The roads of the future are electric: EMC considerations for EV charging points

Author : Holger Urban | Head of Product Management | Schaffner

01 April 2021

Schaffner EV EMC
Schaffner EV EMC

New electric vehicle (EV) models are being introduced almost daily & the market forecast for BEVs (battery electric vehicles) predicts very strong growth over coming years. In 2018, market share of EVs reached approximately 2.5% & the number of EVs built worldwide rose to more than two million units for the first time.

The full version of this article was originally featured in the April 2021 issue of EPDT magazine [read the digital issue]. Sign up to receive your own copy each month.

By 2030, this is expected to increase more than tenfold, which will correspond to twenty million cars sold per year worldwide. And it’s notable that around 80% of EV sales today are for purely electric vehicles (BEVs), as opposed to hybrid. However, as Holger Urban, Head of Product Management at EMC & power electronics specialist, Schaffner  explains here, questions still remain around charging infrastructure…

The charging infrastructure for EVs currently appears to be receiving little consideration in the rush to design, develop, release, market and sell new electric car models. However, in order to successfully implement the eMobility rollout in prospect, this is at least as important as the cars themselves.

According to Bundesverband freier Tankstellen (the German Federal Association of Independent Petrol Stations), approximately 77,000 charging stations will be required for 1 million electric vehicles, including 7,000 DC rapid charging stations. With 20 million cars sold per year, 140,000 DC fast charging stations would have to be installed by 2030. This is a challenge not only from an economic, but also from a technical point of view. Electromagnetic compatibility (EMC) plays a key role in products designed for charging BEV (battery electric vehicles) and HEV (hybrid electric vehicles).

What is electromagnetic compatibility?
Electromagnetic compatibility (EMC) is concerned with the emission and immunity of products connected to the mains supply. The emitted interference or emission generated by lossy switching operations must not exceed specified limits. If non-compliant products are brought  onto the market, problems may arise in operation for other consumers connected to the main power grid. Immunity to interference describes the ability of products to withstand external influences without error. The immunity of products can be verified by various tests, for example by means of the surge, burst or flicker test.

EMC filters, as developed by Schaffner, are available to enable compliance with emission limit standards. These filters are designed to operate in the frequency range between 9 kHz and 30 MHz, in order to suppress conducted interference. This prevents other devices in the environment from being negatively affected. All standard filters are designed in accordance with the IEC 60939-3 standard (‘passive filter units for electromagnetic interference suppression’), and other international standards, and are therefore readily available for use in a potential customer system.

In the case of EV charging stations, electromagnetic compatibility is particularly important, because, without filters, any interference that occurs during rectification in charging stations operated directly from a low-voltage network on the input side could have an effect on the entire network. On the output side, in other words, on the side where the car is charged, the safety of the operator and the interoperability between different charging stations and car manufacturers are of primary importance. Both factors must therefore also be taken into account in the design of the EMC filters...

Read the full article in EPDT's April 2021 issue...

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