Magnetics Business & Technology - September/October 2023 - 16

FEATURE ARTICLE
BMW's Most Powerful e-Propulsion Skips Rare-Earth Magnets in the Rotor
No rare-earth magnets in the rotor and double excitation windings in the stator in new EV line from BMW
BMW is introducing its most powerful all-electric models yet,
employing a new propulsion system design that does without
rare-earth magnets in the rotor and doubles the number of excitation
windings in the stator. Producing the highest output ever for
an all-electric car from the BMW Group, the BMW i7 M70 xDrive
marks another milestone for BMW in its electric mobility transformation
becoming the company's third performance model to have an
all-electric drive system as represented in the new BMW 7 Series
range.
The BMW i7 M70 xDrive, with electric power consumption combined
rated at 23.8 - 20.8 kWh/100 km in the WLTP cycle, is the
most powerful model with an all-electric drive system in the overall
BMW Group portfolio and is being launched in the second half of
this year.
Equipped with an electric motor at both the front and rear axle
generating a maximum system output of 485 kW/660 hp and an Mspecific
chassis, the electric vehicle delivers a new combination of
electric mobility and performance in the company's luxury segment.
The range-topping model of the new BMW 7 Series line-up accelerates
from 0 to 100 km/h (62 mph) in 3.7 seconds, making it the
fastest all-electric BMW model. Top speed is electronically limited
to 250 km/h (155 mph).
It is being built at the company's plant in Dingolfing, Germany
together with all other model variants of the luxury sedan. As well
as being the lead plant for luxury models, the production facility in
Lower Bavaria is also home to the company's competence center
for electric drive system production, which manufactures both the
electric motors and the high-voltage batteries for all variants of the
BMW i7 on site.
16 Magnetics Business & Technology * September/October 2023
BMW 7 Series production at Dingolfing plant
The fifth-generation BMW eDrive technology installed in the BMW
i7 is being constantly developed in order to further improve both
power output and efficiency. This applies not only to the powertrain
and power electronics, but also to the high-voltage battery and
charging technology. It is equipped with highly integrated drive units
at the front and rear axles, bringing together the electric motor,
power electronics and transmission within a single, very compact
housing. The two motors work according to the principle of an
electrically excited synchronous motor. This type of design makes
it possible to completely avoid the use of rare earth metals that are
typically required for magnetic components in the manufacture of
the rotor, notes the company.
An M-specific configuration of the drive system enables the BMW
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Magnetics Business & Technology - September/October 2023

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