A Method for Eliminating the Parallel Dilution Effect of Multiple Inverters and an Islanding Detection Method

Abstract

The invention discloses a method for eliminating the parallel dilution effect of multiple inverters in the field of electrical equipment and electrical engineering and an island detection method, using a phase-locked loop to use the time when the output phase angle crosses zero as multiple parallel inverters At the starting position of the disturbance in each cycle, the synchronous disturbance of multiple parallel inverters is realized. After the synchronous disturbance, the direction of the voltage frequency deviation at the common point is consistent; and the voltage obtained by the parallel inverters comes from At the common point of the same bus, after the phase-locked loop converges, the obtained disturbance phase is also the same. The invention improves the island detection method using phase disturbance, and finds a phase-locked loop-based method that can make multiple inverters The islanding detection method, which is synchronously disturbed by the converter and easy to extract the disturbance, improves the islanding detection method.

Description

technical field [0001] The invention relates to a plurality of inverters connected in parallel, in particular to a method for eliminating the dilution effect of parallel connection of a plurality of inverters. Background technique [0002] With the increase of distributed power grid-connected capacity, the power supply system will cause some serious problems due to the interruption of power supply of the large power grid. Among them, the island effect is a problem that cannot be ignored. When the distributed generation system is in an island operation state, if it cannot be detected and removed in time, it will seriously threaten the personal safety of maintenance personnel, affect the power quality and even damage the power supply equipment. Therefore, the distributed generation system based on grid-connected inverters requires the islanding detection function. [0003] The current island detection technology is divided into three categories: local passive method, local ac...

AI Technical Summary

Problems solved by technology

Although some disturbance methods can effectively detect isolated islands under the condition of a single unit connected to the grid, in the case of multi-unit parallel connection, the mutual influence between the inverters causes the disturbances to be out of sync, and each disturbance may cancel each other out due to the And produce dilution effect, so that the detection effect is not obvious

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