Maximum power point tracking method of photovoltaic power generation system

Abstract

The invention provides a maximum power point tracking method of a photovoltaic power generation system. The method includes the steps of S1, building a photovoltaic power generation system hardware model; S2, collecting photovoltaic power generation system open-circuit voltage Uoc; S3, sampling the input voltage U(k) and input currents I(k) of the photovoltaic power generation system; S4, calculating the voltage variation, current variation and step size variation of the photovoltaic power generation system; S5, judging the voltage variation and the current variation, and using different manners to adjust the step size variation of a conductance increment method so as to adjust the input voltage of the photovoltaic power generation system to allow the actual working power point of the photovoltaic power generation system to be close to the maximum power point. By the method, the tracking response time of an MPPT control module is further reduced, sharp attenuation of input power is avoided, fluctuation of output power is reduced, and a tracking control effect is evidently improved.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation, in particular to a maximum power point tracking method for a photovoltaic power generation system. Background technique [0002] The development and utilization of new energy is a hot spot in the world today, and solar energy, as a clean and efficient renewable green energy, has become the first choice for the development of new energy. Solar photovoltaic power generation has also become an emerging energy industry that has developed rapidly in recent years. In the field of solar grid-connected power generation technology, it is necessary to use a solar photovoltaic grid-connected inverter to convert the direct current generated by the solar cell into an output alternating current with the same frequency and phase as the grid, and at the same time optimize the output power of the solar cell. However, due to the nonlinear characteristics of solar cells, the maximum power and...

AI Technical Summary

Problems solved by technology

When the external conditions change suddenly, the power of the system is likely to change suddenly, causing the system to be unstable. In serious cases, the control algorithm will collapse and the voltage cannot be adjusted normally.

A single method has been limited in use and needs to be improved; a combination of simple methods also needs to improve the response time of system adjustment

For these two situations, there are corresponding variable step size methods to improve, but there is still a lot of room for improvement in the flexibility of step size change adjustment during use

[0005] At present, the Chinese patent application number 201210414400.8 discloses a dual-mode maximum power point tracking method based on improved step size, which uses a combination of conductance incremental method and fixed voltage method to track the maximum power point of the photovoltaic power generation system, but There are also the following problems. When the actual operating point is located on the right side of the maximum power point or when the external conditions change suddenly, the output power of the photovoltaic power generation system will be greatly affected and will be rapidly attenuated, resulting in system instability.

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