Starlike chained STATCOM with three-port high frequency transformer

Abstract

The invention discloses a starlike chained STATCOM with a three-port high frequency transformer. The starlike chained STATCOM comprises the three-port high frequency transformer, a three-phase chain converter, three LC series circuits and three inductors; one end of a three-phase chain link of the three-phase chain converter is connected to the ABC three-phase of an alternating current power gridthrough one inductor, and the other end thereof is connected to the three-port high-frequency transformer by adopting star connection; the three LC series circuits are respectively connected between three ports of the three-port high-frequency transformer and an inductance end of the corresponding chain link, and the LC series circuit is connected with the corresponding chain link in parallel. According to the starlike chained STATCOM with the three-port high frequency transformer provided by the invention, energy is transmitted in the LC series circuits through high-frequency AC voltage components output by a three-phase chain link half-bridge converter / full-bridge converter, thus the unbalanced reactive power compensation ability of the starlike chained STATCOM is improved; and besides,by using the three-port high frequency transformer, the volume of the transformer is reduced, and the contradiction between the unbalanced reactive power compensation ability of the starlike chained STATCOM and the device power density is solved.

Description

technical field [0001] The invention relates to high-voltage and high-power power electronic technology, in particular to a star chain STATCOM with three-port high-frequency transformer. Background technique [0002] Chained STATCOM has been widely used in the field of power quality management of medium and high voltage distribution networks. It has the characteristics of modularization and easy expansion, and can be directly integrated into medium and high voltage power grids without transformers. The traditional chained STATCOM topology can be divided into star structure and delta structure. Under the same voltage level, the star structure can use fewer units, thereby greatly reducing the complexity of the system, but the unbalanced reactive power compensation capability of this structure very weak. [0003] Invention patents CN201510196420.6 and CN201310101371.4 disclose the method of using zero-sequence voltage injection to realize a small amount of energy exchange betw...

AI Technical Summary

Problems solved by technology

The traditional chained STATCOM topology can be divided into star structure and delta structure. Under the same voltage level, the star structure can use fewer units, thereby greatly reducing the complexity of the system, but the unbalanced reactive power compensation capability of the structure very weak

[0003] Invention patents CN201510196420.6 and CN201310101371.4 disclose the method of using zero-sequence voltage injection to realize a small amount of energy exchange between phases, but due to the constraints of hardware topology, the software method can only perform a small amount of unbalanced reactive power compensation

Invention patent CN201220674796.5 discloses a star-connected chained STATCOM device with unbalanced current compensation function. It uses a power frequency transformer to provide a zero-sequence current loop to realize energy exchange between phases, thereby achieving any unbalanced compensation. However, the structure The power frequency transformer is very bulky, which is not conducive to the improvement of the power density of the device

To sum up, the current unbalanced reactive power compensation software and hardware of the star chain STATCOM have great limitations, which is not conducive to the realization of high power density devices with arbitrary unbalanced reactive power compensation

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