The most common type of electric vehicle machine is the permanent magnet synchronous machine (PMSM). Although the use of induction machines does occur, these have comparatively bigger losses and less power density.
However, in Eric Gamez’s and Tapas Sarangi’s master thesis work, induction machines are the study object. In a project funded by Swedish Electromobility Centre, the students model an induction machine to calculate the performance as well as the losses. The student’s work is an important part of the project which is conducted by Torbjörn Thiringer, Professor in Power Engineering Electric at Chalmers University of Technology and his colleagues at KTH Royal Institute of Technology and Lund University.
Investigating how losses occur
In the first step of the master students work, an induction machine has been dismantled in order to conduct the physical measurements that form the basis for the modelling of the machine. The students are now creating mathematical models that accurately reproduce the physical machine, to develop profiles of the losses as well as determining the torque performance of the machine.
“For this specific machine, it is not yet known how and when the losses occur, so this is very interesting to investigate”, says Eric Gamez.
“We hope to produce reliable profiles of how the losses behave under different conditions”, adds Tapas Sarangi.
A more sustainable solution for electric vehicles?
So, if the PMSM machine is reported to be better, why spend time and money investigating the induction machine? Torbjörn Thiringer explains:
“Induction machines are cheaper. In addition, you can avoid certain ecologically hazardous substances that are used in PMSM machines, some of which are produced under ethically untenable conditions. Overall, an induction machine could be a better solution from a life cycle perspective, taking into account efficiency, materials and performance.”
The lab provides an overview of vehicle machines
Not only PMSM and induction machines are analyzed in the lab at the division of Electrical Power Engineering. A wide range of issues regarding the electrical system in electrified vehicles are under investigation here. Right now, room is prepared for an XC90 electric propulsion system from Volvo Car Corporation. The plan is to study the quality of voltage, current, magnetic and electric fields in the high-voltage direct current circuit of the car’s electric power system. The study is performed in cooperation with Volvo Cars.
“Our strategy is to have an overview of different types of vehicle machines and other important electric propulsion components. In our projects, we look to the total energy consumption, which we believe will be of great importance for future vehicle certifications”, concludes Torbjörn Thiringer.
Text and photo: Emilia LundgrenSwedish Electromobility Centre is a national Centre of Excellence for hybrid and electric vehicle technology and charging infrastructure. The Centre unifies Sweden's competence and serve as a base for interaction between academia, industry and society. Chalmers University of Technology is host of the Centre.Partners: AB Volvo, Volvo Car Corporation, Scania CV AB, Autoliv Development AB, Chalmers University of Technology, KTH Royal Institute of Technology, Lund University, Uppsala University, Linköping University.