Series concept of an externally excited synchronous machine as a magnet-free variant to the EMR4 platform

Authors

G. Muehlberg, N. Daun, H. Hakvoort - Vitesco Technologies

Summary

Electromobility is now firmly set to become the mainstream of future mobility. The growing range of Battery Electric Vehicles (BEVs) adds more frequent long-distance high-way trips at higher speeds to the powertrain requirement list. This, together with geopolitical tensions, out-of-sync supply chains, a significantly increased rare-earth cost level and the growing importance of a BEV's Global Warming Potential (GWP) has initiated a comeback of Externally Excited Synchronous Machines (EESM) for BEV powertrains. They offer a rare earth-free alternative to the Permanent Magnet Synchronous Machines (PSMs), which have become the mainstream over the past decade. Considering the growing importance of high-speed driving, EESMs offer a better efficiency at >110 km/h than PSM, and they have a lower overall GWP. Up until recently, EESMs were often seen critically as they can add manufacturing complexity and production cost. Vitesco Technologies has ten years of field-experience with EESM in series use since 2011 and has utilized this expertise to develop a new 400 V/800 V EESM series concept complete with excitation stage that combines the advantages of EESM technology with a significantly simplified and cost-optimized design for manufacturing. The magnet-free EESM rotor is readied as a new option within the modular and scalable EMR4 platform that is compact enough to address even the D-segment, but can be scaled upwards to include all passenger cars segments above.