Study of a Combined Demagnetization and Eccentricity Fault in an AFPM Synchronous Generator

Barmpatza, Alexandra C.; Kappatou, J. C.

doi:10.3390/en13215609

Cited by 14 publications

(10 citation statements)

References 37 publications

(58 reference statements)

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“…SE and DE are caused by the eccentricity displacement between the central axis of the stator and rotor [9]. Therefore, cogging torque and torque ripple increase because the air-gap length due to SE and DE becomes nonuniform [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Diagnosis and Robust Design Optimization of SPMSM Considering Back EMF and Cogging Torque due to Static Eccentricity

Park

Kim

et al. 2021

Energies

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Static eccentricity (SE) is frequently generated by manufacturing processes. As the nonuniformity of the air-gap length is caused by the SE, the torque ripple and cogging torque increase in the motor. This study analyzes the distorted back electromotive force (EMF) and cogging torque due to SE. Further, a motor design considering SE is performed for stable back EMF and low cogging torque. First, the SE was diagnosed and analyzed using the back EMF and cogging torque measured from the test results of the base model. In addition, the rotor position was calculated using the unbalanced back EMF due to the SE. The calculated rotor position is used when analyzing phenomena due to SE and applied to robust design. Subsequently, robust design optimization was performed to improve the unbalanced back EMF and cogging torque due to SE. Using finite element analysis (FEA) considering SE, the shape of the stator was designed based on the base model. The estimated rotor position from the base model was applied to the optimum model to confirm its robustness from SE’s effects. Finally, the base and optimum models were compared through the test results.

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Section: Introductionmentioning

confidence: 99%

Diagnosis and Robust Design Optimization of SPMSM Considering Back EMF and Cogging Torque due to Static Eccentricity

Park

Kim

et al. 2021

Energies

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“…After a long-term operation in relatively harsh operating environments such as desert, gobi, and sea surface, the PM in D-PMSG may have demagnetization faults due to high temperature, chemical corrosion, mechanical vibration, and other factors [5,6]. When a large-scale generator set connected to the grid has demagnetization faults, the terminal voltage of the generator will decrease, and the generator will absorb a large amount of reactive power from the system [7], which will cause fluctuations in the electrical parameters of the power grid and affect the operation safety of the power system.…”

Section: Introductionmentioning

confidence: 99%

A Fault-Tolerant Control Strategy for D-PMSG Wind Power Generation System

Luo¹,

Peng²,

Zhang³

et al. 2022

PIER C

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Aiming at the problem of motor speed decrease in direct-drive permanent magnet synchronous generator (D-PMSG) wind power generation system after permanent magnet (PM) demagnetization faults, a demagnetization fault-tolerant control strategy in D-PMSG wind power generation system is proposed. Firstly, the D-PMSG mathematical model is described in normal and demagnetization. Secondly, an extended Kalman filter (EKF) observer is designed to observe the PM flux online. Then, flux linkage parameters are introduced into the two-vector model predictive faulttolerant control so that the increase of stator current is controlled within the limit range. Meanwhile, the motor speed can follow the change of the given speed. In addition, the improved Luenberger mechanical torque observer is designed in the speed outer ring to deal with the vibration caused by unstable wind speed. Finally, compared with the dual-closed-loop Proportional Integral (PI) control, the experimental results show that the demagnetization fault-tolerant control strategy has smaller speed overshoot and smaller speed fluctuation when the mechanical torque changes. The method can maintain the speed balance when the PM demagnetization faults occur and have stronger fault tolerance and antiinterference ability.

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“…(1) The signal-based fault diagnosis method extracts the fault characteristics from the measured signals such as voltage [ 6 , 7 , 8 ], current [ 6 , 7 , 9 , 10 ], flux [ 11 , 12 ], and torque [ 13 ] of the motor for fault diagnosis using signal processing techniques. In [ 6 ], harmonic analysis was carried out on signals such as no-load back-EMF, line current, and the zero-sequence voltage component of the motor with demagnetization faults, and the differences in the harmonic content of various signals between the healthy motor and the partially demagnetized motor were calculated; this served as the basis for diagnosing demagnetization faults.…”

Section: Introductionmentioning

confidence: 99%

Analytical Modeling and Analysis of Permanent-Magnet Motor with Demagnetization Fault

Shi

Peng²,

Zhang³

et al. 2022

Sensors

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Factors such as insufficient heat dissipation and excessively high temperature can easily lead to demagnetization of the PMs in permanent-magnet (PM) motors. As a result, the magnetic field distribution of the motor will not be uniform, producing fault harmonics and lowering the operational performance of the motor. An essential stage in the diagnosis of faults and the monitoring of motor condition is the establishment of an accurate model of motors with demagnetization faults. In this paper, demagnetization faults are modeled by changing the Fourier coefficients in the Fourier expansion of the magnetization of PMs. This model can be used to determine the motor performance under various types of demagnetization, including radial air gap flux density, back electromotive force (EMF), and torque. On this basis, the corresponding relationship between the demagnetization degree and the fault signature is established, to provide a theoretical foundation for the subsequent demagnetization fault diagnosis. The finite element analysis (FEA) verifies the effectiveness and superiority of the proposed analytical model. The modeling method proposed in this paper can be applied to PM motors with PMs having different magnetization directions and shapes because it is based on the demagnetization region of PMs.

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Study of a Combined Demagnetization and Eccentricity Fault in an AFPM Synchronous Generator

Cited by 14 publications

References 37 publications

Diagnosis and Robust Design Optimization of SPMSM Considering Back EMF and Cogging Torque due to Static Eccentricity

Diagnosis and Robust Design Optimization of SPMSM Considering Back EMF and Cogging Torque due to Static Eccentricity

A Fault-Tolerant Control Strategy for D-PMSG Wind Power Generation System

Analytical Modeling and Analysis of Permanent-Magnet Motor with Demagnetization Fault

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