Lsis Co., Ltd.

Yonsei University

Tae Sik Nam

Yong Ho Chung

Gum Tae Son

Kyeon Hur

Hee Jin Lee

Seung Taek Baek

Wook Hwa Lee

Jung Wook Park

A static Voltage Ampere Voltage Reactive (VAR) comparator including: a plurality of capacitors being in a Y-connected structure and supplying three-phase alternating current power according to a switching operation; a plurality of bidirectional thyristors connected to the plurality of capacitors in serial to open and close the plurality of capacitors; and a controller, in response to power applied to the static VAR compensator, periodically applying a firing pulse signal to the plurality of bidirectional thyristors reaching to a voltage phase on which a transient current is minimized, wherein, at a point in time when first applying the firing pulse signal to one bidirectional thyristor, the controller applies simultaneously applies the firing pulse signal to the one bidirectional thyristor and other remaining bidirectional thyristors allowing a current to flow on three phases.

Static VAR compensator apparatus and operating method thereof

The present disclosure provides a method for controlling a multilevel converter, the method including, detecting modulation state values and current directions of sub-modules, and designating, by one sub-module, an average number of switching for each period of an output waveform, wherein the step of designating the average number of switching includes, grouping the sub-modules according to being in ON state or in OFF state, comparing the number of sub-modules in previous ON state and the number of sub-modules in OFF state to obtain a difference therebetween, and changing a state as much as the difference, comparing a sub-module of ON state in charged state and in discharged state with a sub-module of OFF state, and changing the compared states of sub-modules of ON state and OFF state.

Method for controlling multilevel converter

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Seoul, South Korea

Tae Sik Nam