A Model-Based Comparison Between Slotted and Slotless Permanent Magnet Motor Topologies by Nicolas VERBEEK

For the degree of Doctor of Engineering Sciences and Technology

High-performance micromotors are becoming ubiquitous through a wide variety of applications that require both high power density and high efficiency. Examples include reaction wheels for the precise positioning of satellites, active prostheses, and surgical power tools. Electric motors that use permanent magnets (PM) typically provide the highest power density and efficiency and are therefore best suited for these applications. These PM motors can be classified based on their stator topology, in either the slotted or slotless topology. Furthermore, various winding variants exist, especially within the slotless topology. One particular slotless winding variant is the use of flexible printed circuits for replacing the traditional round copper wire, offering significant gains in performance. Depending on the application, one choice of topology and winding might be better suited than the other. However, there exists no rigorous comparative study and as a result, the choice is usually made on a case-by-case basis, without proper knowledge of the optimal selection.

Consequently, the main objective of this thesis is to rigorously and systematically compare the slotted and slotless PM topologies and their winding variants based on power density and efficiency, for a wide range of applications and operating conditions. To fulfill this objective and rightfully compare the different motor variants, they need to be extensively described, accurately modeled, and properly optimized to reach the highest possible performance. Performance maps are generated and used to visually compare the different motor variants based on their operating conditions. Finally, these maps are exploited and validated on a particular cycle-based motor application, namely an active ankle prosthesis.

Jury members :

• Prof. Bruno Dehez (UCLouvain, Belgium), supervisor
• Prof. Hervé Jeanmart (UCLouvain, Belgium), chairperson
• Dr. François Baudart (Mirmex Motor, Belgium)
• Prof. Renaud Ronsse (UCLouvain, Belgium)
• Prof. Alexander Badri-Sprowitz (KU Leuven, Belgium)
• Prof. Elena Lomonova (TU Eindhoven, The Netherlands)

Visio conference link : https://teams.microsoft.com/l/meetup-join/19%3ameeting_ZDBjMzhiNzUtNTNmYi00YTk3LWJmMDUtMDc1OTM5YjkzNWY3%40thread.v2/0?context=%7b%22Tid%22%3a%227ab090d4-fa2e-4ecf-bc7c-4127b4d582ec%22%2c%22Oid%22%3a%22b9d473c9-2e60-4c18-8c60-eefba6636e37%22%7d