Study of Retaining Sleeve and Conductive Shield and Their Influence on Rotor Loss in High-Speed PM BLDC Motors

Zhou, Fang; Shen, Jinwen; Fei, W.; Lin, Ru

doi:10.1109/tmag.2006.879434

Cited by 97 publications

(22 citation statements)

References 7 publications

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“…Note that whether or not a SC improves the electromagnetic properties strongly depends on the machine's geometry and its stator-current density. Zhou et al have, for example successfully used a SC to reduce the rotor loss of a high-speed PMSM [14].…”

Section: Validationmentioning

confidence: 99%

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Study of the Effect of a Shielding Cylinder on the Torque in a Permanent-Magnet Synchronous Machine Considering Two Torque-Producing Mechanisms

2017

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Despite an ever-growing interest, a lot of questions related to the design and operation of high-speed permanent-magnet synchronous machines remain unanswered. One aspect of such high-speed machines that requires special attention is the effect of the shielding cylinder, a conductive sleeve that is wrapped around the magnets and which' goal is to reduce the rotor losses and/or retain the magnets. Therefore this work aims at theoretically studying the effect of the shielding cylinder on the torque production. The study is performed using a 2D analytical subdomain model that accounts for slotting and the eddy-current reaction field. The torque is divided in two components, the classical torque due to interaction between the magnets and the stator currents and the torque due to interaction with the eddy-currents in the shielding cylinder. This approach is unique and results in a better insight in the machine's physics.

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Section: Validationmentioning

confidence: 99%

“…The expectation is thus that the evolution of T net (t SC ) may be predicted using (11), where t AG,ef f is calculated as in (14).…”

Section: Parameter Studymentioning

confidence: 99%

Study of the Effect of a Shielding Cylinder on the Torque in a Permanent-Magnet Synchronous Machine Considering Two Torque-Producing Mechanisms

2017

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“…The thickness of the copper shield is selected based on the skin depth of either the current time-harmonics [13] assuming that the space-harmonic has little effect, or based on the spaceharmonics assuming that the current is purely sinusoidal [14]. However, if the machine operates at variable frequencies and current modulations, the harmonics and their skin depths will also vary.…”

Section: Electromagentic Analysismentioning

confidence: 99%

“…These papers stated that the copper shield reduces the rotor loss at high-speeds, whereas magnet segmentation is preferred for low speeds. In [11], space-harmonic analyses of several SPM machine topologies were used to assist the design of high-speed rotors with copper shielding and/or magnet segmentation, and in [12], time-harmonic analyses of a SPM machine to assist the design is used.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic and mechanical analysis of high speed SPM rotor with copper shield

Al-Ani

Barrans

Carter

2017

2017 IEEE International Electric Machines and Drives Conference (IEMDC)

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For high-speed applications, the surface-mounted permanent magnet (SPM) machine is preferred due to its high torque density and efficiency. However, induced eddy currents in the rotor conductive parts result in a loss of efficiency and rotor heating. Therefore, several methods to reduce such losses have been proposed in the literature including copper shielding. In this paper, a high-speed SPM machine rotor with a copper shield is designed and investigated both electromagnetically and mechanically. Several quantitative investigations including placing the copper sheet around the retaining sleeve or magnets, different copper sheet and airgap thicknesses, different retaining sleeve materials, different harmonic contents in the current waveform, i.e. pulse amplitude modulation (PAM) and pulse width modulation (PWM) generated waveforms, and different frequencies and current levels are reported. Additionally, a mechanical analysis investigating possible failure modes of the rotor with the copper sheet is reported.

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“…Several methods have been proposed to reduce the rotor eddy current loss. These methods can be summarized as: 1) external inductance to smooth the current waveform [2], 2) closed-slot and slotless topologies to reduce stator space harmonics [3][4], 3) axial and radial segmentation of the PMs or axial segmentation of the sleeve as a solution for the eddy currents [5][6], 4) sleeve shaping (groove or gaps) to cut the eddy current path [7][8], 5) pulse amplitude modulation (PAM) to reduce the effective current ripple [9], 6) high conductive shielding of harmonic effect [10][11], and 7) large airgap to reduce the effect of space harmonics [12].…”

Section: Introductionmentioning

confidence: 99%

Rotor loss reduction using segmented inverter in surface-mounted permanent magnet drive

Al-Ani

Barrans

Carter

2017

2017 IEEE International Electric Machines and Drives Conference (IEMDC)

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In this paper, the influence of different switching modulation arrangements, i.e. current waveform modulation-and phase-shift, on the resultant current waveform of an electrical machine drive consisting of a two segment inter-leaved inverter feeding a surface-mounted permanent magnet (SPM) machine with two identical sets of three phase windings is investigated. The modulation-and phase-shift have been illustrated and the influence of the different modulation and frequency indices have been studied. Furthermore, the torque, and rotor eddy currents and core losses are calculated using FEA when either modulationshifted or phase-shifted current waveforms are generated and fed to the machine. It is found that using modulation-shift can reduce the current harmonic substantially however the inverter requires two sets of input signals. On the other hand, although the current harmonic reduction is less than that of the modulation-shift, the phase-shift layout can be employed using one set of input signals with a signal delay.

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Study of Retaining Sleeve and Conductive Shield and Their Influence on Rotor Loss in High-Speed PM BLDC Motors

Cited by 97 publications

References 7 publications

Study of the Effect of a Shielding Cylinder on the Torque in a Permanent-Magnet Synchronous Machine Considering Two Torque-Producing Mechanisms

Study of the Effect of a Shielding Cylinder on the Torque in a Permanent-Magnet Synchronous Machine Considering Two Torque-Producing Mechanisms

Electromagnetic and mechanical analysis of high speed SPM rotor with copper shield

Rotor loss reduction using segmented inverter in surface-mounted permanent magnet drive

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