Output voltage positive and negative polarity inversion method based on modular multilevel converter

A modular multi-level, output voltage technology, applied in the direction of converting DC power input to DC power output, output power conversion device, and adjusting electrical variables, can solve the problem of not being able to be directly connected, affecting the construction of the high-voltage DC transmission network, etc. problem, achieve the effect of ensuring reliable operation and reducing current impact

Active Publication Date: 2014-12-17
STATE GRID CORP OF CHINA +3
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Problems solved by technology

[0003] HVDC power transmission mainly includes LCC-HVDC and VSC-HVDC; LCC-HVDC adopts thyristor device phase-controlled converter LCC, when the power flow reverses, the voltage polarity is reversed and the current direction remains unchanged, and the voltage source type in VSC-HVDC changes When the power flow of the converter is reversed, the voltage polarity remains unchanged and the current reverses, and VSC-HVDC and LCC-HVDC cannot be directly connected, which affects the construction of HVDC transmission grid

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  • Output voltage positive and negative polarity inversion method based on modular multilevel converter
  • Output voltage positive and negative polarity inversion method based on modular multilevel converter
  • Output voltage positive and negative polarity inversion method based on modular multilevel converter

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Embodiment Construction

[0029] Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0030] The present invention provides a method for inverting the positive and negative polarity of the output voltage based on a modular multilevel converter. By constructing a modular multilevel converter model, the bridge arm voltage is modulated, thereby realizing the positive and negative output voltage of the converter. Polarity reversal; as in figure 1 The modular multilevel converter model shown in the figure includes the VSC side converter and the LCC side converter connected through the isolation transformer; the VSC sid...

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Abstract

The invention provides an output voltage positive and negative polarity inversion method based on a modular multilevel converter. The method includes 1, constructing a modular multilevel converter module; 2, inverting the output voltage positive and negative polarities by adjusting the bridge voltage of the modular multilevel converter module; modulating the upper bridge voltage uu and lower bridge voltage ul of each phase, according to a bridge voltage wave image, into sine wave voltage symmetrical about a horizontal line U = UN/2 vertically, and allowing that the LCC terminal output voltage ULCC = UN; modulating the upper bridge voltage uiu and lower bridge voltage uil of each phase into sine wave voltage symmetrical about a horizontal line U = -UN/2 vertically, and allowing that the LCC terminal output voltage ULCC = -UN. Compared with the prior art, the method has the advantages that the operation requirements of LCC-HVDC and VSC-HVDC interface converters are met, and LCC-HVDC and VSC-HVDC interconnection implementation is benefited.

Description

technical field [0001] The invention relates to a method for reversing the positive and negative polarity of an output voltage, in particular to a method for reversing the positive and negative polarity of an output voltage based on a modular multilevel converter. Background technique [0002] In direct current transmission, extending the point-to-point high-voltage direct current transmission line to multiple terminals and establishing a direct current transmission grid is the key technology to realize large-scale wide-area direct current transmission and distribution; the same as the traditional AC transmission line, the direct current power grid also uses DC-DC converters Realize the interconnection of different HVDC transmission networks. [0003] HVDC power transmission mainly includes LCC-HVDC and VSC-HVDC; LCC-HVDC adopts thyristor device phase-controlled converter LCC, when the power flow reverses, the voltage polarity is reversed and the current direction remains un...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M3/315
Inventor 姚良忠蔡旭朱淼张建文孙长江丁杰杨波许晓慧曹远志卢俊峰李琰陶以彬李官军崔红芬王德顺周晨刘欢鄢盛驰王志冰孙蔚胡金杭冯鑫振吴婧朱红保李跃龙
Owner STATE GRID CORP OF CHINA
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