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Method for calculating current reference value of three-phase four-wire grid-connected voltage source type pulse-width modulation (PWM) rectifier

A current reference, voltage source type technology, applied in the direction of converting AC power input to DC power output, electrical components, output power conversion devices, etc., to achieve the effect of high power output

Active Publication Date: 2013-04-03
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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Problems solved by technology

[0005] The purpose of the present invention is to overcome the defects in the power output capability of the current voltage source PWM rectifier used for grid-connected rectification when the voltage unbalanced drop

Method used

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  • Method for calculating current reference value of three-phase four-wire grid-connected voltage source type pulse-width modulation (PWM) rectifier
  • Method for calculating current reference value of three-phase four-wire grid-connected voltage source type pulse-width modulation (PWM) rectifier
  • Method for calculating current reference value of three-phase four-wire grid-connected voltage source type pulse-width modulation (PWM) rectifier

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Embodiment Construction

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0028] figure 1 It is a general topology diagram of a three-phase four-wire PWM rectifier. There are three inductors in series on the three-phase AC side, a capacitor bank on the DC bus, and three bridge arms connected to the AC three-phase. Each bridge arm is composed of two upper and lower switching tubes. ; In addition, there is a neutral line drawn from the midpoint of the DC side. Generally, a filter inductor can be connected in series on the neutral line, and the other end of the neutral line is connected to the grid neutral line when grid-connected. There are many ways to lead out the neutral line from the DC side. Generally, it can be drawn out through the bridge arm composed of the upper and lower switch tubes or from the midpoint of the capacitor bank.

[0029] The present invention is based on the calculation method of the current r...

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Abstract

The invention relates to a method for calculating a current reference value of a three-phase four-wire grid-connected voltage source type PWM rectifier. On the condition of unbalanced drop of grid voltage, the elimination of the active power fluctuation and the suppression of the direct current bus voltage fluctuation serve as the control target. According to the method, on the premise that the requirements of the control target are met, the maximum value in reference values of three-phase current amplitudes can be minimized simultaneously. The method comprises that firstly, three voltage sensors of the rectifier detect to obtain three-phase grid voltage ea, eb and ec, fundamental wave amplitudes Ea, Eb and Ec and fundamental wave phases phi a, phi b and phi c of the three-phase grid voltage can be obtained after processing by three single-phase phase-locked loop structures, and different current reference value calculation methods can be determined according to the criterion that whether the quadratic sum of any two phase amplitudes in grid voltage amplitudes is smaller than the square of the third phase amplitude.

Description

technical field [0001] The invention relates to a method for calculating a current reference value of a three-phase four-wire grid-connected voltage source type PWM rectifier. Background technique [0002] In grid-connected voltage source PWM rectifiers, under the condition of unbalanced grid voltage, the interaction of positive sequence current and negative sequence voltage will produce power fluctuations, and power fluctuations will directly lead to the instability of the DC bus of the rectifier, thereby threatening the stability and stability of the system. Therefore, in order to suppress power fluctuations, additional negative-sequence current needs to be injected, and the coupling term of negative-sequence current and positive-sequence voltage can offset the power fluctuation of the coupling term of positive-sequence current and negative-sequence voltage. [0003] At present, the grid-connected PWM rectifier generally adopts a three-wire system, but for the three-wire r...

Claims

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Application Information

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IPC IPC(8): H02M7/217H02M1/12
Inventor 朱琼锋胡书举付勋波赵斌许洪华
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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