Current limit control method and current limit control device of three-level inverter

A three-level inverter and current-limiting control technology, applied in the electronic field, can solve problems such as positive and negative busbar mutual irrigation, output voltage waveform difference, single-side busbar is large, etc., to prevent overvoltage, good output waveform, avoid Effects of too frequent movements
CN104518697AActive Publication Date: 2015-04-15EMERSON NETWORK POWER CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
EMERSON NETWORK POWER CO LTD
Publication Date
2015-04-15

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Abstract

The invention discloses a current limit control method and a current limit control device of a three-level inverter. The current limit control device comprises a current limit control unit, an auxiliary switching tube switch-on unit and a main switching tube switch-on unit. The current limit control method includes: S1, when currents outputted by a bridge leg are larger than or equal to a current limit threshold value, switching off two main switching tubes and then switching off two auxiliary switching tubes; S2, when the currents outputted by the bridge leg are decreased to be smaller than the current limit threshold value, enabling the two auxiliary switching tubes to act according to normal switching logic; S3, when the currents outputted by the bridge leg are decreased to be smaller than the current limit threshold value and effective edges of PWM (pulse-width modulation) signals of the main switching tubes or auxiliary switching tubes are reached, enabling the two main switching tubes to act according to the normal switching logic. By the current limit control method and the current limit control device, time for mutual energy infusion and mutual charging of positive and negative buses is shortened, overvoltage of the unilateral bus is avoided, frequent actions of the main switching tubes are avoided, the switching tubes are protected, and output voltage waveforms are improved.
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Description

technical field

[0001] The present invention relates to the field of electronic technology, more specifically, to a current limiting control method and device for a three-level inverter. Background technique

[0002] The inverter is an important part of the Uninterruptible Power System (UPS), and its reliability directly determines the stability of the UPS operation. Current limiting technology is a very important protection technology of the inverter, which can effectively protect the power switching elements and improve the impact resistance of the inverter when the inverter is suddenly overloaded or the output is short-circuited. The existing current limiting technology generally detects the inductor current (the current flowing through the power switching element), compares the detected inductor current with the set threshold, and generates a limit when the inductor current exceeds the set threshold. Current protection signal, the power switching element is turned off b...

Claims

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