MMC power module overvoltage protection circuit and multistage bypassing method

A technology of overvoltage protection circuit and power module, which is applied in the field of electric power, can solve problems such as continuous charging of capacitors, and achieve the effect of improving system reliability

Pending Publication Date: 2020-02-21
EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problem that the capacitor of the existing MMC power module may be continuously charged during operation, an embodiment of the present invention provides an MMC power module overvoltage protection circuit and a multi-stage bypass method to prevent the MMC power module capacitor from being continuously charged phenomenon occurs

Method used

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  • MMC power module overvoltage protection circuit and multistage bypassing method
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  • MMC power module overvoltage protection circuit and multistage bypassing method

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Embodiment 1

[0022] The MMC power module overvoltage protection circuit provided in this example mainly includes a bypass switch K and a thyristor T. Wherein, the bypass switch K is connected to both ends of the MMC power module in parallel; when the voltage of the capacitor C of the MMC power module exceeds the set safety value, the bypass switch is closed, so that the MMC power module is bypassed, and the capacitor C stops charging. Thereby, the occurrence of continuous charging of the capacitor C is effectively prevented, and safety is ensured.

[0023] When the bypass switch K cannot be closed in time, since the thyristor T is also connected in parallel to both ends of the MMC power module, when the capacitor C continues to charge, its voltage will continue to rise, once the voltage reaches the breakdown voltage value of the thyristor T When the thyristor is broken down due to overvoltage, a reliable short-circuit path is formed, which makes the MMC power module bypass, and the capacit...

Embodiment 2

[0027] The MMC power module overvoltage multi-stage bypass method provided in this embodiment first connects the bypass switch K and the thyristor T in parallel at both ends of the MMC power module, and then adopts a three-stage bypass method. The software in the board triggers the bypass switch K through calculation, the second-level bypass acts on the bypass switch K from the outlet of the hardware comparison circuit, and the third-level backup bypass adopts hard breakdown thyristors connected in parallel at both ends of the power module, and the gate of the thyristor Extremely short circuit, the primary hardware configuration of the three-stage bypass method see figure 1 or 2 as shown. When the active board fails, the bypass switch refuses to operate, and the capacitor voltage rises to the backup protection value, the bypass thyristors connected in parallel are broken down due to overvoltage, forming a reliable short-circuit path, bypassing the power module, and the remaini...

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Abstract

The invention discloses an MMC power module overvoltage protection circuit and a multistage bypassing method. The circuit comprises a bypass switch connected to the two ends of an MMC power module inparallel and thyristors connected to the two ends of the MMC power module in parallel. When the capacitor voltage of the MMC power module exceeds a set safety value, the bypass switch is closed, so that the MMC power module is bypassed. When the thyristors are broken down due to overvoltage, a reliable short-circuit path is formed, so that the MMC power module is bypassed, and a capacitor of the MMC power module stops charging. The breakdown voltage values of the thyristors are larger than the set safety value and smaller than a rated voltage value of an IGBT of the MMC power module. Accordingto the invention, the bypass switch and the thyristors are arranged for double insurance. When the IGBT of the power module is out of control and the power module is continuously charged, the power module can be reliably bypassed, the IGBT and the capacitor do not explode, other power modules are not influenced, and the continuous operation of an MMC converter valve flexible DC system is not influenced. Therefore, the reliability of the system is improved.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to an MMC power module overvoltage protection circuit and a multi-stage bypass method. Background technique [0002] With the development of high-power flexible DC transmission technology, Modular Multilevel Converter (MMC) is more and more applied to engineering, which has the advantages of low switching frequency, low loss and flexible control. Each bridge arm of this type of converter valve has hundreds of power modules connected in series. Each power module can adopt a full-bridge or half-bridge structure. When the power supply or the main control board fails, the power module becomes uncontrollable. state, the running capacitor will be continuously charged, and the continuous charging current of the capacitor will cause the capacitor voltage to exceed its tolerance range, and eventually the capacitor will undergo insulation breakdown, internal vaporization will cause th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M1/32
CPCH02M1/32H02M1/325
Inventor 邹延生陈晓鹏胡雨龙周竞宇刘坤梁宁国建宝杨光源
Owner EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID
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