General Airgap Field Modulation Theory for Electrical Machines

Cheng, Ming; Han, Peng; Wang, Hua

doi:10.1109/tie.2017.2682792

Cited by 416 publications

(138 citation statements)

References 39 publications

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“…This also means that the magnetic field modulation of the hybrid rotor is better than that of the magnetic barrier counterpart. Although the magnetic field modulation behavior shifts the distribution of magnetic field, the total power content is kept constant no matter what kind of modulation is used [23]. In order to evaluate the modulation efficacy, the modulation factor (M f ) is defined as the ratio of the effective modulated MMF components to total MMF component.…”

Section: Ieee Transactions On Industrial Electronicsmentioning

confidence: 99%

Design and Performance Comparisons of Brushless Doubly Fed Generators With Different Rotor Structures

Zhang

Wang

et al. 2019

IEEE Trans. Ind. Electron.

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Abstract-The Brushless Doubly-Fed Generator (BDFG) shows the great potential for use in large variable speed wind turbines due to its high reliability and cost benefits of a partially-rated power electronics converter. However, it suffers from the compromised efficiency and power factor in comparison with conventional doubly fed induction or synchronous generators. Therefore, optimizing the BDFG, especially the rotor, is necessary for enhancing its torque density and market competitiveness. In this paper, a novel cage-assisted magnetic barrier rotor, called the hybrid rotor, is proposed and analyzed. The detailed analytical design approaches based on the magnetic field modulation theory are investigated. In addition, the machine losses and mutual inductance values using the proposed rotor designs are calculated and their performance implications evaluated. Finally, the comparative experimental results for two BDFG prototypes are presented to verify the accuracy and effectiveness of the theoretical studies.

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Section: Ieee Transactions On Industrial Electronicsmentioning

confidence: 99%

Design and Performance Comparisons of Brushless Doubly Fed Generators With Different Rotor Structures

Zhang

Wang

et al. 2019

IEEE Trans. Ind. Electron.

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“…It should be noted that for FSCW PMSMs injected with sine wave current, only the prth PM field harmonic is the working harmonic in the air-gap [18] [27]. Hence, the magnetic gearing effect in FSCW PMSMs can be further described as: the armature reaction harmonic is modulated to the fundamental order by the stator slots, it can interact with the fundamental PM harmonic and produce steady torque.…”

Section: This Means Principle Of Conventional Pm Machines (8-a)mentioning

confidence: 99%

“…Recently, the modulation effect in electrical machines has drawn researchers' attention [18] mainly because the average torque can be produced by two magnetic field with different pole numbers after modulation. This phenomenon is termed as airgap field modulation and/or magnetic gearing effect, which has been proven to be the working principle of magnetic gear [19] and magnetic geared machines [20] such as Vernier [21] [22], flux-modulated [23] and switched flux (SF) [24] [25] machines.…”

Section: Introductionmentioning

confidence: 99%

“…It can be seen that the 8-pole-12-slot model and its FEA-based ECSM have the same main flux, the only difference between them is that the 8-pole-12-slot model has slot opening leakage flux whereas its FEA-based ECSM does not due to different position of coils. Since only the fundamental harmonic contributes to the average torque [18], the amplitude and phase of the 4th harmonic, which is the fundamental harmonic in 8-pole-12-slot machine, is given in Table IV. It can be seen that although the amplitudes of the corresponding harmonics in different models are not the same, the harmonics of the same order are in phase.…”

Section: A Introduction Of the Fea-based Ecsmmentioning

confidence: 99%

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Analysis of Air-Gap Field Modulation and Magnetic Gearing Effect in Fractional-Slot Concentrated-Winding Permanent-Magnet Synchronous Machines

Zhu

Liu

2018

IEEE Trans. Ind. Electron.

186

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Abstract-In this paper, the torque production of fractional slot concentrated winding (FSCW) permanent magnet synchronous machines (PMSM) are analyzed from the perspective of the air-gap field harmonics modulation accounting for slotting effect. It is found that the average torque of FSCW PMSM is produced by both the principle of conventional PMSM and the magnetic gearing effect. A finite element analysis (FEA)-based equivalent current sheet model and harmonic restoration method is firstly used in FSCW PM machines with different slot-pole number combinations to quantify the respective contribution of the conventional PMSM and the magnetic gearing effect to the average torque. The influence of slot opening on the magnetic gearing effect, cogging torque and torque ripple is analyzed. The results show that the magnetic gearing effect makes a non-ignorable contribution to the average torque when a large slot opening stator is used. The expression of the gear ratio in FSCW PMSMs is derived. The influence of gear ratio on the contribution of the magnetic gearing effect to the total torque is investigated by FEA. The FEA predicted torques are validated by experiments on the prototypes.

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“…In recent years, borrowing the idea of setting a magnetomotive force (MMF) source in the stator side of stator-excitation machines, such as flux-switching machine and flux-reversal machine [8][9][10][11][12][13], a kind of high-temperature superconducting (HTS) machine with a stationary seal was proposed and investigated [14][15][16]. Since their HTS field-excitation windings are installed in the stator side, the coupling device for cryogenic transfer can be removed, hence transforming the rotating seal into a stationary seal and simplifying the structure of the cooling system.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Characteristics Analysis of a High-Temperature Superconducting Field-Modulation Double-Stator Machine with Stationary Seal

et al. 2018

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This paper has proposed a high temperature superconducting (HTS) field-modulation double-stator (HTS-FMDS) machine with a stationary seal for low-speed and direct-drive applications. The originality of this paper lies in the HTS field-excitation windings, which were fed with a direct current in order to offer strong field excitation, were placed in the inner stator, while the armature windings were installed in the outer stator so that the stationary seal of the cryogenic cooling system could be achieved. Moreover, a ferromagnetic ring was mounted on the top of each HTS coil to prevent the quench of the HTS wires resulting from the armature-reaction magnetic-field. By using finite-element analysis (FEA), the influence of the armature-reaction magnetic-field on the critical current and the electromagnetic properties were carried out so as to verify the validity of the proposed machine.

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General Airgap Field Modulation Theory for Electrical Machines

Cited by 416 publications

References 39 publications

Design and Performance Comparisons of Brushless Doubly Fed Generators With Different Rotor Structures

Design and Performance Comparisons of Brushless Doubly Fed Generators With Different Rotor Structures

Analysis of Air-Gap Field Modulation and Magnetic Gearing Effect in Fractional-Slot Concentrated-Winding Permanent-Magnet Synchronous Machines

Electromagnetic Characteristics Analysis of a High-Temperature Superconducting Field-Modulation Double-Stator Machine with Stationary Seal

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