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Asymmetric six-level rectifier and control method thereof

A control method and rectifier technology, which are applied to electrical components, conversion devices for converting AC power input to DC power output, and output power, etc. Simple, scalable and practical effect

Inactive Publication Date: 2022-03-11
SHANDONG LABOR VOCATIONAL & TECHN COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Non-linear circuits such as traditional diode uncontrolled rectification and phase-controlled rectification, because the current waveform on the input side deviates from the sinusoidal curve seriously, will cause the current to contain large harmonic components, reduce the power factor of the rectifier, increase the total harmonic distortion rate of the current, The circuit loss is large, causing harm to the operation safety of the power grid
[0005] Compared with traditional two-level and three-level converters, multilevel rectifiers reduce output voltage jumps, reduce harmonic content and current THD due to increased output levels, and increase the number of levels at the same time, improving The equivalent switching frequency of the power device is improved, and the efficiency is improved; however, the inventors found that the existing multilevel rectifier has the disadvantages of many level shifter switching devices and a complex overall structure

Method used

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  • Asymmetric six-level rectifier and control method thereof
  • Asymmetric six-level rectifier and control method thereof
  • Asymmetric six-level rectifier and control method thereof

Examples

Experimental program
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Embodiment 1

[0039] The purpose of this embodiment is to provide an asymmetric six-level rectifier.

[0040] Such as figure 1 As shown, an asymmetric six-level rectifier includes three-phase bridge arms connected in parallel, and each phase bridge arm includes an H-bridge circuit, a diode and an IGBT tube; the H-bridge circuit outputs three levels, and the diode and the IGBT tube and the The DC side capacitor cooperates to output two levels, and the two parts are cascaded to output six levels;

[0041] The controller of the six-level rectifier determines the six-level space vector diagram based on the pre-built six-level switch state, and realizes the six-level harmonic-free output; at the same time, using the value function constructed based on the space vector diagram, Realize grid-connected current tracking and three-phase floating capacitor voltage equalization.

[0042] Further, each phase of the H-bridge circuit is connected in parallel with a floating capacitor.

[0043] Further,...

Embodiment 2

[0053] The purpose of this embodiment is to provide a control method for an asymmetric six-level rectifier.

[0054] A control method for an asymmetric six-level rectifier, which utilizes the above-mentioned asymmetric six-level rectifier, the control method comprising:

[0055] Obtain the three-phase sampling current, and obtain the current in the two-phase stationary coordinate system through Clark transformation;

[0056] Carry out coordinate transformation on the sampling voltage on the three-phase network side to obtain the voltage value in the two-phase stationary coordinate system;

[0057] Based on the obtained current in the two-phase stationary coordinate system and the Lagrange extrapolation method, the current at the next moment is obtained; and based on the voltage value in the two-phase stationary coordinate system and the discretized predictive control model, the next moment is obtained The reference voltage value of , based on the value function of minimizing ...

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Abstract

The invention provides an asymmetric six-level rectifier and a control method thereof, the asymmetric six-level rectifier comprises three phases of bridge arms which are connected in parallel, and each phase of bridge arm comprises an H bridge circuit, a diode and an IGBT tube; the H-bridge circuit outputs three levels, the diode and the IGBT tube are matched with the direct current side capacitor to output two levels, and six levels are output through cascade connection of the two parts; a controller of the six-level rectifier determines a six-level space vector diagram based on a pre-constructed six-level switch state to realize six-level harmonic-free output; meanwhile, grid-connected current tracking and three-phase suspension capacitor voltage equality are realized by using a value function constructed based on the space vector diagram. According to the scheme, a direct-current side midpoint is not led out, so that a control scheme does not need to be designed to control direct-current side capacitor voltage balance; meanwhile, according to the scheme, only five IGBTs are adopted for each phase, multiple levels are achieved through fewer IGBTs, and cost is saved compared with other multi-level topologies.

Description

technical field [0001] The disclosure belongs to the technical field of rectifier control, and in particular relates to an asymmetric six-level rectifier and a control method thereof. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] As an efficient and convenient energy source, electric energy has been more and more utilized in the modern age of rapid industrial development. However, how to further optimize the power quality and improve the efficiency of power conversion needs to be solved urgently. [0004] Non-linear circuits such as traditional diode uncontrolled rectification and phase-controlled rectification, because the current waveform on the input side deviates from the sinusoidal curve seriously, will cause the current to contain large harmonic components, reduce the power factor of the rectifier, increase the total harmonic dis...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/219H02M1/12
CPCH02M7/219H02M1/12
Inventor 陈华孙宪良刘汉香韩莉娜樊荣莹
Owner SHANDONG LABOR VOCATIONAL & TECHN COLLEGE
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