Hyosung Heavy Industries Corporation

Other

Lg Electronics Inc.

Yonsei University

Kim, Hee Jin

Hur, Kyeon

Jae Sik Kang

Sang Min Kim

Hee Jin Kim

Kyeon Hur

Dong Su Lee

Jin Ha Choi

Do Yong Ha

Jong Seo Na

Hyung Jun Kim

Ki Bum Kim

Young Min Park

Suk Jin Choi

Jin Bae Na

Ho Jong Jeong

Tae Kuk Ko

Si Kyong Sung

Hyun Chul Jo

Young Jin Hwang

Jae Young Jang

Ju Yong Jung

A method of controlling output levels of an MMC converter to reduce fluctuation in a power grid frequency, which adjusts an output level of the MMC converter in response to a change in a power grid frequency of a power grid system in the MMC converter connected to a grid system, is proposed. The method includes a detection step of detecting a power grid frequency of a grid connected to the MMC converter in real time, a comparison step of comparing the detected power grid frequency with a preset reference power grid frequency, and an adjustment step of adjusting a number of output levels of the MMC converter to reduce a difference between the detected power grid frequency and the reference power grid frequency when the detected power grid frequency and the reference power grid frequency are different from each other.

Method for controlling output level of modular multilevel converter for reducing power system frequency change

A modular multilevel converter (MMC) includes multiple converter arms, each converter arm having: N submodules connected to each other in series, N being an integer equal to or greater than 2; and a circuit opening unit connected to the N submodules in series to open a circuit of the converter arm, wherein the N submodules has n submodules including full-bridge circuits and N&#x2212;n submodules including half-bridge circuits, n being less than N.

Modular multi-level converter and DC failure blocking method therefor

The present invention relates to an MMC converter system which can quickly cut off fault current by installing a plurality of disconnecting switch units on a line connected between two MMC converter devices. The MMC converter system comprises: a first MMC converter device including a plurality of serially connected sub modules; a second MMC converter device including a plurality of serially connected sub modules; a first disconnecting switch unit installed on a line between the first and second MMC converter devices; and a second disconnecting switch unit connected in series to the first disconnecting switch unit on the line, wherein each of the first and second disconnecting switch units comprises a mechanical switch installed on the line so as to open and close the line and a diode connected in parallel to the mechanical switch, and the two diodes are installed in opposite directions to each other.

Modular multilevel converter system

The method of winding superconducting wire comprises a winding method comprising: winding the superconducting wire from the source reel onto the first lane of the first bobbin a first number of times in a first direction; fixing the first bobbin and the second bobbin to each other; winding the superconducting wire from the source reel onto the third lane of the second bobbin a second number of times in the first direction; separating the first bobbin and the second bobbin from each other; and winding the superconducting wire from the first lane of the first bobbin onto the fourth lane of the second bobbin a third number of times in a second direction which is different from the first direction while winding the superconducting wire from the third lane of the second bobbin onto the source reel the third number of times in the second direction.

Method of winding superconducting wire and magnet fabricated using the method

A control method of a multi-air conditioner in which a plurality of indoor units is connected to one outdoor unit and refrigerant flow amount is adjusted by electronic expansion valves comprises a share step in which a plurality of indoor units exchanges their operation information, a comparison and judgment step in which each above indoor unit compares and judges its operation status based on the exchanged operation information, and an adjustment step in which each above indoor unit adjusts refrigerant flow amount supplied to each indoor unit based on the compared and judged operation status.

Control method of an air conditioner indoor unit

A method for controlling a multi-unit air conditioner is disclosed which is capable of preventing frost from being formed on the outer surface of a refrigerant line. In order to control an air conditioner including an outdoor unit, a plurality of indoor units corresponding to the out door unit, and a plurality of refrigerant lines for connecting the indoor units to the outdoor unit, respectively, the method includes the steps of measuring respective states of the refrigerant lines using a measurement sensor, determining respective states of the refrigerant lines, based on measurement data obtained by the measurement sensor, and controlling an operation state of an operating one or operating ones of the indoor units, in accordance with the determined state of the refrigerant line associated with the operating indoor unit or each operating indoor unit.

Method for controlling air conditioner

Growing community of inventors

Seoul, South Korea

Jae Sik Kang