Photovoltaic array maximum power point tracking method based on chaos optimization search

Abstract

The invention discloses a photovoltaic array maximum power point tracking method based on chaos optimization search. By sampling the direct-current voltage Vpv and the current Ipv which are output by a photovoltaic array in real time, the output power p(k) of the photovoltaic array is calculated and compared with the current maximum power value p* prestored by an MPPT controller; if p(k)>p*, the value of p(k) is assigned to p*, and the value of Vpv is assigned to the output voltage x* of the MPPT controller; otherwise, the value of p(k) is abandoned, and the value of p* and the value of x* are kept unchanged. Then, the voltage x* output by the MPPT controller and the voltage Vpv output by the photovoltaic array are added to a summator, and a generated error voltage is added to the in-phase end of the summator after being subjected to the proportion-integration link and then compared with a sawtooth voltage added to the anti-phase end of a comparator, so that the duty ratio of gate drive signals of a switch tube in a DC / DC converter is changed, the parameters of a DC / DC conversion circuit are regulated and controlled, and maximum power tracking control can be achieved. The photovoltaic array maximum power point tracking method based on chaos optimization search is high in tracking speed and control precision.

Description

technical field [0001] The invention relates to a photovoltaic power generation system, in particular to a method for tracking the maximum power point of a photovoltaic array based on chaotic optimization search, using the MPPT method to improve the efficiency of the photovoltaic cell array in the process of photovoltaic power generation, so that the solar energy can be converted into Electric energy output belongs to the technical field of photovoltaic power generation. Background technique [0002] When the photovoltaic power generation system is working, the photovoltaic cell array has a unique maximum power point under a certain temperature and sunlight intensity, but because the output characteristics of the photovoltaic cell array are affected by factors such as load status, sunlight intensity, and ambient temperature, the photovoltaic cell array The output voltage and current of the photovoltaic system will change greatly accordingly, which will make the output pow...

AI Technical Summary

Problems solved by technology

The constant voltage method is a simple maximum power point tracking method. Its advantages are simple control and easy implementation. However, when the temperature changes, the tracking efficiency of this tracking method is not high, and there is a serious power loss.

Both the perturbation and observation method and the incremental admittance method will oscillate near the maximum power point, resulting in partial power loss

Although a single chaotic search method can accurately track the global maximum, if there are many local maxima densely around the global maximum, although the chaotic motion has ergodicity, it often takes a long time to jump out of the local maximum. time, and due to the randomness of chaotic motion, it is possible to jump far when it is close to the global maximum, resulting in a waste of optimization search time

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