| PhD Seminar

Name of the Speaker: Mr. Kunal Layek (EE19D411)
Guide: Dr. Kamalesh Hatua
Online meeting link: https://meet.google.com/vhs-ffjo-eut
Date/Time: 14th October 2024 (Monday), 2:00 PM
Title: Wide Speed Range Operation of Multiphase Permanent Magnet Synchronous Motors for Electric Vehicles

Abstract :

In the last few decades, Interior Permanent Magnet Synchronous Motors (IPMSM) have garnered wide acceptance as Electric Vehicle (EV) propulsion systems owing to their high torque density, high power density, and high efficiency. Since reliability and fault tolerance are a major concern in EVs, multi-phase PMSMs have been gaining popularity. While multiphase PMSM offers advantages that suit EV requirements, the speed range remains a concern, as at high speeds, a large back-emf is induced in the winding terminals, and hence, a high input voltage is demanded for the motor operation in these conditions. While Field Weakening (FW) is conventionally used to obtain a larger speed range, the efficiency at high speeds is compromised using this technique. A recent approach is to use winding change-over-based techniques, which provide a wider speed range with greater high-speed efficiency. In this seminar, three such winding change-over techniques will be discussed. These techniques differ from each other in their winding configurations and applications.

Among these techniques, a modified tapped winding IPMSM topology is proposed for medium-duty delivery truck applications intended for city traffic. The application of this topology is proven typically reduce the power rating of the power electronic converters by 10%, when compared with FW based techniques. The high-speed efficiency is also improved by 30% for similar applications.

Further, a Split-Tapped IPMSM topology is proposed, which is used for vehicles that require a 3-speed mechanical transmission. The objective of this topology is to emulate the effect of a mechanical gear with the help of bidirectional switches so that the overall drive becomes efficient and high-speed operation is obtained. The proposed split-tapped topology also has the ability to reduce the DC bus (battery) voltage rating by up to 26%, when compared with conventional tapped winding IPMSMs.

Finally, a Dual Three Phase PM assisted Synchronous Reluctance Motor (DTP PMaSynRM) is presented, which can provide 2-speed torque characteristics without any additional switch requirement. A detailed modeling and control technique of this novel topology of the motor will be discussed.

In this seminar, the proposed concepts will be discussed, and suitable results will be presented that validate the applicability of these topologies in EV applications.