Why are nanocrystalline soft magnetic materials first choice for EMI in automotive power electronic systems?

Due to a unique combination of excellent soft magnetic properties, nanocrystalline materials became increasingly important in numerous electrical power applications in the last decade. The main reason for that is, that they meet the requirements of todays and tomorrows advanced power electronic systems far better than any other soft magnetic material. Those requirements are: higher efficiency, lighter, smaller and smarter and finally more reliable in high temperature operation. Since many years, nanocrystalline cores and chokes providing EMI and bearing protection in inverter systems for energy conversion, generation, and distribution. The most recent big and dynamically emerging field of application for nanocrystalline inductive components appears to be the upcoming electro mobility. In no other known application than the electrical vehicle PHEV or BEV, such an aggressive source of unwanted high frequency EMI noise like a drive inverter is operating so closely together with an ultra sensitive computer controlled self-driving system. Literally “fire and ice” in a tin can! This extreme scenario asks for solid solutions without any trade-off – in particular, when the next generation of semiconductors GaN and SiC will replace state-of-the-art Silicon devices. For decades in the past, common mode EMI/EMC filter chokes were solely equipped with Ferrite cores. Due to their significantly higher permeability, nanocrystalline filter components reduce weight, size and power loss significantly – typically by 50% compared to Ferrites. Furthermore, nanocrystalline cores withstand much higher working temperatures as they are requested in the automotive application. The lecture will cover a comparison of EMI related soft magnetic properties between nanocrystalline materials and Ferrites as well as some inverter related established application examples and finally come to the concrete fields of application onboard of the electrical vehicles PHEV and BEV.

Autor: Dr. Martin Ferch
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