Filter Attenuation Measurement Method Using Electrical Fast Transient Burst (EFTB) [Part 2 of 3]

In our previous blog post, we introduced a project we started in order to offer our customers more information on electrical fast transient burst (EFTB) attenuation.

In this post, we're diving deeper into this collaborative effort between Rich Spangenberg from Schneider Electric and Jared Quenzer from Wurth Electronics by explaining their measurement methodology and the challenges they faced.

If you’ll be attending APEC 2019 in Anaheim, California, you can learn even more about this topic by attending Jared’s session on Thursday, March 21, at 1:45PM in room 213B or by stopping by our booth to ask us questions about filter attenuation using EFTB (or anything else!).

Measurement Methodology

To start developing the new measurement method, Rich and Jared basically decided to start with standard EMC lab equipment: EFTB generator and coupler, oscilloscope and spectrum analyzer. Then they would simply connect a common mode choke directly to the EFTB generator and measure the output directly on the spectrum analyzer, right? Wrong, it was not that simple!

Since the test requirements of IEC 61000-4-4 are intended for system-level testing of a final product, they had to develop their own test method to be able to test on the component level.

Some of the primary requirements for the fixture were:

  • 50 ohm load
  • Stepping down 4kV signal with good signal integrity
  • Low impedance ground plane for return current
  • Easily switch from differential mode to common mode configurations

Challenges & Lessons Learned

While they were developing their test method, they encountered some challenges:

  • How to setup the spectrum analyzer to achieve consistent data from testing one sample compared to the next. This required, optimizing the spectrum analyzer settings to balance repeatability with measurement speed.
  • How to ensure the fixture design integrated a low impedance return plane. The return plane that was specified in the standard was not sufficient for a component-level test, therefore they needed to revise the return plane.

These two problems were rather predictable, but a third problem seemed to come out of nowhere and caused a major delay!

Time + Frequency Domain Measurements

Once the fixture was complete and the major challenges were solved, Rich and Jared looked at the time domain using the oscilloscope. A few main points they noticed with the time domain:

  • The CMC caused significant changes to the pulse amplitude and wave shape
  • However, it was difficult to infer frequency behavior from the time domain plot. Everyone knows how much the EMC community loves the frequency domain!

Rich and Jared also wanted to look at both the time domain and the frequency domain together to give a more complete picture of what was happening.

Were there any major surprises in the frequency domain?

Stay Tuned for More!

Check back with our blog to see the final post in this series.

And remember, if you’ll be attending APEC 2019 in Anaheim, California, you can learn even more about this topic by attending Jared’s session on Thursday March 21, at 1:45PM in room 213B or by stopping by our booth to ask us questions about filter attenuation using EFTB (or anything else!).

on which basis we give the reinforced insulation or basic insulation to any component?

-gb

The choice of reinforced or basic insulation on a transformer depends on the safety standard that is chosen by the designer of the of end product. Most (but not all) standards are usually “system” based instead of “component” based. Therefore, an end product can be built with various configurations of “components” that use either basic or reinforced insulation to meet the safety standard requirements for the “system."

If you share with us your location and contact information we would be happy to connect you with a Wurth Electronics representative who can answer your questions in more detail.

-Wurth Electronics

What is your opinion?

Start a discussion on this topic or leave a comment.
We appreciate your input.

Please note: For editorial reasons, your comment will appear on the website with a time delay.

We reserve the right to modify or delete any submitted comments if they do not comply with our guidelines. Please refer to the Blog Rules for further information.

Please read our privacy policy.

*