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Control of mmc during fault

A technology of fault and control device, applied in the direction of output power conversion device, transportation and packaging, AC network circuit, etc., can solve the problems of power transmission interruption, tripping of the main circuit breaker of the converter, etc.

Active Publication Date: 2020-02-18
HITACHI ENERGY SWITZERLAND AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This could cause the converter main circuit breaker to trip, resulting in interruption of power transfer, which is not desired

Method used

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  • Control of mmc during fault
  • Control of mmc during fault
  • Control of mmc during fault

Examples

Experimental program
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Embodiment Construction

[0019] Embodiments will now be described more fully hereinafter with reference to the accompanying drawings in which certain embodiments are shown. However, other embodiments in many different forms are possible within the scope of this disclosure. Rather, the following embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Throughout the specification, like numbers refer to like elements.

[0020] The following description focuses on railway interlocking power grid MMC (3-phase to 1-phase direct converter) (see figure 1 ), but embodiments of the invention can be easily applied to other topologies, such as for example:

[0021] · Statcom in MMC delta topology (see figure 2 ).

[0022] • Statcom in MMC star and / or dual star topology.

[0023] • 3-phase to 3-phase MMCs in direct and / or indirect topologies (eg for pumped hydro power plant applications). ...

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PUM

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Abstract

The present disclosure relates to a method of controlling a Modular Multilevel Converter (MMC) (1) during a fault in a power grid (5) to which the MMC is connected. The MMC comprises a plurality of phases (2), each comprising at least one phase leg (3). Each phase leg comprises a plurality of series connected converter cells (4). The method comprises determining that a fault has occurred in the power grid, said fault including a reduced voltage in the power grid. The method also comprises, for each phase leg of the MMC, reducing the DC voltage of the phase leg by a predetermined amount from anominal DC voltage to a reduced DC voltage, the DC voltage being the sum of all respective voltages over an energy storage of each cell of the phase leg. The method also comprises determining that thefault has been cleared, whereby the voltage in the power grid is returned to nominal. The method also comprises for each of the phase legs of the MMC, increasing the DC voltage back to the nominal DCvoltage.

Description

technical field [0001] The present disclosure relates to controlling an MMC during a fault in an electrical grid to which the MMC is connected. Background technique [0002] A Modular Multilevel Converter (MMC) (also known as a Chain Link Converter (CLC)) consists of multiple converter units (also known as converter submodules) that In series connection (cascade, chain link) in converter branches (also called phase legs or phase arms) which can in turn be arranged in star (Y-shape), delta, direct or indirect flow topology. Each converter unit comprises semiconductor switches in topology forming a half-bridge (unipolar) or full-bridge (bipolar, H-bridge) circuit with capacitors for energy storage. Semiconductor switches such as insulated gate bipolar transistor (IGBT) devices, gate turn-off thyristor (GTO) devices, integrated gate commutated thyristor (IGCT) devices, or metal oxide semiconductor field effect transistor (MOSFET) devices can be used to switch Capacitors are ...

Claims

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Application Information

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IPC IPC(8): H02M1/32H02M7/483
CPCH02M1/32H02M7/4835H02J3/00125B60M3/02H02M1/0025
Inventor B·巴克曼C·班凯努
Owner HITACHI ENERGY SWITZERLAND AG