A photovoltaic variable step size mppt control method based on prediction technology

Abstract

The invention provides a photovoltaic variable step size MPPT control method based on prediction technology, which belongs to the technical field of photovoltaic MPPT fast tracking. The control system of the control method includes a photovoltaic cell group, an MPPT controller, a load and a DC-DC circuit connected to the load. The control method of the present invention can analyze the working state of the controller according to the sampling voltage and current value obtained in each sampling cycle of the controller, and can predict the maximum power point (MPP point) on the output characteristic curve of the battery under the corresponding light intensity when the light intensity changes. ) voltage and current values, so as to calculate the optimal output duty cycle, so that the system can quickly reach the optimal power point (GMPP point), and then quickly and stably track from the GMPP point to the MPP point with variable step size, This method can not only solve the problem that the MPPT controller is prone to misjudgment when the light intensity changes, but also can take into account the response speed and steady-state accuracy of the MPPT controller.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation, in particular to a method for fast tracking of photovoltaic MPPT. Background technique [0002] Energy is an important material basis for human production and survival. In order to meet the needs of industrial development, people exploit fossil fuels such as coal, oil, and natural gas in large quantities. Due to the non-renewability of these fossil energy sources, many countries are already facing the problem of energy depletion. In order to solve the energy crisis, all countries are looking for alternative energy sources. As a kind of clean energy, solar energy has the advantages of better stability, service life, and simple maintenance compared with wind energy, and has been widely used around the world. [0003] The power generation efficiency of photovoltaic cells is affected by many uncontrollable external environments, such as light intensity and temperature, among wh...

AI Technical Summary

Problems solved by technology

The traditional P&O and INC algorithms both use a fixed step size for disturbance. Since the set value of the step size is fixed, the tracking effect is not good.

When the step size is set larger, larger shocks will occur in a stable state; when the step size is set smaller, it cannot be quickly disturbed to the maximum power point when the environment changes

At the same time, when the cloud layer moves to block the sunlight, resulting in continuous and slow changes in the light intensity, the traditional algorithm is prone to continuous misjudgment, and it is easy to cause a large energy loss at this time.

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