Cogging torque of permanent magnet electric machiens: An overview

Guo, Zhenhong; Chang, Liuchen; Xue, Yaosuo

doi:10.1109/ccece.2009.5090310

Cited by 11 publications

(3 citation statements)

References 35 publications

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“…The basic principle is that neglecting the variation in magnets and iron of PMBLDC motor, the cogging torque of an ideal lossless PMBLDC motor can be expressed as the derivative of co-energy in the air gap [25]. According to [26], cogging torque is produced because of the interaction between the PMs and the armature and the slot. Because of this interaction in the absence of a current, energy variation occurs inside the motor.…”

Section: Analytical Expression Of Cogging Torque By Vwmmentioning

confidence: 99%

Reduction of Cogging Torque in Surface Mounted Permanent Magnet Brushless DC Motor by Adapting Rotor Magnetic Displacement

Anuja

Doss

2021

Energies

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Cogging torque is a critical dilemma in Permanent Magnet Brushless DC (PMBLDC) motors. In medium-low power PMBLDC motors, redundant vibrations and forbidding noises arise as a result of the harmonic magnetic forces created by cogging torque. This paper introduces a simple approach for minimizing cogging torque in PMBLDC motors by applying placement irregularities in rotor magnets. An angle shift in the rotor magnets in surface-mounted PMBLDC motors helps to attain magnet displacement. This displacement imparts an asymmetrical magnet structure to the rotor. Maintaining pole arc to pole pitch ratio (L/τ) of between 0.6 and 0.8, shifting angles from 1° to 8° were considered in order to analyze the effect of the angle shift on the rotor magnets. An analytical expression was also derived for finding the shifting angle with the minimum cogging torque in the PMBLDC motor by using the Virtual Work Method (VWM). The optimization of the shifting angle with minimum cogging torque was investigated using 3D Finite Element Analysis (FEA). A comparison of the simulation and analytical results of cogging torque was carried out. It was determined that the reduction of cogging torque in the analytical results showed good agreement with the FEA analysis.

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Section: Analytical Expression Of Cogging Torque By Vwmmentioning

confidence: 99%

Reduction of Cogging Torque in Surface Mounted Permanent Magnet Brushless DC Motor by Adapting Rotor Magnetic Displacement

Anuja

Doss

2021

Energies

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show abstract

“…However, when the HEMS have only permanent magnets as the source of magnetic potential, the interaction between the permanent magnets and the slotted stator core inevitably generates a cogging torque. The cogging torque can cause the machine to vibrate and make noise, which affects the smooth operation of the machine [13]. Therefore, the study and reducing of the cogging torque of the HEMS are necessary.…”

Section: Introductionmentioning

confidence: 99%

A method of reducing the cogging torque in a flux-torque regulation hybrid excitation machine with axial-radial magnetic circuit

Qiu,

Duan,

Yang

2023

Preprint

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In order to solve the problem of insufficient torque for flux weakening in permanent magnet machines, a novel flux-torque regulation hybrid excitation machine with axial-radial magnetic circuit (FTRHEM) is proposed. To solve the problem that the cogging torque of the proposed machine is caused by multiple factors and the coupling relationship is complicated, an analytical expression for the cogging torque is derived first. Then, the influence of the axial excitation device on the cogging torque is determined. The influence mechanism of the relative positions between the axial excitation device and stator on the cogging torque is revealed. A dislocation method is proposed to reduce the cogging torque, and its effectiveness is verified by the finite element analysis (FEA). Furthermore, the reduction of the cogging torque in FTRHEM with different pole-slot combinations by this method is comprised and analyzed, which demonstrates the feasibility of the method. Finally, the FEA results are combined with experiments to verify the accuracy of simulations.

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“…OSTLY, Permanent magnet (PM) motors suffer from a common problem called cogging torques. Carious cogging torque reduction strategies like skewing, pole pitch optimization, pole shape optimization, and usage of fractional slot/pole were proposed by [1]- [2]. A new stator and rotor pole design for BLDC motor to reduce torque fluctuation.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Various Laminating Materials for Interior Permanent Magnet Brushless DC Motor for Cooling Fan Application

Infantraj,

Augustine,

Raj

et al. 2023

Trans. Electr. Mach. Syst.

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Cogging torque of permanent magnet electric machiens: An overview

Cited by 11 publications

References 35 publications

Reduction of Cogging Torque in Surface Mounted Permanent Magnet Brushless DC Motor by Adapting Rotor Magnetic Displacement

Reduction of Cogging Torque in Surface Mounted Permanent Magnet Brushless DC Motor by Adapting Rotor Magnetic Displacement

A method of reducing the cogging torque in a flux-torque regulation hybrid excitation machine with axial-radial magnetic circuit

Investigation of Various Laminating Materials for Interior Permanent Magnet Brushless DC Motor for Cooling Fan Application

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