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Frequency-doubled circulation injection method for suppressing MMC bridge arm power fluctuation under fault

A technology of power fluctuation and frequency doubling, applied in the direction of output power conversion device, AC power input conversion to DC power output, AC network circuit, etc., can solve sub-module capacitor voltage fluctuation, power electronic device damage, device overvoltage And other issues

Active Publication Date: 2021-05-28
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When an AC single-phase ground fault occurs, the dynamic characteristics of the MMC will change greatly, and the voltage fluctuation of the sub-module capacitor will inevitably increase, which may cause device overvoltage and cause damage to power electronic devices

Method used

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  • Frequency-doubled circulation injection method for suppressing MMC bridge arm power fluctuation under fault
  • Frequency-doubled circulation injection method for suppressing MMC bridge arm power fluctuation under fault
  • Frequency-doubled circulation injection method for suppressing MMC bridge arm power fluctuation under fault

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Embodiment Construction

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0015] The embodiment of the present invention provides a double-frequency circulating current injection method that suppresses the power fluctuation of the MMC bridge arm under a fault. The flow chart and the overall system control block diagram are as follows Figure 1 ~ Figure 2 As shown, the method mainly includes the following steps:

[0016] 1. Taking the fundamental frequency and double frequency fluctuation components of the instantaneous p...

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Abstract

The invention discloses a frequency-doubled circulation injection method for suppressing MMC bridge arm power fluctuation under a fault, and the method comprises the steps: taking a fundamental frequency and a frequency-doubled fluctuation component of bridge arm instantaneous power when an AC single-phase fault occurs as suppression targets, and building an optimization target function; carrying out global optimization by taking target function minimization as a target, and obtaining the optimal amplitude and phase of frequency-doubled circulation injection; and generating a reference signal according to the optimal amplitude and phase of the frequency-doubled circulation injection, and realizing the frequency-doubled circulation injection in combination with a modulation algorithm. According to the method, the capacitor voltage fluctuation of the sub-module during the fault period can be effectively reduced, and the maximum voltage borne by the MMC sub-module during the fault period is reduced.

Description

technical field [0001] The invention relates to the technical field of flexible direct current transmission, in particular to a double-frequency circulating current injection method for suppressing power fluctuations of MMC bridge arms under fault conditions. Background technique [0002] Flexible direct current transmission (VSC-HVDC) is a new generation of direct current transmission technology after alternating current and conventional direct current transmission. Flexible DC transmission technology has the characteristics of independent adjustment of active power and reactive power, strong weak grid access and low voltage ride-through capabilities, low AC filtering and reactive power compensation requirements, etc. Modular multilevel converter (MMC) has the characteristics of flexible control, module scalability, low switching frequency, and low harmonic content. At present, the Shanghai Nanhui flexible DC project, the Nanao three-terminal flexible DC project, the Zhous...

Claims

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Application Information

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IPC IPC(8): H02M1/32H02M7/483H02J3/00H02J3/36
CPCH02M1/32H02M7/483H02J3/001H02J3/36H02J2003/365Y02E60/60
Inventor 许建中邓伟成
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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