The challenges of EMC in the all-electric society


Date: 29-08-2023

As we move towards an all-electric and connected society, the interference from electro-magnetic (EM) waves is expected to grow extensively. Updates of the current EMC standards are required to limit these disturbances, yet not all stakeholders agree on how these should be adjusted. CISPR Chair Bettina Funk is working to make all of them aware of necessary changes.

Can you tell us a little about your background?

As my family name indicates, “Funk” meaning “radio” in English, I was predestined to be a radio engineer! I studied electrotechnology at university, specializing in radio and communications technology. My mother was already an electrotechnical engineer, so I had a great role model to follow, and I obtained my degree diploma when I was 23. Studying electrotechnology was a no-brainer for me, but I realize that this is still quite an unusual situation. I then worked in industry before joining the Frequency Regulation Agency in Germany which gave me regulatory experience, linked to the International Telecommunication Union (ITU). Within the Agency, I then switched to standardization for radio technology, taking part in the telecoms standardization body, ETSI. Colleagues at the Swedish regulation agency asked me if I wouldn’t want to move to Sweden and work for them, which I did eight years ago. The job included EMC standardization which led me to attend CISPR meetings. On my very first meeting, the Secretary of CISPR asked me If I would possibly be open to being a candidate for the position of CISPR Chair. He had heard about the work I had done in ETSI, had met me in a previous European meeting and thought that I would be a good candidate. I also had both regulatory and industry experience which was ideal. My manager encouraged me to go and fill that position, a good example of women empowering women! I left the Swedish regulation authority in 2018 and joined SEK, where I am now.

How would you describe your role as Chair of CISPR?

I am essentially a facilitator but sometimes have to be a bit more of an enforcer in order to get things done. We are currently facing many challenges, some of which result from the way EMC work is organized in the IEC. CISPR and IEC TC 77 are the two committees in the IEC that specialize in EMC standardization, and the mandatory IEC Guide 107 tells all the other IEC committees how to use our results in their work. Within CISPR, we have six quite independent subcommittees (SCs). CISPR/A deals with test methods and CISPR/H deals with generic limits and the model to calculate limits, so these two SCs do the horizontal work that is referred to in IEC Guide 107. CISPR/B, D, F and I are dealing with specific product groups or environments and base their work on the results of CISPR/A and CISPR/H. This can lead to conflict when the horizontal SCs either cannot provide methods or models fast enough or when there is disagreement on whether a new method or model is needed and how it should be used.

Any other challenges?

There are so many! One of the most important ones is that we must convince industry stakeholders that we need to adjust the current limits and parameters for EMC. Some of the current limits were agreed upon decades ago and some are no longer fit for purpose as we move towards an all-electric and especially an all-connected society. This is because the electromagnetic environment has changed over time and will continue to change in the future. Before, we simply didn’t have so many electrical products everywhere and some of the protection distances that our current limits are based upon are 10 metres or more, which was adequate in the 1970s.

Just to give you one example of the changing electromagnetic environment; we now have solar panels on roofs mushrooming everywhere, even off-grid, some of which include or are connected to inverters. Those need to be EM compatible with all the other electronic devices that are already on the same roof, sometimes less than a metre away. In the 1970s, we often needed to protect analogue terrestrial TV, while we now have a multitude of radio services on or underneath the roof that need to work without performance degradation.

Many manufacturers see EMC as an extra cost and don’t want to finance the EMC redesign of an existing product, for instance, to ensure that new limits are met. This is why we see a huge reluctance in some industries to accept new work items that could result in lower emission limits in EMC standards. But we need to find a compromise, because our standards otherwise will no longer be used or referred to by regulators. We were not able to publish any update of our most important standards in the last four years because they get voted down at final draft stage. This often happens because the groups that work on the standards take decisions based on majority rule instead of finding compromises. We lack representation from regulators and spectrum users in the working groups and maintenance teams, which can be due to financial reasons or because of a difference in attitude towards standardization. Some spectrum users simply expect that the spectrum is kept clean, because they pay license fees for using it, which is why they do not see any additional need to engage in EMC standardization.

Another challenge is that EM interference is hard to attribute because it can be caused by so many different devices, which some manufacturers take advantage of.

What are the differences between CISPR work and IEC TC 77, which you referred to?

We need to take a trip down memory lane to understand where both are coming from. CISPR was founded in the early 1930s, long before TC 77. In the 1930s, electrification was progressing fast and trams in cities were becoming popular means of transport. Radios were the big broadcasting devices at the time, and people noticed that suddenly things did not work together. You could not listen to your radio because the tram was passing by in the street. And that’s when we started looking at EM emissions. There are two broad areas for EMC work: emissions, i.e. the product emitting EM waves, and immunity, which is the ability of a product to work even though EM waves are in its environment. Emissions can be transported by cables or radiated. When TC 77 was founded inside the IEC, it was mostly involved with the immunity side of things and grid interference, meaning cable-bound emissions. CISPR joined the IEC later and deals mostly with the emissions aspects. As always, reality is a little more complex than this black and white description, but TC 77 and CISPR work together quite closely and will have to more and more, notably as we move towards increasing off-grid electrification.

What will be the focus of CISPR work moving forward?

The focus of our horizontal SCs will be to adapt the test methods and interference calculation model. The test methods for testing frequencies up to and above 40 GHz need to be developed by CISPR/A, because radio services are introduced in higher frequency bands. CISPR/H is cooperating with ITU-R to get input on the latest radio services to be able to use their parameters in the interference calculation model.

One of the main areas on the product side will be wireless power transfer (WPT). CISPR has not yet reached a consensus with the spectrum users on limits for WPT technologies, but other IEC TCs have already included WPT in their standards. We need to make sure that IEC publications are consistent and that the limits in the standards protect radio services, since, in many parts of the world, radio users have priority over electrical systems in the radio spectrum. WPT has a huge potential for disturbing radio services as it is difficult to direct the electric energy in a wireless environment without spilling energy into the spectrum. Electric vehicles are generally a hot topic. We therefore need to adapt EMC standards for vehicles and include new specific parameters for electrical vehicles.

And we don’t even know yet which new radio systems and electric products are waiting for us in the future. The only thing we are sure of is that there will always be more work for us to do since the laws of physics can’t be changed!