Three-level four-leg active filter compensation distribution network neutral current control method

A neutral line current, source filter technology, applied in harmonic reduction devices, AC networks to reduce harmonics/ripples, etc., can solve neutral line overcurrent, fast control system response, unbalanced load, etc. problems, to achieve the effect of improving reliability and realizing fast current tracking control

Active Publication Date: 2014-12-17
STATE GRID CORP OF CHINA +1
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Problems solved by technology

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a control method for compensating the neutral line current of the distribution network with a three-level four-arm active filter, which can effectively solve the problem caused by the unbalanced load in the three-phase four-wire system Neutral line overcurrent and other problems, the control system responds quickly, can realize dynamic real-time compensation, and the control effect is excellent

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  • Three-level four-leg active filter compensation distribution network neutral current control method

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[0029] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0030] like figure 1 , the present invention provides a control method for compensating the neutral wire current of a distribution network with a three-level four-arm active filter, and the control method includes the following steps:

[0031] Step 1: The DC voltage stabilization control module outputs the DC side voltage regulation signal Δi d , superimposed on the instantaneous active current DC component of the compensation current extraction module , to complete the stable control of the DC side voltage;

[0032] Step 2: The DC side voltage balance control module outputs the DC side capacitor balance adjustment signal Δi d * , superimposed on the three-phase voltage signal V output by the current inner loop control module a_ref , V b_ref , V c_ref On, get the three-phase modulation signal V aref , V bref , V cref , to complete the balanced cont...

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Abstract

The invention provides a three-level four-leg active filter compensation distribution network neutral current control method. The method includes the steps of extracting harmonic waves and the sum of negative sequence components and zero sequence components of a line current as a command current of the controlling; setting the alternating current side three-phase current of an active filter and a neutral current as feedback currents, and performing feedforward decoupling control and dq0-abc conversion on each current component of dq0 axis for outputting three-phase voltage after respectively performing abc-dq0 conversion on the command current and the feedback currents; separately performing compensation control on the neutral current. The purpose of direct current side voltage balance and stability can be achieved through direct current side voltage stability and balance control. The three-level four-leg active filter compensation distribution network neutral current control method can effectively solve the problems such as overcurrent of a neutral line due to load imbalance in a three-phase four-wire system and is quick in response of a control system, capable of achieving dynamic real-time compensation and good in control effects.

Description

technical field [0001] The invention relates to a control method, in particular to a control method for compensating the neutral wire current of a distribution network by a three-level four-bridge arm active filter. Background technique [0002] In China's low-voltage distribution network, most of the power is supplied to users with a three-phase four-wire system. If the high-power single-phase load is unbalanced connected to the three-phase grid or the power consumption of the single-phase load is not synchronized, these will lead to three-phase faults in the distribution network. unbalanced. At the same time, it will also bring a series of hazards, for example, the excessive current of the neutral line will cause the line to burn out, the generated zero-sequence current will cause losses to the transformer, and the power supply quality problems such as three-phase voltage asymmetry. [0003] To solve the above-mentioned problems such as excessive neutral line current caus...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/01
CPCY02E40/40
Inventor 祁欢欢赵波
Owner STATE GRID CORP OF CHINA
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