MMC sub module with direct-current fault blocking capability

A technology of DC faults and sub-modules, applied in the direction of conversion equipment without intermediate conversion to AC, power transmission AC network, output power conversion device, etc., can solve the large difference in blocking ability, increase the complexity of control and voltage equalization , restrictions and other issues, to achieve the effect of DC fault isolation, easy integration, and strong performance

Active Publication Date: 2018-07-20
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, patent barriers have limited large-scale engineering applications in my country; at the same time, the two capacitors in the clamping twin sub-module are equivalently connected in parallel when the fault current is in the reverse direction, and are blocked when the two capacitors are equivalently connected in series when the fault current is in the forward direction. The capacity difference is large; and the parallel coupling of two capacitors increases the complexity of control and voltage equalization

Method used

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  • MMC sub module with direct-current fault blocking capability
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  • MMC sub module with direct-current fault blocking capability

Examples

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Embodiment 1

[0031] Figure 4 Shown is Example 1 of the present invention. Such as Figure 4 As shown, this embodiment is a hybrid bridge arm in the three-phase six bridge arms in the topology of the modular multilevel converter, and the bridge arm includes MMC sub-modules G1, G2...Gm, half-bridge MMC sub-module H1 , H2...Hn, and reactor L. The first terminal of the first MMC sub-module G1 is connected to the positive pole of the DC side, the second terminal of the first MMC sub-module G1 is connected to the first terminal of the second MMC sub-module G2, and so on, a total of m MMC sub-modules Connection, the second lead-out end of the mMMC sub-module Gm is connected to the first lead-out end of the first half-bridge MMC sub-module H1, and the second lead-out end of the first half-bridge MMC sub-module G1 is connected to the second half-bridge MMC sub-module G2 The first lead-out end, and so on, a total of n half-bridge MMC sub-modules are connected, n≥3, the second lead-out end of the...

Embodiment 2

[0034] Figure 5 Shown is Example 2 of the present invention. Such as Figure 5As shown, this embodiment is a phase mixed bridge arm in the three-phase six bridge arms in the MMC topology, including the first MMC sub-modules G11, G12...G1m, the second MMC sub-modules G21, G22...G2m, the first MMC sub-modules G21, G22...G2m, Half-bridge MMC sub-modules H11, H12...H1n, second half-bridge MMC sub-modules H21, H22...H2n, first reactor L1, second reactor L2, third reactor L3, and fourth reactor L4. The first terminal of the first MMC sub-module G11 is connected to the positive pole of the DC side, the second terminal of the first MMC sub-module G11 is connected to the first terminal of the first MMC sub-module G12, and so on, there are m MMC sub-modules in total connection, m≥3. The second lead-out end of the first MMC sub-module G1m is connected to the first lead-out end of the first reactor L1, and the second lead-out end of the first reactor L1 is connected to the first lead...

Embodiment 3

[0037] Figure 6 Shown is Example 3 of the present invention. like Figure 6 As shown, this embodiment is a phase mixed bridge arm in the three-phase six bridge arms in the MMC topology, including the first MMC sub-modules G11, G12...G1m, the second MMC sub-modules G21, G22...G2m, the first MMC sub-modules G21, G22...G2m, Half-bridge MMC sub-modules H11, H12...H1n, second half-bridge MMC sub-modules H21, H22...H2n, first reactor L1, second reactor L2, third reactor L3, and fourth reactor L4.

[0038] The first terminal of the first half-bridge MMC sub-module H11 is connected to the positive pole of the DC side, the second terminal of the first half-bridge MMC sub-module H11 is connected to the first terminal of the first half-bridge MMC sub-module H12, and so on, A total of n half-bridge MMC sub-modules are connected, n≥3. The second lead-out end of the first half-bridge MMC sub-module H1n is connected to the first lead-out end of the first reactor L1, and the second lead-...

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Abstract

Provided in the invention is an MMC sub module with the direct-current fault blocking capability. The MMC sub module comprises a power electronic device and a capacitor. A hybrid bridge arm formed bya plurality of MMC sub modules form a flexible direct-current power transmission converter; and a rectification or inversion function can be realized in normal operation. When a direct-current bus short-circuit fault occurs at a direct-current side of the converter, a power electronic switch is turned off and the capacitor is connected in series to a clamping diode in a reverse direction to realize direct-current bus fault isolation. Therefore, the short-circuit reverse current fault isolation capability of the flexible direct-current power transmission direct-current side based on a damping dual-sub-unit module is improved.

Description

technical field [0001] The invention relates to an MMC sub-module with DC fault blocking capability. Background technique [0002] As a new type of power transmission, flexible DC transmission technology has unique advantages in solving many problems faced by today's power grids compared with traditional AC transmission methods, and has a good development prospect. The modular multilevel converter (MMC) has been widely accepted by the world for its advantages of easy-to-package modular structure, good scalability and AC output voltage harmonic performance, low switching frequency and loss, etc. approval within. The DC fault protection applicable to the DC grid has become one of the key technologies for the development of the DC grid. However, there are still many key technologies to be broken through in the protection principles applicable to the DC grid. The main technical difficulties include accurate identification and rapid isolation of faults. Although the half-bridge...

Claims

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Application Information

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IPC IPC(8): H02M3/07H02H7/26H02J3/36
CPCH02H7/268H02J3/36H02M3/07H02M1/0067Y02E60/60
Inventor 庞玉彬霍群海郭心铭尹靖元朱晋陆翌许烽韦统振
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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