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torque production mechanism of switched reluctance machines with field modulation principle

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中国科学:技术科学英文版 2023年第9期66卷 2743-2754页

作者： SUN YuHua ZHAO WenXiang JI JingHua LING ZhiJian CHEN YiFan BIANCHI Nicola School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China School of Industrial Engineering University of PadovaPadova 35131Italy

This paper aims to investigate the torque production mechanism and its improvement design in switched reluctance machines(SRMs) based on field modulation principle. Firstly, the analytical expressions of the air-gap magnetic field are derived from the perspective of DC-and AC-components, respectively. Meanwhile, different slot/pole combinations and winding arrangements are considered. Secondly, the torque productions are analyzed and evaluated with emphasis on the interaction between the DCand AC-components of air-gap fields. Thirdly, the 12-slot/8-pole and 12-slot/10-pole SRMs are established and studied by using the finite-element method. The effects of slot/pole combination and winding arrangement on the average torque production are clarified. Then, two new designs to improve the average torque are proposed. Finally, the prototype of the 12-slot/10-pole SRM is manufactured, and the experiments are carried out for validation.

关键词： switched reluctance machine(SRM) slot/pole combination winding arrangement torque field modulation principle

torque teno virus in liver diseases: On the way towards unity of view

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World Journal of Gastroenterology 2020年第15期26卷 1691-1707页

作者： Vasiliy I Reshetnyak Igor V Maev Alexandr I Burmistrov Igor A Chekmazov Tatiana I Karlovich Department of Propaedeutic of Internal Diseases and Gastroenterology A.I.Yevdokimov Moscow State University of Medicine and DentistryMoscow 127473Russia Central Clinical Hospital with Polyclinic Presidential Administration of the Russian FederationMoscow 121359Russia

The review presents the data accumulated for more than 20 years of research of torque teno virus(TTV).Its molecular genetic structure,immunobiology,epidemiology,diagnostic methods,possible replication sites,and pathogenicity factors are described.TTV is a virus that is frequently detectable in patients with different viral hepatitides,in cases of hepatitis without an obvious viral agent,as well as in a healthy population.There is evidence suggesting that biochemical and histological changes occur in liver tissue and bile duct epithelium in TTV monoinfection.There are sufficient histological signs of liver damage,which confirm that the virus can undergo a replicative cycle in hepatocytes.Along with this,cytological hybridization in TTV-infected cells has shown no substantial cytopathic(cell-damaging)effects that are characteristic of pathogenic hepatotropic viruses.Studying TTV has led to the evolution of views on its role in the development of human pathology.The first ideas about the hepatotropism of the virus were gradually reformed as new data became available on the prevalence of the virus and its co-infection with other viruses,including the viruses of the known types of hepatitides.The high prevalence of TTV in the human population indicates its persistence in the body as a virome and a nonpathogenic virus.It has recently been proposed that the level of TTV DNA in the blood of patients undergoing organ transplantation should be used as an endogenous marker of the body’s immune status.The available data show the polytropism of the virus and deny the fact that TTV can be assigned exclusively to hepatitis viruses.Fortunately,the rare detection of the damaging effect of TTV on hepatic and bile duct epithelial cells may be indirect evidence of its conditionally pathogenic properties.The ubiquity of the virus and the variability of its existence in humans cannot put an end to its study.

关键词： torque teno virus Prevalence of torque teno virus torque teno virus in liver disease Virome and torque teno virus torque teno virus and human immune status

Magnets Shifting Design of Dual PM Excited Vernier Machine for High-torque Application

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Chinese Journal of Electrical Engineering 2022年第3期8卷 90-101页

作者： Feilong Yan Jinghua Ji Zhijian Ling Yuhua Sun Wenxiang Zhao School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China

In this study,a novel dual permanent magnet excited vernier machine(DPMEVM)with magnets shifting in stator is proposed.Compared with the conventional permanent magnet synchronous machine(PMSM),the DPMEVM based on the bidirectional field modulation effect can operate in a wider torque range.However,the torque ripple of a conventional DPMEVM is high because of the superposition of the torque generated by the stator-side and rotor-side PMs.Consequently,a novel DPMEVM with magnets shifting is proposed to further reduce the torque ripple.First,the topologies and working principles of the baseline machine and proposed machines are introduced.Second,the torque-contribution harmonics are analyzed and calculated using the Maxwell tensor method.The calculation results reveal that the DPMEVM,benefiting from multiple working harmonics,can offer an enhanced torque capability compared to the PMSM.In addition,the torque ripple characteristics of the proposed machines are analyzed.It is verified that the torque ripple can be significantly reduced through magnets shifting.Third,the performances of the baseline machine and proposed machines are analyzed and compared in terms of flux density,open-circuit back-EMF,and torque characteristics.In addition,the proposed principle can be extended to machines with the same unit motor.Finally,a 120s-110p prototype machine is manufactured for validation.

