93741 - ELECTRIC MOTOR DESIGN M

Learning outcomes

The aims of the Course are to train the students to the specific knowledge regarding the traditional methodologies for the analaysis and the design of the electrical machines. Furthermore, the appropriate use of simulation software and thermal and electromagnetic field analysis will be presented and discussed. Special attention is paid to the design of brushless machines, with reference to different topology employed in the automotive sector for both traction in BEV and in HEV and for auxiliary drives (EPS,HVAC, fans).

Course contents

General consideration on the design of electric motors. Nameplate data and parameters involved in the design of the electric motors.

Electrical Engineering Materials

Conducting materials, Insulating materials, Soft magnetic materials (Laminations, Composites), Permanent magnets.

Losses in electric motor materials and temperature effects.

Cooling of electric motors

Thermal conduction, convection, and radiation. Equivalent thermal networks, temperature rise, types of duties and ratings.

Finite Element Analysis of electric motors

Introduction to the use of Finite Element software for the analysis of electric motor design.

Induction motors

Design equations for a.c. machines. Leakage reactance of a.c windings with coil- and bar-type. Equivalent circuit and parameter calculation of squirrel cage motors.

Design calculations, effects of the parameter design selection. Free and restricted design. Samples of design calculation.

Design validation via analytical and numerical approach.

Brushless rotating machines

Design relationships for surface mounted permanent magnet machines.

Basic design choices, cogging torque reduction, fractional slot windings, demagnetization.

Design validation via analytical and numerical approach, effects of non-linear materials.

Readings/Bibliography

The pdf files of the slides utilized during the lessons are indispensable and sufficient for the preparation for the exam.

To master and deepen the knowledge of electric drives the following books can be taken into consideration:

J. Pyrhonen, T. Jokinen, V. Hrabovcova: Design of Rotating Electrical Machines, John Wiley & Sons, Great Britain.

J. F. Gieras, M. Wing: Permanent Magnet Motor Technology. Marcel Dekker, Inc., New York, Basel.

Teaching methods

The developed exercises present examples of application of the theoretical subjects.

The development of specific arguments is also proposed leading to a final discussion of the produced report.

As concerns the teaching methods of this course unit, all students must attend Module 1, 2 on Health and Safety online.

Assessment methods

The examination consists in the presentation and discussion of a report of design procedures for specific motors, following the methodology studied during the course.

Teaching tools

Overhead projectors, and PC based presentations are employed during lessons.

Office hours

See the website of Giacomo Sala