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MMC Circuit Structure and Design Method Based on Average Model

A circuit structure and model technology, applied in circuit devices, AC network circuits, power transmission AC networks, etc., can solve the problems of complex algorithms, difficult simulation, slow speed, etc., and achieve the effect of improving simulation speed and versatility.

Active Publication Date: 2019-03-12
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is: the existing technology has the disadvantages of difficult simulation, slow speed or complicated algorithm, and needs to be further improved

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  • MMC Circuit Structure and Design Method Based on Average Model
  • MMC Circuit Structure and Design Method Based on Average Model
  • MMC Circuit Structure and Design Method Based on Average Model

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Embodiment Construction

[0025] combine Figure 1 to Figure 4 Describe the technical scheme and technical principle of the present invention. To solve this problem, the applicant has studied a number of prior art. Existing technology 1 proposes a simplified dynamic model, but the entire bridge arm is equivalent as a whole. Although the basic external output characteristics of the converter are retained in the model, it cannot accurately simulate the characteristics of each sub-module of the converter. The influence of the capacitor voltage change of each sub-module on the output voltage of the AC side has not been considered, and the control of the capacitor voltage of each sub-module in the actual circuit cannot be reflected, because the modeling is not accurate enough.

[0026] Existing technology 2 In order to speed up the simulation speed, a general MMC modeling model based on controlled source is proposed. Replace each bridge arm with a controllable voltage source, and measure the bridge arm cu...

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Abstract

The invention discloses an MMC circuit structure based on an average model and a design method. The MMC circuit structure based on the average model comprises a plurality of serially connected SM, wherein each SM includes a controllable voltage source, a controllable current source and a capacitor, the controllable voltage source and the controllable current source are connected in series and then are in parallel connection with the capacitor. Current of the controllable current source is determined by output current of the SM, and voltage of the controllable voltage source is determined by voltages of positive and negative poles of each submodule. The states of each SM are controlled by controlling the duty ratio component of each SM and include a normal state and a removal state. The MMC circuit structure can simulate the voltage fluctuation situation of each submodule in an MMC switch model, gives consideration to the influence on the alternating-current side of the voltage fluctuation and can control the voltage fluctuation of each submodule to be within a reasonable range. The model can simulate the normal states of the submodules and the removed states when faults occur, the generality is good, and the simulation speed is greatly improved.

Description

technical field [0001] The invention relates to the modeling of the MMC circuit structure, in particular to an MMC circuit structure based on an average model. Background technique [0002] In recent years, MMC has been more and more widely used in HVDC transmission systems. Compared with the traditional two-level and three-level VSC-HVDC, MMC can withstand higher voltage through the series connection of sub-modules, and the number of output levels can increase with the increase of the number of sub-modules, making the output waveform smoother . [0003] In the HVDC power transmission system, there are many sub-modules in each bridge arm of the MMC, the number reaches hundreds, and it needs to be simulated before the actual application, so that reasonable control parameters can be obtained. However, it becomes very difficult and slow to simulate the converter with thousands of sub-modules under the traditional simulation platform. Contents of the invention [0004] The ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/36
CPCH02J3/36H02J2203/20Y02E60/60
Inventor 骆芳芳王建华季振东张金望
Owner SOUTHEAST UNIV