Photovoltaic system maximum-power-point tracing and optimizing method

Abstract

The invention provides a photovoltaic system maximum-power-point tracing and optimizing method. The method includes the steps of firstly, obtaining a photovoltaic array mathematic model according to a photovoltaic cell equivalent circuit, and establishing a target function and a constraint function; secondly, establishing a Lagrange function according to the target function and the constraint function, solving the Lagrange function, and determining the search direction dk and the Lagrange multiplier lambda k of the Lagrange function; thirdly, conducting searching according to the improved Armijo criterion, determining the compensation factor of voltage at the maximum power point, and calculating a new iteration point; fourthly, renewing a Hessian matrix if the voltage convergence discrimination does not meet the end condition till the optimal voltage solution at the maximum power point is obtained. By means of the method, the problems that a classical maximum-power-point tracing method neglects external condition changes, is prone to oscillation at the maximum power point and is complex to implement can be solved. Power loss caused by external environment changes can be reduced, and rapid, stable and accurate tracing of the voltage at the maximum power point is achieved.

Description

technical field [0001] The invention relates to the technical field of development and utilization of clean energy, and especially has important significance for improving the utilization rate of solar energy and the power generation efficiency of a photovoltaic system. Background technique [0002] With the increasing environmental and energy pressure, the development and utilization of clean energy has gradually become the mainstream, among which solar energy stands out in the field of new energy power generation with its inexhaustible, inexhaustible and non-polluting advantages. But the main problem is the efficiency of solar power generation. Since the external environment is constantly changing, the output power of the photovoltaic array also changes. Therefore, one of the main ways to solve this problem is to perform maximum power point tracking. [0003] For the maximum power point tracking problem, domestic and foreign scholars have obtained many research results, su...

AI Technical Summary

Problems solved by technology

However, the main problem is the efficiency of solar power generation. Since the external environment is constantly changing, the output power of the photovoltaic array also changes. Therefore, one of the main ways to solve this problem is to perform maximum power point tracking.

Among them, the constant voltage method has been widely used because of its simple structure, easy implementation, and good stability of the system operating voltage, but it ignores many external conditions, and the result is not accurate enough. In order to overcome its shortcomings, we use the present invention to its optimize

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