VSC control method in three-phase unbalanced state

A technology of balance state and control method, which is applied in the directions of reducing asymmetry of multi-phase network, eliminating/reducing asymmetry of multi-phase network, adjusting/eliminating/compensating reactive power, etc., and can solve problems that limit the normal operation of VSC equipment, etc. Achieve the effects of reducing system loss, increasing device life, and ensuring real-time performance

Active Publication Date: 2020-08-11
SHAANXI UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Existing control methods limit the normal operation of VSC equipment under three-phase unbalanced state to a certain extent

Method used

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  • VSC control method in three-phase unbalanced state
  • VSC control method in three-phase unbalanced state
  • VSC control method in three-phase unbalanced state

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Embodiment Construction

[0039] The present invention is described in further detail below in conjunction with embodiment.

[0040] The present invention controls the VSC device to realize normal power control and unbalance degree compensation under unbalanced state of three-phase load, so as to figure 1 The structure and labels shown in are taken as an example to describe the implementation method of the present invention in detail.

[0041] The control schematic diagram of this method is as follows: figure 2 As shown, it includes a reference value calculation module, a model building and prediction module, and a minimization calculation module. The output control quantity of this control method is a three-way switch signal, corresponding to a three-phase converter.

[0042] The specific detection steps are as follows:

[0043] Step1: Establish a time-domain vector model of the main circuit;

[0044] The VSC structure involved in the present invention, and the principle diagram when accessing the...

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Abstract

The invention discloses a VSC control method in a three-phase unbalanced state. The method comprises the following steps: firstly, establishing a discrete current prediction model in a space vector mode; secondly, calculating a power output predictive quantity; then, calculating complex power needing to be compensated by the system, namely a reference signal; and finally, solving a discrete control signal by utilizing a target function. Separation calculation of positive sequence voltage, negative sequence voltage and current is avoided, phase locking of system voltage is not needed, a vectorcalculation formula derived offline is used for generating reference signals, a vector model is established, discrete control signals are generated through a prediction link, and a modulation link isavoided.

Description

technical field [0001] The invention relates to the technical field of fast compensation control of a voltage source converter (VSC), in particular to a VSC control method in a three-phase unbalanced state. Background technique [0002] In the low-voltage power grid, the unbalanced current between the three phases exists objectively, which has always been one of the main problems that plague the power supply unit. The operation of the low-voltage power grid with a large degree of imbalance will cause adverse effects on the power grid and electrical equipment, such as increasing the power loss of the line and affecting the safe operation of electrical equipment. Therefore, the power electronic devices connected to the low-voltage power grid must have the ability to control under unbalanced conditions, which can meet the normal reactive power compensation, and can also reduce the three-phase current imbalance, so that the power grid can operate normally and safely. [0003] T...

Claims

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Application Information

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IPC IPC(8): H02J3/18H02J3/26
CPCH02J3/1842H02J3/26H02J2203/20Y02E40/30Y02E40/50
Inventor 郭楚佳张芳
Owner SHAANXI UNIV OF SCI & TECH
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