Maximum power point tracking (MPPT) control system and MPPT control method of modular photovoltaic array

Abstract

The invention discloses a maximum power point tracking (MPPT) control system and an MPPT control method of a modular photovoltaic array. The control system comprises photovoltaic modules, a photovoltaic module controller, a particle swarm operation module, a fuzzy self-optimization control module, a controller, a convertor and a load, wherein the photovoltaic modules are connected with the photovoltaic module controller which is connected with the particle swarm operation module and the fuzzy self-optimization control module, the particle swarm operation module and the fuzzy self-optimization control module are connected, the particle swarm operation module and the controller are both connected with the convertor, the fuzzy self-optimization control module is connected with the controller, and the convertor is connected with the load. A particle swarm optimization is used for tracking an optimal power point of each independent photovoltaic module of the photovoltaic array, and then a multivariable fuzzy self-optimization algorithm is used for achieving MPPT control of the whole photovoltaic array.

Description

technical field [0001] The present invention relates to the field of solar photovoltaic power generation, in particular to an MPPT (Maximum Power Point Tracking, Optimum Power Point Tracking) control system of a modular photovoltaic array and a control method thereof. Background technique [0002] Conventional MPPT implementation methods include constant voltage method, perturbation observation method, conductance increment method, etc. The constant voltage method uses 70% to 90% of the open circuit voltage of the solar cell as the voltage corresponding to the optimal power point to calculate the optimal power. However, since the ratio of the optimal power point voltage to the open circuit voltage is not a certain value, there is A certain error, so the constant voltage method is not a real optimal power tracking method. [0003] The disturbance observation method is to first let the solar cell work at a certain voltage, and record the power of the solar cell at this time a...

AI Technical Summary

Problems solved by technology

Disadvantages of the disturbance and observation method: at any moment, the output optimal power point oscillates back and forth near the real optimal power point, which directly leads to voltage or current fluctuations on the load

Disadvantages of the conductance incremental method: Since the search for the optimal power point is directly realized by changing the step size each time, the search for the optimal power point by the system will become very slow if a fixed step size is used.

The implementation method is more complicated, and the program needs multi-branch judgment. If you accidentally set the parameters in each branch judgment, MPPT may be limited to a local range.

[0005] There are some shortcomings in the above methods, that is, the initial search for the optimal power point takes a relatively long time, and when the ambient temperature or the amount of sunlight changes sharply in a short time, it will have a relatively oscillating effect

At the same time, the above methods are basically only suitable for simple series-parallel photovoltaic arrays, and cannot efficiently search for the optimal power point for modular photovoltaic arrays.

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