Magnetic-field shielding efficiency testing method used for small-sized shielding box

A technology of shielding effectiveness and testing methods, applied in the fields of electromagnetic field characteristics, measuring electricity, measuring devices, etc., can solve problems such as lack of solutions, and achieve the effect of good reference value

Inactive Publication Date: 2019-11-12
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There is still a lack of a relatively complete solution for the magnetic field shielding

Method used

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  • Magnetic-field shielding efficiency testing method used for small-sized shielding box
  • Magnetic-field shielding efficiency testing method used for small-sized shielding box
  • Magnetic-field shielding efficiency testing method used for small-sized shielding box

Examples

Experimental program
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Example Embodiment

[0043] Example 1

[0044] The shielding effectiveness test of an existing board shielding box is carried out by adopting the test scheme of the present invention. The specification of the shielding box is 225mm×195mm×40mm (thickness 1mm), and the material is aluminum (conductivity σ=3.7×10 7 S / m, relative permeability μ r =1), wherein, one side has three openings with a size of 26mm×9mm, one side has two openings of 20mm×12mm, and one side has one opening of 24mm×20mm.

[0045] Set the output voltage of the pulsed magnetic field generator to 3.5kV, and the voltage waveform U induced by the probe 0 like figure 2 as shown, image 3 Its corresponding amplitude-frequency characteristic. After installing the shielding box, the probe induced voltage waveform Us is as follows: Figure 4 as shown, Figure 5 Its corresponding amplitude-frequency characteristic. Use Fourier transform to analyze the two time-domain waveforms into the DC-1MHz frequency domain, calculate the shiel...

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Abstract

The invention discloses a magnetic-field shielding efficiency testing method used for a small-sized shielding box. The method belongs to the field of electromagnetic compatibility. Firstly, a testingplatform is built, and then the built testing platform is used to test magnetic-field shielding efficiency of the small-sized shielding box; and magnetic shielding characteristics of the small-sized shielding box under a large-volume uniform magnetic field can be well obtained through the testing platform. The method has a good reference value for evaluating a situation of harassing a circuit board in the shielding box by the spatial magnetic field.

Description

technical field [0001] The invention belongs to the field of electromagnetic compatibility, in particular to a method for testing the magnetic field shielding effectiveness of a small-sized shielding box. Background technique [0002] With the development of flexible straight technology, the application of DC circuit breakers is increasing, and the voltage level is getting higher and higher. During the breaking process of the DC circuit breaker, the sharp change of voltage and current will generate a high-intensity transient electromagnetic field inside and near the valve tower of the circuit breaker, which will further affect the secondary boards such as the IGBT drive and control circuits arranged on the valve tower. The card generates space electromagnetic disturbance. The frequency of the magnetic field in the valve tower is mainly concentrated below 1MHz, and the distribution of the magnetic field in the tower is relatively uniform. In actual engineering, the board is ...

Claims

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Application Information

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IPC IPC(8): G01R29/08G01R31/00
CPCG01R29/0835G01R31/001
Inventor 焦重庆李天乐白婉欣郭安琪
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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