Bipolar AC-AC converter topology and modulation method

A bipolar and converter technology, applied in the direction of converting AC power input to AC power output, output power conversion devices, electrical components, etc., can solve the problems of low utilization rate of converter modulation ratio, unipolar voltage output, etc. , to achieve the effect of improving conversion efficiency, improving reliability, and reducing the number of power transmission stages

Active Publication Date: 2019-07-12
NORTHEAST DIANLI UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide a bipolar dual-buck type direct AC-AC converter topology, which solves the inherent commutation problem, unipolar voltage output problem and converter of the existing AC-AC converter structure. The problem of low modulation ratio utilization caused by the need to set dead time

Method used

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  • Bipolar AC-AC converter topology and modulation method
  • Bipolar AC-AC converter topology and modulation method
  • Bipolar AC-AC converter topology and modulation method

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Embodiment

[0064] It can be seen from the output of the positive and negative bridge arms of the topology structure of the present invention that there are various schemes for controlling the output bipolar voltage. Here is a special example when d 1 = d 1x , d 2 = d 2x and d 1 >d 2 When , the actions of each switch tube are as follows: image 3 Shown:

[0065] The working principle of the output positive polarity voltage of this structure is analyzed as follows:

[0066] a) When the AC positive half-wave is input, working stage 1: such as Figure 4 As shown, the full-controlled power switch tube T of the positive bridge arm 2 , full-control power switch tube T 2c Normally open, fully controlled power switch tube T 1 Turn-on, full-control power switch tube T 1c Turn off, fully controlled power switch tube T of negative polarity bridge arm 2 , full-control power switch tube T 2c Normally open, fully controlled power switch tube T 1p Turn off, fully controlled power switch tu...

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Abstract

The invention discloses a bipolar AC-AC converter topology structure, which comprises a single-phase system AC power supply, a dual-buck power conversion unit, an LC low-pass filter unit and a signalcontrol unit, wherein the power conversion unit includes a positive-polarity bridge arm and a negative-polarity bridge arm, the output end A of the positive-polarity bridge arm and the output end B ofthe negative-polarity bridge arm are connected with the LC low-pass filter, and the output end of the LC low-pass filter is connected to a load. The converter of the invention can better output voltage with the phase being the same as or opposite to that of input voltage and operate in the same buck/boost operating mode when outputting the voltage with the phase being the same as or opposite to that of the input voltage, so that the converter is enabled to maintain the continuity of the output side current without adopting a high-capacity capacitor. The invention further discloses a modulation method of the structure, which enables the minimum number of switch tubes to perform the high-frequency switching operation within each half period of the input voltage, reduces the total switchingloss and improves the efficiency of the converter.

Description

technical field [0001] The invention belongs to the technical field of electric energy conversion, and specifically relates to a bipolar dual-buck type direct AC-AC converter topology, and also relates to a bipolar dual-buck type direct AC-AC converter topology modulation method. Background technique [0002] Voltage is one of the core indicators of power quality, and its stability plays a vital role in both the safe and stable operation of the power system and the normal operation of user-side electrical equipment. With the continuous increase of the grid-connected capacity of renewable energy represented by distributed photovoltaics and wind power, the power flow of the original power grid is changed, and the reverse flow of the power flow may occur, causing the grid overvoltage problem; in addition, the load The continuous increase is easy to cause the problem of low voltage. With the continuous development of technology, sensitive loads represented by high-precision ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M5/293
CPCH02M5/293H02M5/2932
Inventor 刘闯蔡国伟汪鹏郭东波王艺博
Owner NORTHEAST DIANLI UNIVERSITY
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