Active P-V characteristic correction method and device for photovoltaic component

Abstract

The invention discloses an output P-V characteristic correction method for a photovoltaic component. The method realizes even grouping of photovoltaic battery elements connected in series in the photovoltaic component to ensure equal output voltage of each battery element group. Based on the fact that the photovoltaic battery elements are evenly divided into three groups, the invention provides the correction circuit which comprises capacitor bridge arms connected in parallel and two MOSFET bridge arms, wherein each capacitor bridge arm consists of three capacitors connected in series; the two MOSFET bridge arms have identical structures and each MOSFET bridge arm consists of a P-channel MOSFET drain electrode and an N-channel MOSFET drain electrode which are connected in series; the P-channel MOSFET drain electrode in the first MOSFET bridge arm is connected with the connection point of the two adjacent capacitors through an electrical inductance; and the P-channel MOSFET drain electrode in the second MOSFET bridge arm is connected with the connection point of the other two adjacent capacitors through another electrical inductance. The output P-V characteristic correction method corrects photovoltaic component P-V characteristic with a plurality of power extreme points under local shadow into a single power extreme point; moreover, the method adopts a maximal power point tracking method to ensure that the system operates at the maximal power point, thereby increasing the output power of the photovoltaic component.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation, in particular to an active P-V characteristic correction method and device for photovoltaic components in a photovoltaic power supply system, which are used to ensure that the photovoltaic components have only one maximum power point under partial shadow conditions. Background technique [0002] As one of the important strategies to solve the global energy crisis and environmental problems and achieve sustainable development, photovoltaic power generation technology using clean and renewable sunlight as energy has attracted the attention of countries all over the world. [0003] In the photovoltaic power generation system, since the current-voltage (I-V) and power-voltage (P-V) characteristics of the photovoltaic module output are nonlinear and have a maximum power point, and its maximum power point changes with factors such as light and ambient temperature, in order to To m...

AI Technical Summary

Problems solved by technology

However, there are buildings and trees around a large number of photovoltaic power generation systems, and the local shadows they form on the photovoltaic modules not only cause the output power of photovoltaic modules to decrease, but also have multiple extreme points in their P-V characteristic curves, such as figure 2 Shown is the P-V characteristic curve of the photovoltaic module under partial shading conditions

Since there are multiple extreme points in the P-V characteristic curve of photovoltaic modules, the commonly used perturbation observation method and admittance increment method tend to fall into local extreme points, which cannot ensure that photovoltaic modules operate at the true global maximum power point, resulting in energy loss

[0005] In order to improve the output power of photovoltaic modules with multiple power extreme points, at present, people have carried out some research mainly on improving and proposing new global maximum power point tracking algorithms. These methods have a common problem: when photovoltaic modules appear multiple After an extreme point, these methods can only passively search for the current global maximum power point of the photovoltaic module. At this time, the power of the global maximum power point is much smaller than the current output power of the photovoltaic module. Implementation is more complicated

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