关键词： Permanent magnet vernier machine bidirectional field modulation effect magnets shifting multiple working harmonics torque

torque and bending moment acting on a flexible shaft agitated by disk turbines in a gas–liquid stirred vessel

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Chinese Journal of Chemical Engineering 2019年第4期27卷 781-793页

作者： Yangyang Liang Zhengming Gao Dai'en Shi Haotian Li Yuyun Bao Ziqi Cai State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Mechanical Engineering School Yancheng Institute of Technology Yancheng 224051 China

The torque and bending moment acting on a flexible overhung shaft in a gas–liquid stirred vessel agitated by a Rushton turbine and three different curved-blade disk turbines(half circular blades disk turbine, half elliptical blades disk turbine, and parabolic blades disk turbine) were experimentally measured by a customized moment sensor. The results show that the amplitude distribution of torque can be fitted by a symmetric bimodal distribution for disk turbines, and generally the distribution is more dispersive as the blade curvature or the gas flow rate increases. The amplitude distribution of shaft bending moment can be fitted by an asymmetric Weibull distribution for disk turbines. The relative shaft bending moment manifests a "rising-falling-rising" trend over the gas flow number, which is a corporate contribution of the unstable gas–liquid flow around the impeller, the gas cavities behind the blades, and the direct impact of gas on the impeller. And the "falling" stage is greater and lasts wider over the gas flow number for Rushton turbine than for the curved-blade disk turbines.

关键词： Shaft bending moment torque Disk turbines Gas–liquid flow Fluid structure interaction

Anisotropy of Ca0.73La0.27(Fe0.96Co0.04)As2 studied by torque magnetometry

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Chinese Physics B 2020年第9期29卷 506-510页

作者：黄亚磊杨润李培刚肖宏 Department of Physics Zhejiang Sci-Tech UniversityHangzhou 310018China Center for High Pressure Science and Technology Advanced Research Beijing 100094China Laboratorium für Festkörperphysik ETH-Zürich8093ZürichSwitzerland Department of Physics Beijing University of Posts and TelecommunicationsBeijing 100876China

torque measurements were performed on single crystal samples of Ca0.73La0.27(Fe0.96Co0.04)As2 in both the normal and superconducting states.Contributions to the torque signal from the paramagnetism and the vortex lattice were identified.The superconducting anisotropy parameterγwas determined from the reversible part of the vortex contribution based on Kogan's model.It is found thatγ≈7.5 at t=T/Tc=0.85,which is smaller than the result of CaFe0.88Co0.12AsFγ≈15 at t=0.83,but larger than the result of 11 and 122 families,whereγstays in the range of 2-3.The moderate anisotropy of this 112 iron-based superconductor fills the gap between 11,122 families and 1111 families.In addition,we found that theγshows a temperature dependent behavior,i.e.,decreasing with increasing temperature.The fact thatγis not a constant point towards a multiband scenario in this compound.

关键词： torque anisotropy parameter superconductivity

Interference torque of a three-floated gyroscope with gas-lubricated bearings subject to a sudden change of the specific force

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Chinese Journal of Aeronautics 2019年第3期32卷 737-747页

作者： Yan LI Fuhai DUAN School of Mechanical Engineering Dalian University of Technology

A numerical study is carried out to investigate the influence of a sudden change of the specific force on a three-floated gyroscope with a rotor supported on gas-lubricated bearings.The interference torque is calculated to evaluate the influence by modeling the transient behavior of the rotor-bearing system. In combination with dynamic equations of the rotor displacement,the Reynolds equation is solved on the surface of spiral-grooved conical bearings. It is assumed that a steady state has been obtained with a constant specific force, and then the specific force is suddenly changed and maintained constant after that. Responses of the sudden change are obtained by solving the equations. Numerical results show that the direction of the sudden change of the specific force is the main factor which influences the interference torque curve. With a sudden change along the input direction, the interference torque fluctuation has a constant frequency and a decreasing amplitude. With a sudden change along the output direction, the interference torque fluctuates in a small range. With a sudden change along the spin direction, the change of the interference torque combines a fluctuation and a gradually-changing quasi-equilibrium value. This study provides a supplement to the steady-state error model of the three-floated gyroscope.

