Electromagnetic Bearings with Power Electronic Control for High-Speed Rotating Machines: Review, Analysis, and Design Example

Prasad, KNV and Narayanan, G (2021) Electromagnetic Bearings with Power Electronic Control for High-Speed Rotating Machines: Review, Analysis, and Design Example. In: IEEE Transactions on Industry Applications, 57 (5). pp. 4946-4957.

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Abstract

This article reviews electromagnetic bearings with power electronic control for high-speed machinery, which are termed active magnetic bearings (AMBs). AMB is a contactless-type bearing, which uses magnetic force to support the rotor. This is suitable for high-speed applications, harsh operating conditions, and also clean environments. However, the AMB has nonlinear characteristics and is inherently unstable. Due to recent advancements in fast-switching power devices, high-switching-frequency power converters, high-bandwidth current control, nonlinear control strategies, advanced digital controllers, and sensors, AMBs have become promising for high-speed aerospace, industrial, and energy applications. This article contains a brief tutorial on the AMB, covering its operating principle, system-level block diagram, magnetic-circuit-based analysis, dynamic load due to rotor mass unbalance, load capacity, force slew rate, and response to large force disturbance. Furthermore, a design example of an eight-pole AMB with four excitation coils is presented to achieve a load capacity of 180 N. A preliminary design, based on magnetic circuit analysis, is seen to fall short in terms of load capacity. Iterative changes to the AMB dimensions achieve the required load capacity, but the characteristics are still nonlinear. Finite-element analyses bring out the effects of magnetic saturation on load capacity, linearity between force and current, force slew rate, and relationships between maximum force generated and AMB dimensions. An improved design procedure is presented to achieve both desired load capacity and linear characteristics, while balancing the compactness requirement. The improved design also achieves the desired slew rate besides faster response and improved stability. © 1972-2012 IEEE.

Item Type:	Journal Article
Publication:	IEEE Transactions on Industry Applications
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to Institute of Electrical and Electronics Engineers Inc.
Keywords:	Balancing; Design; Digital devices; Dynamic loads; Industrial electronics; Magnetic bearings; Magnetic circuits; Magnetism; Nonlinear analysis; Power electronics; Servomechanisms, Active magnetic bearings; Digital controllers; Electromagnetic bearings; High-speed applications; Linear characteristics; Nonlinear characteristics; Operating principles; Power electronic control, Power control
Department/Centre:	Division of Electrical Sciences > Electrical Engineering
Date Deposited:	20 Feb 2023 11:39
Last Modified:	20 Feb 2023 11:39
URI:	https://eprints.iisc.ac.in/id/eprint/80506

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