Hysteresis Losses in Sintered NdFeB Permanent Magnets in Rotating Electrical Machines

Pyrhönen, Juha; Ruoho, S.; Nerg, Janne; Paju, M.; Tuominen, Sampo; Kankaanpää, H.; Stern, Raivo; Boglietti, Aldo; Uzhegov, Nikita

doi:10.1109/tie.2014.2354597

Cited by 48 publications

(20 citation statements)

References 16 publications

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“…There is a wide variety of analytical and numerical techniques for PM loss prediction [58]- [89]. The analytical techniques are based on simplified assumptions regarding the magnetic field distribution within the machine assembly, and their use is usually limited to the selected machine topologies and operating regimes.…”

Section: ) Permanent Magnet Power Lossmentioning

confidence: 99%

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Power Loss Analysis in Thermal Design of Permanent Magnet Machines – A Review

Wróbel¹,

Mellor

Popescu

et al. 2015

IEEE Trans. on Ind. Applicat.

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Section: ) Permanent Magnet Power Lossmentioning

confidence: 99%

“…These PM loss components are attributed mainly to the eddy-currents effects (Joule losses). The hysteresis loss effects in the PM material have been found to be negligible [89].…”

Section: ) Permanent Magnet Power Lossmentioning

confidence: 99%

Power Loss Analysis in Thermal Design of Permanent Magnet Machines – A Review

Wróbel¹,

Mellor

Popescu

et al. 2015

IEEE Trans. on Ind. Applicat.

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“…For some applications, especially in high-speed machines, they could become a problem [16]. In [17], it is concluded that hysteresis loss in permanent magnets do not play any significant role in electrical machines.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Permanent Magnet Demagnetization in Synchronous Machines during Multiple Short-Circuit Fault Conditions

Sjökvist

Eriksson

2017

Energies

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Faults in electrical machines can vary in severity and affect different parts of the machine. This study focuses on various kinds of short-circuits on the terminal side of a generic 20 kW surface mounted permanent magnet synchronous generator and how successive faults affect the performance of the machine. The study was conducted with the commercially available finite element method software COMSOL Multiphysics R , and two time-dependent models for demagnetization of permanent magnets were compared, one using only internal models and the other using a proprietary external function. The study is simulation based and the two models were compared to a previously experimentally verified stationary model. Results showed that the power output decreased by more than 30% after five successive faults. In addition, the no-load voltage had become unsymmetrical, which was explained by the uneven demagnetization of the permanent magnets. The permanent magnet with the lowest reduction in average remanence was decreased by 0.8%, while the highest average reduction was 23.8% in another permanent magnet. The internal simulation model was about four times faster than the external model, but slightly overestimated the demagnetization.

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“…Although there are both eddy-current loss component and hysteresis loss component occur in PMs [15], researchers always focus on eddy-current loss, with hysteresis ignored. When reviewing the existing techniques of predicting magnet loss in the rotors of PM machines, two main methods have emerged: numerical and analytical [10], [16]- [36].…”

Section: Introductionmentioning

confidence: 99%

“…This is exacerbated by difficulty of predicting rotor temperature; the rotary rotor assembly does not allow for a simple and reliable temperature monitoring and protection. Furthermore, the continuous drive towards high power-density and compact PM machine solutions imposes the requirement of elevated temperature operation to fully utilise physical properties of the active materials used.Although there are both eddy-current loss component and hysteresis loss component occur in PMs [15], researchers always focus on eddy-current loss, with hysteresis ignored. When reviewing the existing techniques of predicting magnet loss in the rotors of PM machines, two main methods have emerged: numerical and analytical [10], [16]-[36].…”

mentioning

confidence: 99%

A Computationally Efficient PM Power Loss Mapping for Brushless AC PM Machines With Surface-Mounted PM Rotor Construction

Wróbel

Mellor

et al. 2015

IEEE Trans. Ind. Electron.

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--This paper describes a computationally efficient approach for mapping the rotor power loss in permanent magnet (PM) machines. The PM loss mapping methodology discussed here utilises a small number of time-step finite element analyses (FEA) to determine the parameters of a functional representation of the loss variation with speed (frequency) and stator current, and is intended for a rapid evaluation of machine performance over entire torque-speed envelope. The research focus is placed on field-oriented controlled brushless AC PM machines with surface-mounted PM rotor construction, although the method could be adapted for other rotor formats. The loss mapping procedure accounts for the axial-segmentation of PM array through the use of an equivalent electrical resistivity of the segmented PM array, obtained from 3D FEA. The PM loss can be accurately mapped across the full operational envelope, including the field weakened mode, through a single three-dimensional (3D) and four two-dimensional (2D) time-step FEAs. The proposed methodology is validated on an 18 slots, 16 poles surfacemounted brushless AC PM machine design. The loss mapping procedure results agree closely with the computationally demanding alternative of direct 3D FE prediction of the PM power loss undertaken at each of the machine's operating points.Index Terms-PM power loss, surface-mounted brushless AC PM machines, computationally efficient methodology, loss mapping, finite element analysis (FEA), segmented PM array. I. INTRODUCTIONHE accurate prediction of loss and its variation with load is an important element in the design of electrical machines [1]. Vehicle propulsion applications are particularly demanding as the understanding of machine efficiency over the entire working envelope and under specific control and operating conditions is usually required [2]- [4]. Typically an electric propulsion motor operates under constant torque and field-weakened control regimes. Further the motor input voltage at a given operating point can be highly variable, depending on the battery state of charge. The loss derivation, in such cases, is a time demanding and computationally intensive process requiring numerous analyses to predict each component of loss over the full range of operation.In general, the sources of loss present within an electric machine can be categorised as mechanical and electromagnetic. Mechanical loss is attributed to the frictional effects within the bearing assembly (bearing loss) and fluid dynamics or aerodynamics effects within the motor body (windage or drag loss) [5]. Electromagnetic losses are usually associated with active parts of the motor assembly and include the iron, winding and permanent magnet (PM) loss components [6]- [8].Recently, there has been increased interest in methods for accurate and computationally efficient derivation of the electromagnetic loss components [1], [9], [10], that can be easily incorporated within design software tools. Of particular interest is the automated generation of loss/efficien...

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Hysteresis Losses in Sintered NdFeB Permanent Magnets in Rotating Electrical Machines

Cited by 48 publications

References 16 publications

Power Loss Analysis in Thermal Design of Permanent Magnet Machines – A Review

Power Loss Analysis in Thermal Design of Permanent Magnet Machines – A Review

Investigation of Permanent Magnet Demagnetization in Synchronous Machines during Multiple Short-Circuit Fault Conditions

A Computationally Efficient PM Power Loss Mapping for Brushless AC PM Machines With Surface-Mounted PM Rotor Construction

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