A flexible DC current control method and device

A flexible DC and current control technology, applied in emergency protection circuit devices, output power conversion devices, AC power input conversion to DC power output, etc., can solve problems that affect the stable operation of the system

Active Publication Date: 2021-02-09
ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In the overhead line flexible DC current control technology, if all MMCs use half-bridge power modules, after the overhead line fails, the voltage source converter needs to be blocked, the DC system should be shut down, and the system should be restarted after the fault is cleared. Affect the stable operation of the system

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  • A flexible DC current control method and device
  • A flexible DC current control method and device
  • A flexible DC current control method and device

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Embodiment Construction

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0042] It is worth noting that the flexible DC current control method described in the embodiment of the present invention is applicable to a flexible DC power transmission system. During normal operation, the station-level control method of the flexible DC converter usually adopts direct current control, including two parts: inner loop current control and outer loop voltage control. The outer loop control of the converter station at the sending / receiving end usual...

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Abstract

The invention discloses a flexible DC current control method, which is suitable for a flexible DC power transmission system. The method includes: when a DC grounding fault occurs on an overhead line in the flexible DC power transmission system, collecting the direct current of the flexible DC power transmission system current; inputting the DC current and the preset target value into the PI controller to generate a target voltage; adding the target voltage to the modulated wave reference voltage of the bridge arm of the modular multilevel converter respectively; according to The bridge arm modulated wave reference voltage generates a trigger signal of each power module in the modular multilevel converter to control the DC voltage output of the modular multilevel converter. The invention also discloses a flexible direct current control device. By adopting the embodiments of the present invention, it can effectively ensure that after a DC fault occurs in an overhead line in a flexible DC power transmission system, the DC system will not be blocked or shut down, and the power transmission capability can be quickly restored.

Description

technical field [0001] The invention relates to flexible direct current control technology, in particular to a flexible direct current control method and device. Background technique [0002] MMC (Modular Multilevel Converter) adopts sub-module cascading to construct the converter valve, which avoids the direct series connection of a large number of devices and reduces the requirement for device consistency. Compared with traditional two-level and three-level converters, MMC has the advantages of low manufacturing difficulty, low loss, low step voltage, high waveform quality, and strong fault handling capability. It has been used in flexible direct current transmission and static synchronous compensators has been widely applied. [0003] In the overhead line flexible DC current control technology, if all MMCs use half-bridge power modules, after the overhead line fails, the voltage source converter needs to be blocked, the DC system should be shut down, and the system shoul...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/483H02M7/5387H02H7/26H02J3/36
CPCH02H7/268H02J3/36H02M7/483H02M7/53871H02M7/4835Y02E60/60
Inventor 杨柳黄伟煌朱喆周月宾许树楷
Owner ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD
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