A control method of star-chain statcom based on phase-to-phase power loop

Abstract

The invention discloses a star chain STATCOM based on an interphase power loop and a control method thereof. The system includes a three-phase chain-link converter. One end of the three-phase chain-link converter is connected in star form, and the other end is respectively connected to the ABC three-phase of the AC grid through an inductor. An LC series resonant circuit is arranged between adjacent chain links, and both ends of the LC series resonant circuit are connected to the inductance side of the three-phase chain-link converter. The present invention improves the unbalanced reactive power compensation capability of the star-chain STATCOM by transferring the high-frequency AC voltage component output by the half-bridge converter / full-bridge converter of the three-phase chain link in the LC series circuit; The interphase power channel is added to the star chain STATCOM phase, which improves the power density of the device.

Description

technical field [0001] The invention relates to power electronics technology, in particular to a star chain STATCOM based on an interphase power loop and a control method thereof. 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. [0003] 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 a...

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Problems solved by technology

[0003] 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 industrial frequency transformer is very bulky and does not use the power density of the device to increase

[0004] 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, unbalanced reactive power limited ability to compensate

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