Influence of machine integration on the thermal behavior of a PM drive for hybrid electric traction

We present a method for fast identification of the thermal behavior of vehicle integrated electric drives to propose a better understanding of electric machine design tailored to driving cycles. A simple, but satisfactorily accurate calculation method for the estimation of machine losses, which is an input for the analytic thermal network, in the early design stage is introduced. The analytic models, which are verified using measurement data, are used for parameter and case studies for consideration of the thermal environment with focus on the gearbox. An improvement of machine performance using an alternative cooling approach which cools down the end windings is shown in the final section of the paper.