ECE – 590I POWER & ENERGY SYSTEMS SEMINAR
WHEN: Monday, May 1, 2023
WHERE: ECEB 4070, 4:00 – 5:00 p.m.
SPEAKER, Elie Libbos, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign
TITLE: "Design and Control of a Converter-Integrated Variable-Pole Induction Machine Drive for Electric Vehicles"
ABSTRACT: The US Department of Energy targets an 89% reduction in the volume of electric vehicle (EV) drives via the minimization or complete elimination of permanent magnets. Induction machines (IMs) are an attractive magnet-free alternative because of their low costs, high reliability, and ability to withstand high, short-term overloads. Also, IMs can operate at higher temperatures – above 2000 ° C in the rotor with copper cage – than permanent-magnet-based machines without the risk of demagnetization. Because they do not have any physical magnet to constrain their magnetic fields, the pole count may be varied in operations. Such a possibility opens up a new machine and power electronics co-design environment. We propose an approach that uses a converter-integrated variable-pole induction machine (VPIM) drive that consists of stator toroidal windings and an 18-phase SiC-based integrated inverter. Toroidal windings provide advantages for thermal performance over conventional distributed windings due to an increased exposed copper surface area, that results in a higher stator density. Such a configuration improves power sharing among more phases and the resulting variable-pole operations has higher system efficiency, power density and thermal performance. We discuss in detail the power density and thermal benefits achieved by using the toroidally-wound converter-integrated VPIM drive. In order to attain the benefits associated with pole-changing, the magnetic pole count must be reconfigured during its operation. Typically, today’s approaches trade off smoothness of transition against its duration. We propose a new, smooth and rapid pole-changing approach.