Multi-objective Electric Powertrain Design Optimization Under Package Constraints

Abstract:
The design of automotive electric powertrains, comprising electric motors, gearbox, and power electronics, is confined by an assembly space that depends on the entire automotive system. Therefore, the geometric optimization problem of dimensioning and positioning these components has a large number of design variables. These include positions and rotations, but also mechanical parameters such as transmission ratios or bearing dimensions. In this work, an automated design method is presented, based on a division of the problem into a series of sub-problems: the design of the electrical components, the design of the electric motor, gearbox design, positioning of all components within the assembly space, and the generation of the inverter box. The BMW i3 transmission is used as a test case to validate the method, with a simulated reference construction having similar dimensions compared to the original construction. Moreover, the simulation results demonstrate the potential of automated construction by showing a reduction of 55.6 mm in axial length compared to the reference transmission.