uncorrected proof version International Journal of Applied Electromagnetics and Mechanics 1 (2019) s1–s14 s1 DOI 10.3233/JAE-191113 IOS Press Many-objective shape optimisation of IPM motors for electric vehicle traction Paolo Di Barba a , Maria Evelina Mognaschi a , Najmeh Rezaei a, ∗ , David Alister Lowther b and Tanvir Rahman c a Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy b Department of Electrical and Computer Engineering, McGill University, Montreal, Québec, Canada c Mentor Infolytica – A Siemens Business, Montreal, PQ, H2X 2B4, Canada Abstract. The main aim of this work is to determine the optimal shape design of a class of Interior Permanent-Magnet (IPM) motors for electric vehicles (EV), by means of many-objective optimisation which is an emerging area in the automated optimal design. As the case study, a 3-phase, 4-pole single-barrier IPM motor is modelled by means of using finite-element analysis. The goal is to optimise the motor’s performance in terms of a number of design criteria such as the power losses, running torque, torque ripple and material costs, by varying size and position of the permanent magnet and flux barriers. Keywords: Finite-element analysis, interior permanent-magnet motor, many-objective optimisation, optimal shape design 1. Introduction In this paper, strategies for solving many-objective optimisation problems are studied under the framework of a class of motors with applications in electric vehicles. In particular, a shape design of an Interior Permanent Magnet (IPM) motor is considered. Due to their highly salient rotor structure and strong reluctance torque component, IPM motors are commonly characterised by high torque density, high power density and a wide speed range for during constant power operation and high efficiency. Therefore, IPM machines have been considered a good candidate for high-performance traction applications. Extending the constant-power speed range (CPSR) for an EV motor is the key to operating at a wide speed range [1]. In IPM machines, because the permanent magnets are located inside the rotor, the field is directly short-circuited through the rotor iron core that leads to magnetic flux leakage. Therefore, the geometry of the permanent magnet significantly impacts the motor performances, e.g., the cogging torque and the iron losses as well as the constant-power speed range. In order to improve the performances of this kind of motors, many requirements can be demanded. In particular, a lightweight, compact and efficient motor in terms of low iron loss, high running torque but low ripple torque, are only some of the desired design requirements. Hence, the design of such motors is naturally formulated as a many-objective optimisation problem that can be eventually solved by means * Corresponding author: Najmeh Rezaei, Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy. Tel.: +39 0382985785; Fax: +39 0382 422276; E-mail: najmeh.rezaei01@ateneopv.it. 1383-5416/19/$35.00 © 2019 – IOS Press and the authors. All rights reserved