High Performance Integrated e-Drive

Project Targets

© Fraunhofer IISB

Single wheel traction drive for fully electric vehicles with integrated inverters.

Short Description

A single wheel axle drive unit has been developed that includes two mechanically independent permanent magnet synchronous motors (PMSM) with a reduction gear (7:1). Each motor has a peak-power of 80 kW and a continuous power of 30 kW. The maximum torque per wheel is 2000 Nm. The chosen ‘off-axis’ concept allows a flexible use in a variety of vehicle concepts, for example in small commercial vans, busses or sports cars.

Six ‘Inverter Building Blocks’ are used to realize the double-inverter for the drive unit with a nominal phase current of 350 Arms and a nominal DC link voltage of 400 V. The two independent field-oriented control algorithms are implemented on a central control board with a TriCoreTM processor. Communication to the superior vehicle control system is realized via CAN bus. This allows an independent torque control for each wheel of the axle. An advanced safety architecture is implemented to meet the ASIL-D safety requirements.

The power electronic components including the ‘Inverter Building Blocks’, the controller and the DC busbars are completely integrated into the electric drive. This reduces the required space, the costs and also leads to an improved EMC behavior. A direct connection of the motor AC cables without additional connectors and the common use of one cooling circuit for the two electric machines and the power electronic amongst other things reduce the material and production costs.

Project Partners

SPN Hopf (Gear system, Nördlingen)

Maccon (E-machine, Munich)

Project Duration

2009-2011

Publications

M. Hofmann, A. Schletz, K. Domes, M. März, L. Frey: Modular Inverter Power Electronic for Intelligent e Drives. IEEE-proceedings of Electric Drives Production Conference (EDPC) 2012, Nuremberg, 16/17 October 2012.