Novel adaptive maximum power tracking control method under partial shading

Abstract

The invention discloses a novel adaptive maximum power tracking control method under partial shading; a conventional variable-step MPPT method has an excellent effect on a single peak value characteristic searching optimization problem under a uniform lighting condition, yet may fail in processing a multi-peak value searching optimization problem; the invention provides a novel adaptive variable-step MPPT method to solve said problems; the method comprises the following steps: firstly, building a photovoltaic array mathematics model under the partial shading condition; converting the multi-peak value searching optimization problem into single-peak value searching optimization problem according to a voltage section to which the maximum power point is located and special rules presented by an open circuit voltage and a short circuit current; using an improved adaptive algorithm to search the global maximum power point after finding the section. According to simulation results, the algorithm can effectively find the global maximum power point both under a non-shading condition or the partial shading condition.

Description

technical field [0001] The invention relates to the field of photovoltaic power generation, in particular to a maximum power tracking method applied in partial shadows. Background technique [0002] With the progress of society, solar power generation has become one of the main sources of electric energy in our country. Compared with traditional fossil energy, photovoltaic power generation has great development prospects as a pollution-free and renewable new energy. However, the output characteristics of photovoltaic cells are obviously nonlinear with the external environment, and their photoelectric conversion efficiency is very low. Therefore, the maximum power point tracking (Maximum Power Point Tracking, MPPT) technology has become a hot research topic. [0003] So far, various MPPT control strategies have been proposed. The classic methods include constant voltage method, perturbation and observation method, and conductance incremental method. Among them, the conduc...

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Problems solved by technology

However, when the photovoltaic array is shaded, its output characteristics show multi-peak characteristics. At this time, the above MPPT method may fail to find the global maximum power point (Global Peak, GP)

Improved algorithm for maximum power point tracking under partial shadow conditions (Sun Bo, Mei Jun, Zheng Jianyong. Improved algorithm for maximum power point tracking under partial shadow conditions. Electric Power Automation Equipment, 2014, 34(1): p.115-119.) proposed an improvement The incremental conductance method uses the approximate relationship between the open circuit voltage and the maximum power point voltage to find the maximum power point. However, this method needs to search all the voltage intervals where local extreme points may appear to find the MPP, so its dynamic response speed is relatively slow. slow

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