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Technology Trends in Rotating Machinery
Heeju Choi, Principal Engineer, EEC Motorsolver

The use of permanent magnets (PMs) brings significant advantages to many well-known applications including (hybrid) electric vehicles, motors, generators, electronic devices, etc. The design of the magnetic circuit and the actual magnetic properties of the PMs have a significant impact on the performance of the magnetic systems. This is especially true for most rotatory machines including motors and generators. This presentation will review technology trends in rotary machines and components such as magnetic bearings. In particular, permanent magnets with ultra-high temperature stability enable rotary machines to operate at higher temperatures, with higher efficiencies, power densities and reliability. The talk will also present new magnetic bearing technologies, such as: 1) high temperature magnetic bearings for supercritical-carbon dioxide (S-CO2) turbine machinery, 2) high temperature magnetic couplers for molten salt reactor pumps.  

Heeju Choi is currently a Principal Engineer at EEC Motorsolver, Landisville, PA, USA since 2021. Dr. Choi received the Ph.D. degree in Mechanical Engineering from North Carolina State University, Raleigh, North Carolina, USA, in 2005.  Since 2005, Dr. Choi joined Electron Energy Corporation as a Sr. Applications Engineer.  He is a specialist at rare earth magnet system design using finite element analysis tools (ANSYS Maxwell®, Vector Field Opera®, Solidworks® Simulation). The particular topics of expertise are high temperature motor/generator, high temperature magnetic bearing, high temperature magnetic coupler, eddy current brakes, Halbach array, quadrupole magnets for proton therapy, phase shifter for undulator, mass spectrometer, magnetic separator, high frequency vacuum electronics, ion thruster, traveling wave tube, sheet beam klystron, magnetic refrigerator and kibble balance.  He is an active Sr. IEEE and ASME member. Dr. Choi has published more than 30 papers in peer-reviewed journals and conferences.