Product Description

EC 62153-4-6,LV 215-2Test system for shielding effectiveness of electric vehicle cable by three coaxial injection method

Two methods to detect the shielding performance of the coaxial cable

In the signal transmission,

Unshielded cables Compared to shielded cables,

More vulnerable to electromagnetic interference,

Thus to communication failure,

Noise becomes larger, signal error and other phenomena.

Upon obtaining the coaxial cable,

How do we detect the shielding performance here?

Along with the widespread use of electric power and electromagnetic waves,

The electromagnetic environment is becoming increasingly complex.

Cable, used as the main connection carrier,

Its shielding efficiency attracts much attention.

For the electromagnetic compatibility requirements of the interface cables in the military backup system,

Design and produce a set of devices using a vector network analyzer

As the signal source and receiver to achieve the coaxial cable

Test device for transfer impedance testing,

The test results were also analyzed and explained.

The transfer impedance is generated by signal induction on the shielding layer,

A common parameter that can reflect the cable shielding performance.

Its good or bad has a lot to do with the shielding layer parameters.

1. Using the spectrum analyzer plus the three-way coaxial method

Any spectrum analyzer should characterize a single root very well

Relative shielding performance of the coaxial cable,

However, with the different spectrum analyzers,

Its constant frequency setting,

The resolution width is different,

The relative shielding performance of the coaxial cable is different.

Using a standard spectrum analyzer to measure the relative shielding performance of the coaxial cable,

The start and termination frequencies can be set to 2.4GHz and 2.5GHz, respectively,

Set the resolution bandwidth to 100kHz,

And adjust the attenuation and reference levels,

While being effectively displayed,

Technically, cables with excellent shielding performance will show very little response.

2. Line injection method

With a wire, namely, the injection line,

Instead of the coaxial good conductor in the three-coaxial method.

Apply a known current and voltage to the shield layer of the cable under test,

Also test the induced voltage between the cable core and the shield layer,

Combined with the equivalent circuit diagram of the line injection method,

The transfer impedance and shielding performance of the tested cables can also be calculated.

Different methods are used to measure the shielding efficiency of the high-voltage shielding cables.

By comparing the results of the different methods,

The characteristics of the different test methods can be obtained.

Studies have shown that the influence of different methods on the results is mainly closely related to the frequency of attention.

With the development of electric vehicles,

A large number of electrical and electronic devices are used,

This makes the electromagnetic environment in the car become more and more complex.

Using shielded cables to reduce RF electromagnetic emission of devices,

And improve the electromagnetic anti-interference ability of related devices.

For high-voltage devices, such as power batteries,

Motor controller and vehicle charger,

Connect with a shielded cable.

besides,

With the development of intelligent connectivity of electric vehicles,

More and more high-speed digital systems are being used in cars,

Transmission lines for high-speed digital systems also use a shielded wire harness.

The test method of automobile shielding wire harness shielding efficiency includes line injection method and three-axis method.

The shielding effectiveness is usually defined by the electrical length of the cable,

The surface transfer impedance reflects the shielding efficacy of the electroshort time,

The shield attenuation indicates the shielding efficiency at electrical length.

When using the line injection method,

Ininjection line can be attached to different locations on the surface of the cable,

If the cable shield is uniform,

The test results at different locations should be consistent.

The line injection method can be tested at both the distal and proximal ends,

Matching circuits can also be used.

Besides the line injection method,

The triple-coaxial method can also be used as a shielding efficacy test.

When using the triple-coaxial method,

Matching circuits can be used,

Damper resistance or terminal matching resistance.

All of these factors may have implications on trial results,

Automobile cable testing related standards

IEC62153-4-1

IEC62153-4-3

IEC62153-4-4

IEC62153-4-7

IEC62153-4-9

IEC62153-4-10

IEC62153-4-15

IEC62153-4-16

EN50289-1-6