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313 results on '"Ji, Jinghua"'

18. Investigation of Winding Configuration on Electromagnetic Vibration in Modular Dual Three-Phase PM Machine

Author

Zhao, Wenxiang, He, Qingjun, Tian, Wei, Sun, Yuhua, and Ji, Jinghua

Abstract

This article investigates the effect of winding configuration on the electromagnetic vibration of the 48-slot/8-pole modular dual three-phase (DTP) permanent magnet (PM) machine. First, two winding topologies are discussed based on the phase shift principle, and their phase shift angles are 30° and 60°, respectively. Second, the armature magnetomotive force (MMF) of different winding configurations is derived and compared. The modular DTP-PM machine with 30° phase shift produces the extra 2nd, 18th, 22nd, 26th, and 30th armature MMF harmonic components compared with the 60° phase shift one. Afterward, the electromagnetic force density and radial concentrated force of two modular DTP-PM machines are investigated. The result reveals that the modular DTP-PM machine with 30° phase shift induces the non-negligible 2nd-order vibration under the load condition. This is different from the modular DTP-PM machine with a 60° phase shift which mainly induces 0th-order vibration. Furthermore, the multiphysics field finite-element method is used to calculate the static deformation and vibration acceleration of two modular DTP-PM machines. Finally, the prototype of a 48-slot/8-pole modular DTP-PM machine with a 30° phase shift is manufactured. The experiments are conducted to validate the theoretical analysis.

Published
2024
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19. A Novel Discrete EMN for Electromagnetic Force and Vibration Computation of SPM Machine Considering Carrier Harmonics

Author

Zhao, Wenxiang, Liu, Tong, Ji, Jinghua, Zhu, Shengdao, and Cao, Donghui

Abstract

This article proposes a discrete equivalent magnetic network (EMN) for electromagnetic force and vibration computation of surface-mounted permanent magnet (SPM) machines considering carrier harmonics. First, a new triangle permeance element is proposed and adopted for air-gap meshing of a 12-slot/10-pole SPM machine. Second, the discrete modeling method is applied in the rotor with eccentric magnets of the machine. The proposed method can decouple the relationship between the number of permeances and the transient solution step size in the interface region. Third, this method uses the current dataset involving carrier harmonics as input excitation to calculate the electromagnetic force. Then, the vibration response is synthesized by electromagnetic force and vibration transfer function. Finally, the computation accuracy and efficiency of this method are validated through the finite element method and experimental test.

Published
2024
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20. Improving Torque Analysis and Design Using the Air-Gap Field Modulation Principle for Permanent-Magnet Hub Machines.

Author

Sun, Yuhua, Bianchi, Nicola, Ji, Jinghua, and Zhao, Wenxiang

Subjects
TORQUE, PERMANENT magnets, ACTINIC flux, MACHINERY, MAGNETIC fields, MAGNETS
Abstract

The Double Permanent Magnet Vernier (DPMV) machine is well known for its high torque density and magnet utilization ratio. This paper aims to investigate the torque generation mechanism and its improved design in DPMV machines for hub propulsion based on the field modulation principle. Firstly, the topology of the proposed DPMV machine is introduced, and a commercial PM machine is used as a benchmark. Secondly, the rotor PM, stator PM, and armature magnetic fields are derived and analyzed considering the modulation effect, respectively. Meanwhile, the contribution of each harmonic to average torque is pointed out. It can be concluded that the 7th-, 12th-, 19th- and 24th-order flux density harmonics are the main source of average torque. Thanks to the multi-working harmonic characteristics, the average torque of DPMV machines has significantly increased by 31.8% compared to the counterpart commercial PM machine, while also reducing the PM weight by 75%. Thirdly, the auxiliary barrier structure and dual three-phase winding configuration are proposed from the perspective of optimizing the phase and amplitude of working harmonics, respectively. The improvements in average torque are 9.9% and 5.4%, correspondingly. [ABSTRACT FROM AUTHOR]

Published
2023
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43. Decoupled Fault-Tolerant Model Predictive Current Control for Dual Three-Phase PMSMs With Harmonic Compensation.

Author

Cui, Jia, Ji, Jinghua, Zhao, Wenxiang, Tao, Tao, Huang, Linsen, and Tang, Hongyu

Abstract

This article proposes a decoupled fault-tolerant model predictive current control for a dual three-phase permanent magnet synchronous motor with harmonic compensation. The harmonics caused by nonsinusoidal back electromotive force can be well controlled under the open-circuit fault scenario by designing a harmonic closed-loop scheme. First, a decoupled predictive model and fault-tolerant voltage vectors are deduced based on a reduced-dimension matrix, which can eliminate the coupling issues between the harmonic and fundamental subspaces. Afterward, a uniform harmonic-free virtual vector is constructed by rearranging the irregular voltage vectors. More importantly, a virtual null vector is designed in the scheme, where the virtual null vector is effective in the harmonic subspace and has no components in the fundamental subspace. So, the harmonics can be further controlled without affecting torque and flux generation. Extensive experimental results verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Published
2023
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