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Title:High-frequency, high-pole count design for improving specific power density of electric machines
Author(s):Yoon, Andy Keehoon
Department / Program:Electrical & Computer Eng
Discipline:Electrical & Computer Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):AC Machines
high pole count
high frequency
high power density
induction machines
permanent magnet machines
Abstract:This thesis introduces the high frequency, high pole count (HFHP) design for improving specific power density of electric machines for weight and/or volume sensitive applications. Although electric machine designs have reached a limit in terms of efficiency, reliability, and cost, newer applications such as in aviation or the oil and gas industry are demanding next-generation motors to be lighter and more compact. The benefit of HFHP design is shown analytically by observing the effect of frequency and pole count on air-gap flux density and torque, while its adverse effects on magnetizing reactance, leakage reactance, and iron/copper losses are realized. The concept is applied to two of the most ubiquitous electric machines today: induction machines and permanent magnet machines. Electrical equivalent circuits are utilized to analytically hypothesize the effect of HFHP designs, then finite element models (FEM) are built to verify the effects. For induction machines, significant reduction in magnetizing reactance is shown to result in growth in line current and low torque. For permanent magnet machines, however, reduction in magnetizing reactance is shown to not directly affect torque of the machine, thus increase in specific power density is shown. The design of a 1 MW, 13 kW/kg motor is described, based on the shown benefit of HFHP design in permanent magnet machines. The motor proves that adverse effects of high frequency and high pole count are manageable by employing air-gap windings, halbach arrays, and outer rotor topology.
Issue Date:2016-04-19
Rights Information:Copyright 2016 Andy K. Yoon
Date Available in IDEALS:2016-07-07
Date Deposited:2016-05

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