Magnet Eddy Current Loss Reduction in Permanent Magnet Machines

Ma, Jie; Zhu, Z. Q.

doi:10.1109/tia.2018.2874350

Cited by 18 publications

(8 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rotor losses are mainly attributed to the eddy current losses of the PM and the shaft, which are defined by the spatial harmonics and the time harmonics [12,13]. The spatial harmonics are determined by the machine design, but the time harmonics may vary according to the vehicle operation.…”

Section: Profiling the Eddy Current Losses Variations Of High-speed P...mentioning

confidence: 99%

See 1 more Smart Citation

Profiling the Eddy Current Losses Variations of High-Speed Permanent Magnet Machines in Plug-In Hybrid Electric Vehicles

Huang

Tang

Golovanov

et al. 2022

IEEE Trans. Transp. Electrific.

View full text Add to dashboard Cite

High-speed permanent magnet (PM) machines have been recognized as a popular choice for plug-in hybrid electric vehicles (PHEVs). Although high-speed operation can enhance the machine power density, more rotor eddy current losses can be expected. Those losses dominantly result from the current harmonics that may vary during the vehicle driving cycles. Therefore, it is crucial to profile the eddy current losses variations, thus identifying the worst case. To achieve this objective, a new indicator, namely the frequency-weighted harmonics distortion (FWTH), is defined correlating with eddy current losses in this paper. Profiling eddy current losses variations by FWTH relieves the computational burden seen in the finite element analysis (FEA) as its derivation simply governs all the current harmonics. Various machine and converter operation conditions are covered in the study. The strong correlations between the addressed FWTH factor and the eddy current losses have been validated from the FEA, and then the experimental results on a 110krpm, 35kW PM machine served in PHEVs. The effectiveness of using FWTH to profile the eddy current losses variations during driving cycles has been proven, where the worst eddy current case has been identified for the tested machine.

show abstract

Section: Profiling the Eddy Current Losses Variations Of High-speed P...mentioning

confidence: 99%

“…With larger speeds, the impact of time harmonics on the eddy current losses aggravates [12,13,18]. Further, due to the physical limitation of solid-state switching devices and the switching losses considerations, the switching frequency cannot be very high [19,20].…”

Section: Profiling the Eddy Current Losses Variations Of High-speed P...mentioning

confidence: 99%

Profiling the Eddy Current Losses Variations of High-Speed Permanent Magnet Machines in Plug-In Hybrid Electric Vehicles

Huang

Tang

Golovanov

et al. 2022

IEEE Trans. Transp. Electrific.

View full text Add to dashboard Cite

show abstract

“…(17). = , (17) Where , , , , and are current density, filling factor, area of the slot, input current, and the number of turns, respectively. In the optimization process, shown in Fig.…”

Section: Figure 18 Design Parameters Of Optimizationmentioning

confidence: 99%

“…Another way to suppress the airgap permeance harmonics that caused losses is to use the PWM technique [16]; however, only time harmonics reduces in this case. Auxiliary slots in the stator teeth are proposed by [17] to reduce the PM eddy current loss, which partially decreases PM losses without lowering the amplitude of the spatial harmonics.…”

Section: Introductionmentioning

confidence: 99%

Design and Performance Investigation of 3-Slot/2-Pole High Speed Permanent Magnet Machine

Khan

et al. 2021

IEEE Access

View full text Add to dashboard Cite

High-speed rotating mechanical machinery is a developed, mature and reliable technology for many engineering applications. In high-speed permanent magnet machines, the rotor's permanent magnet PM is not strong enough to withstand the centrifugal force resulting from excessive rotational speed; thus, the PM material must be protected by a non-magnetic alloy sleeve. This paper presents a novel high-speed PM machine with solid rotor PM covered by a titanium retaining sleeve. The rotor stress condition is simplified as a plane stress problem according to the strength measurement of solid PM rotors in the high-speed PM motors. The analytical formulas for rotor stress are presented based on the polar coordinate displacement method. The proposed model is compared with a conventional model having auxiliary slots in stator teeth. Using a finite element analysis environment, the performance analysis shows that the proposed design has reduced magnet eddy current loss, cogging torque, and iron losses. The initial design is also optimized using a deterministic optimization algorithm that increases output torque by 26% compared to the initial design. INDEX TERMS Airgap flux density, finite element method, high-speed permanent magnet machine, magnet eddy current loss, retaining sleeve, rotor design, stress analysis.

show abstract

“…The rotor-shape and core optimizations can also reduce the eddy current loss of the PM. Notching in the stator teeth or introducing auxiliary slots (AS) in the stator teeth to minimize the eddy current loss of the PM were proposed by [30], [31], which partially reduced the magnet eddy current losses. However, the amplitude of the spatial harmonics was not minimized.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Design of Novel High Speed Permanent Magnet Machine Considering Magnet Eddy Current Loss

Khan

Ahmad

et al. 2020

IEEE Access

View full text Add to dashboard Cite

In high speed permanent magnet (HSPM) machines, the computation of magnet eddy current loss is essential as these losses significantly affect the temperature of the permanent magnet (PM) and electromagnetic performance and can result in irreversible demagnetization of the PM. Several techniques have been adopted to minimize the eddy current loss of the PM; however, superior performance has not been achieved yet. In this paper, the design characteristics of the HSPM machine are analyzed. The PM is covered by a titanium sleeve to retain the PM on the rotor and to further reduce the eddy current loss of the magnet. The undesirable harmonics of the airgap flux density are minimized, which reduces the eddy current loss in the solid PM and rotor. Two existing models, with and without auxiliary slots, are examined and compared with the proposed design having a titanium-based retaining sleeve. The analysis reveals that the eddy-current loss, cogging torque, and iron losses of the PM are reduced by 82%, 73%, and 44.7%, respectively, in the proposed model; however, a marginal increase is observed in the average rated torque profile and open circuit flux linkage.INDEX TERMS Auxiliary slot, eddy current losses, finite element analysis, high speed machine, iron loss, permanent magnet, sleeve, spatial harmonics.

show abstract

Magnet Eddy Current Loss Reduction in Permanent Magnet Machines

Cited by 18 publications

References 30 publications

Profiling the Eddy Current Losses Variations of High-Speed Permanent Magnet Machines in Plug-In Hybrid Electric Vehicles

Profiling the Eddy Current Losses Variations of High-Speed Permanent Magnet Machines in Plug-In Hybrid Electric Vehicles

Design and Performance Investigation of 3-Slot/2-Pole High Speed Permanent Magnet Machine

Analysis and Design of Novel High Speed Permanent Magnet Machine Considering Magnet Eddy Current Loss

Contact Info

Product

Resources

About