Cascaded H-bridge type traction network impedance test harmonic generator and test method

A harmonic generator and impedance testing technology, applied in the direction of measuring resistance/reactance/impedance, instruments, measuring devices, etc., can solve the problems of uncontrollable harmonic size, affecting measurement accuracy, blank technical research, etc., and achieve accurate traction network Harmonic impedance characteristics and effects of improved measurement accuracy

Inactive Publication Date: 2016-06-22
BEIJING JIAOTONG UNIV +1
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  • Summary
  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

The capacitor switching method of the intervention method, the harmonics generated during the capacitor switching process are uncontrollable, which affects the measurement accuracy
[0004] At present, there is no special harmonic source generating device that can be used for testing the impedance frequency characteristics of electrified railway traction power supply systems at home and abroad, and the relevant technical research is basically blank.

Method used

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  • Cascaded H-bridge type traction network impedance test harmonic generator and test method
  • Cascaded H-bridge type traction network impedance test harmonic generator and test method

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Embodiment 1: as figure 1 As shown, a cascaded H-bridge type traction network impedance test harmonic generator (referred to as harmonic generator), is composed of the following parts: step-down transformer TP, cascaded converter HG, mining converter reactor Lc . The primary side winding of the step-down transformer TP is connected in series with the traction network, and the secondary-side main winding of the step-down transformer TP is connected to the cascade converter HG through the converter reactor Lc to provide the power supply voltage for the cascade converter HG.

[0025] Such as figure 2 As shown, the cascaded converter HG is composed of power electronic switching devices, which are cascaded with N H-bridge modules, and any two adjacent module units (respectively M m Module and M m+1 Modules) are connected as figure 2 shown. Each module is composed of the first branch arm L1 and the second branch arm L2, such as figure 2 Shown in the red dashed box. ...

Embodiment 2

[0032] Embodiment 2: as figure 1 Shown, a kind of cascaded H-bridge type traction network impedance test harmonic generator test method, contains the following steps;

[0033] Step 1, such as figure 1 As shown, connect this harmonic generator to the traction network. Collect the voltage and current of the primary side of the step-down transformer, the voltage and current of the secondary side, and the output voltage of the cascaded converter port. After the control system, the harmonic generator works in the PWM rectification mode, and the capacitor voltage of each module is stable near the given value. The harmonic generator is not emitting harmonics to the traction network.

[0034]Step 2: Manually input and specify the frequency and amplitude of the harmonic to be emitted, start and issue the harmonic command, and the cascaded converter sends out the specified frequency and amplitude harmonic voltage component through carrier phase shift modulation. This harmonic voltage...

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Abstract

The invention relates to a cascaded H-bridge type traction network impedance test harmonic generator and test method, and belongs to the technical field of electrified railways. A primary side winding of a step-down transformer TP is connected with a traction network, and a secondary side winding is connected with a reactor Lc and a cascaded converter HG to form a loop. The cascaded converter is formed by cascading N (2<=N<=10, N is an integer) single-phase H-bridge modules; and the cascaded converter sends out harmonic voltage with variable amplitude and frequency, the frequency range of the harmonic voltage is 100Hz to 5100Hz, and the amplitude range is 0 to 1000V. Using a simulation modeling method cannot accurately obtain the impedance frequency characteristic and resonant frequency of the traction network, and the cascaded H-bridge type traction network impedance test harmonic generator provides a high-capacity large-voltage broadband harmonic source with adjustable amplitude for actual measurement of the impedance frequency characteristic of the traction network, thereby facilitating improvement of measurement accuracy, and obtaining a more accurate harmonic impedance characteristic of the traction network.

Description

technical field [0001] The invention relates to a cascaded H-bridge type traction network impedance test harmonic generator and a test method, belonging to the technical field of electrified railways. Background technique [0002] With the wide application of high-speed EMUs and high-power electric locomotives in the AC-DC-AC traction transmission mode, the low-order harmonic content in the traction network decreases, but the high-order harmonic content of certain orders may increase. When the high-order harmonic frequency is equal to or close to the resonant frequency of the traction power supply system, and the amplitude exceeds a certain limit, the voltage and current of the harmonic frequency will be amplified, resulting in overvoltage, which is likely to cause catenary (such as lightning arrester) Or substation equipment (such as 27.5kV self-use substation) burnout and power outage accidents will affect the safe and reliable operation of the railway system. Such accide...

Claims

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Application Information

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IPC IPC(8): G01R27/08
CPCG01R27/08
Inventor 吴命利刘秋降杨少兵张洪和吴丽然李静
Owner BEIJING JIAOTONG UNIV
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