关键词： Conical bearing Gas lubricated bearings Interference torque Rotor-bearing system Three-floated gyroscope

torque Calculation of Five-Phase Synchronous Reluctance Motors With Shifted-Asymmetrical-Salient-Poles Under Saturation Condition

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CES Transactions on Electrical Machines and Systems 2020年第2期4卷 105-113页

作者： Qian Chen Xuping Shi Gaohong Xu Wenxiang Zhao School of Electrical and Information Engineering Jiangsu UniversityZhenjiang212013China

In traditional analytical method(AM),the magnetic saturation is always ignored to simplify the calculation process.However,synchronous reluctance motors(SynRMs)often operate around saturation point to achieve higher torque density.Therefore,a new AM is proposed,in which the saturation of stator iron has been considered.The key of the proposed method includes a saturation factor,and an iterative method is adopted to compute the saturation factor in the SynRM by increasing the air-gap length.Especially,the proposed AM can be applied to a SynRM even with shifted-asymmetrical-salient-poles.In the process of AM,the expression of stator magnetomotive force(MMF)is built firstly.Additionally,the air-gap density including slotting effect and salient-poles is calculated.Then,the rotor MMF under saturation of the stator iron is obtained.Therefore,the precision of the instantaneous torque can be improved significantly.Eventually,by the verification of finite elements method(FEM)and experiments,the torque performance of SynRMs with shifted asymmetrical rotor can be predicted accurately by the proposed AM.

关键词： Synchronous reluctance motors torque shifted asymmetrical salient pole analytical method,saturation.

Modal analysis of the torque converter in different prestress

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High Technology Letters 2020年第1期26卷 61-67页

作者：张泽宇 Hui Jizhuang Shi Ze Suo Xuefeng Zhang Xuhui Fan Hongwei Key Laboratory of Road Construction Technology and Equipment Ministry of EducationChang'an UniversityXi'an 710064P.R.China Shaanxi Key Laboratory of Mine Electromechanical Equipment Intelligent Monitoring Xi'an University of Science and TechnologyXi'an 710054P.R.China Research Center Tibet Tianlu Co.LtdLhasa 850000P.R.China

In order to study the mechanical properties and the dynamic performance of torque converter,to reduce the vibration and noise during the operation and to improve the stability,a 215 mm hydraulic torque converter is taken as the research object,and modal analyses are performed based on the finite element method.The weak parts of the impeller structure are obtained after calculating the models of the impeller and turbine without prestress.The variation of the modal frequency of the turbine and impeller are obtained under different prestress conditions by calculating different rotational speeds of the transmission shaft.The fundamental frequencies of the impeller and the turbine increase by 0.43%and 4.82%respectively when the rotational speed ranges from 100 rpm to 4500 rpm.The results of the present research indicate that the modal frequencies at different speeds are similar to the fundamental frequencies of the structure.Therefore,it is possible to estimate the vibration characteristics of the structure and optimize the structural design by numerical modal analysis in the static state instead of the dynamic state.

关键词： hydraulic torque converter modal analysis prestress finite element analysis

GFTSM-based Model Predictive torque Control for PMSM Drive System With Single Phase Current Sensor

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自动化学报 2017年第9期43卷 1644-1655页

作者： Qingfang Teng Yuxing Jin Shuyuan Li Jianguo Zhu Youguang Guo Department of Automation and Electrical Engineering Lanzhou Jiaotong University Key Laboratory of Opto-Technology and Intelligent Control Ministry of Education Lanzhou 730070 Graduate Management Team Department Engineering University of Armed Police Force Xi'an 710000 School of Electrical Mechanical and Mechatronic Systems University of Technology Sydney (UTS) Australia Sydney 2007

A global fast terminal sliding mode (GFTSM)-based model predictive torque control (MPTC) strategy is developed for permanent magnet synchronous motor (PMSM) drive system with only one phase current sensor.Generally two phase-current sensors are indispensable for MPTC.In response to only one phase current sensor available and the change of stator resistance,a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC.Moreover,in view of the variation of system parameters and external disturbance,a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness.In this paper,the GFTSM,based on sliding mode theory,employs the fast terminal sliding mode in both the reaching stage and the sliding stage.The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors.On the other hand,compared with proportional-integral (PI)-based and sliding mode (SM)-based MPTC PMSM drive systems,it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion (THD) index of three-phase stator currents in the presence of variation of load torque.The simulation results validate the feasibility and effectiveness of the proposed scheme.

关键词： Adaptive observer current sensorless global fast terminal sliding mode (GFTSM) model predictive torque control (MPTC) permanent magnet synchronous motor (PMSM)