High Performance Cooling of Traction Brushless Machines
Doktorsavhandling, 2021

The work presented in this thesis covers several aspects of traction electric drive system design. Particular attention is given to the traction electrical machine with focus on the cooling solution, thermal modelling and testing.

A 60 kW peak power traction machine is designed to achieve high power density and high efficiency thanks to direct oil cooling. The machine selected has a tooth coil winding, also defined as non-overlapping fractional slot concentrated winding. This winding concept is state of the art for many applications with high volumes and powers below 10 kW. Also, these have been proven successful in high power applications such as wind power generators. In this thesis, it is shown that this technology is promising also for traction machines and, with some suggested design solutions, can present certain unique advantages when it comes to manufacturing and cooling.

The traction machine in this work is designed for a small two-seater electric vehicle but could as well be used in a parallel hybrid. The proposed solution has the advantage of having a simple winding design and of integrating the cooling within the stator slot and core. A prototype of the machine has been built and tested, showing that the machine can operate with current densities of up to 35 A/mm^2 for 30 seconds and 25 A/mm^2 continuously. This results in a net power density of the built prototype of 24 kW/l and a gross power density of 8 kW/l with a peak efficiency above 94%. It is shown that a version of the same design optimized for mass manufacturing has the potential of having a gross power density of 15.5 kW/l which would be comparable with the best in class traction machines found on the automotive industry.

The cooling solution proposed is resulting in significantly lower winding temperature and an efficiency gain between 1.5% and 3.5% points, depending on the drivecycle, compared to an external jacket cooling, which is a common solution for traction motors.

energy efficiency

electrical machine design

Cooling

drivetrain system analysis.

permanent magnet synchronous machine (PMSM)

Online via Zoom
Opponent: Juha Pyrhönen

Författare

Alessandro Acquaviva

Chalmers, Elektroteknik, Elkraftteknik, Elmaskiner och kraftelektronik

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Styrkeområden

Transport

Ämneskategorier

Elektroteknik och elektronik

Annan elektroteknik och elektronik

ISBN

978-91-7905-433-5

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 0346-718X

Utgivare

Chalmers tekniska högskola

Online via Zoom

Online

Opponent: Juha Pyrhönen

Mer information

Senast uppdaterat

2021-01-25