A multi-peak state maximum power point tracking method for solar photovoltaic strings

Abstract

The invention provides a method for tracing a maximum power point in a multi-crest state of solar photovoltaic strings, and belongs to the field of photovoltaic power generation. The method comprisesthe following steps: 1) derivatively calculating a current value Im1 at the position of the maximum power point by using a first wave crest five-parameter and dP / dI; 2) calculating a voltage value Um1of the maximum power point of a first wave crest by using the first wave crest five-parameter and Im1; 3) calculating the maximum power point Pm1= Im1* Um1 of the first wave crest; 4) calculating themaximum power points of all follow-up wave crests, and comparing the global maximum power point PM; 5) modulating output voltage to be UM; and circulating step 1) to step 5) periodically to trace theglobal maximum power point of the multi-crest strings. Direct calculation on the maximum power points of all the wave crests in the multi-crest state of the photovoltaic strings and global maximum power point tracing are realized, the method has the advantages of low influences of a calculating process to output of the strings and high maximum power point calculating precision, data guarantee isprovided for follow-up string working state analysis and fault diagnosis, and the engineering practicability is high.

Description

technical field [0001] The invention relates to a method for tracking a maximum power point in a multi-peak state of a solar photovoltaic string, belonging to the field of photovoltaic power generation. Background technique [0002] In recent years, my country's photovoltaic industry has developed rapidly, and its installed capacity has increased significantly. With the passage of time, the photovoltaic industry is bound to gradually enter the post-photovoltaic era in which the goal is to ensure the stable and efficient operation of power stations, and the daily operation and maintenance of photovoltaic power stations is the main task. Since the average lifespan of existing photovoltaic power plants is about 25 years, and photovoltaic systems usually operate unattended, system failures will reduce output power and affect the normal operation of the entire system. [0003] In practical applications, various faults may occur in the photovoltaic power plant system, which will ...

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Problems solved by technology

[0006] The main purpose of the present invention is to provide a method for tracking the maximum power point of a solar photovoltaic string in a multi-peak state based on the five parameters of the components corresponding to the peaks in the string in the multi-peak state, so as to solve the problem of multiple peaks in the photovoltaic string. Calculation of the maximum power point of each wave peak and tracking of the global maximum power point in the peak state

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