Description

technical field [0001] The invention relates to a maximum power point tracking method applied in an independent and grid-connected photovoltaic power generation system, and belongs to the technical field of photovoltaic power generation system control. Background technique [0002] The independent photovoltaic power generation system has its own energy storage link, which mainly solves the power supply problem in remote areas without electricity; the grid-connected photovoltaic power generation system is directly connected to the grid, like a small distributed power station, feeding the collected electric energy into the grid. [0003] Photovoltaic cells use the photoelectric effect to generate current, and the current-voltage curve of a solar panel is as follows figure 1 As shown, the power-voltage characteristic curve of the solar panel is as follows figure 2 As shown in the figure, it can be seen from the figure that in a certain environment, there is a maximum power po...

AI Technical Summary

Problems solved by technology

[0009] The technical problem to be solved by the present invention is: to propose a maximum power point tracking method in a photovoltaic grid-connected inverter, which is based on the incremental conductance method and uses a variable step size to track the maximum power point of the solar panel to solve The problem of the contradiction between the tracking speed and accuracy of the traditional conductance incremental method

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