Three-phase pulse width modulation rectifying circuit and pre-charging method thereof

Abstract

The invention provides a three-phase pulse width modulation rectifying circuit and a pre-charging method thereof. The three-phase pulse width modulation rectifying circuit comprises a three-phase pulse width modulation rectifier, a first switch, a second switch, a third switch, a first capacitor, a second capacitor, a first one-way charging branch and a second one-way charging branch, wherein thethree-phase pulse width modulation rectifier includes an input end, a positive electrode output terminal and a negative electrode output terminal; the first switch, the second switch and the third switch are connected between the input end of the three-phase pulse width modulation rectifier and an three-phase alternating current; the first capacitor and the second capacitor are connected in seriesbetween the positive electrode output terminal and the negative electrode output terminal, and a node formed by connecting the first capacitor and the second capacitor is connected to a neutral point; the first one-way charging branch is connected between a first-phase alternating current in the three-phase alternating current and the positive electrode output terminal and is used for pre-charging the first capacitor; and the second one-way charging branch is connected between the first-phase alternating current and the negative electrode output terminal and is used for pre-charging the second capacitor. According to the pre-charging method, an input peak current is prevented from being generated.

Description

technical field [0001] The invention relates to a pulse width modulation rectifier circuit, in particular to a three-phase pulse width modulation rectifier circuit and a precharging method thereof. Background technique [0002] The three-phase pulse width modulation rectifier circuit has the advantages of low grid-side current harmonics, high power factor, bidirectional energy flow, etc., and has been widely used and researched. [0003] figure 1 It is a three-phase pulse width modulation rectification circuit in the prior art. Such as figure 1 As shown, the three-phase pulse width modulation rectifier circuit 1 includes a three-phase pulse width modulation rectifier 11; a first switch S11, a second switch S12 and a third switch S13 connected to the input end of the three-phase pulse width modulation rectifier 11; The capacitor C11 of the output terminal of the three-phase pulse width modulation rectifier 11; The capacitor C11 is charged before the switch S11 , the secon...

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Problems solved by technology

[0004] However, the three-phase pulse width modulation rectifier circuit 1 has one or more of the following defects: the circuit structure of the pre-charging circuit 12 is complex, the number of electronic components is large, and the cost is high

Especially when the voltage of a certain phase of alternating current is too large, a very large input peak current or surge current will be generated in the switch and inductance connected in series with the alternating current of this phase, thus causing damage to the switch

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