In this study,a novel rotor sleeve for permanent-magnet(PM)machines equipped with fractional-slot concentrated-windings(FSCW)is proposed.With the newly designed rotor sleeve,the rotor eddy-current(EC)losses are signif...In this study,a novel rotor sleeve for permanent-magnet(PM)machines equipped with fractional-slot concentrated-windings(FSCW)is proposed.With the newly designed rotor sleeve,the rotor eddy-current(EC)losses are significantly reduced,and the torque density of the machine is improved.First,the rotor EC losses of a surface-mounted PM machine with the sleeve are analyzed.Meanwhile,the sleeve EC barriers and PM segmentation technologies for the suppression of the rotor EC losses are evaluated.Subsequently,an FSCW PM machine with the newly designed sleeve is proposed and optimized for a given set of specifications.Its electromagnetic and mechanical performances are evaluated by the finite element method(FEM).Finally,three assembling methods are presented and assessed comprehensively in terms of their merits and drawbacks.展开更多
Considering the elastic supports,the finite element model of rotor-bladed disk-casing system is established using commercial software ANSYS/LS-DYNA.Assuming that broken blade is released from the disk,the complicate r...Considering the elastic supports,the finite element model of rotor-bladed disk-casing system is established using commercial software ANSYS/LS-DYNA.Assuming that broken blade is released from the disk,the complicate rubbing responses of unbalanced rotor-bladed disk-casing system are studied under different operational speeds.In addition,influences of both plastic deformation of blade and casing failure are analyzed.The results show that there exist some multiple even fractional frequencies in the transient and steady vibration responses of unbalanced rotor.Besides,one nodal diameter vibration of bladed disk coupling with the lateral vibration of the shaft as well as the first order bending vibration of blade can be excited under low operational speed,while the first order bending vibration of blade coupling with the lateral vibration of disk-shaft is easily excited under high operational speed.During rubbing process,three distinct contact states can be observed:broken blade-casing contact,broken blade-blade component-casing contact and broken blade-casing contact/blade component-casing contact/blade selfcontact.It is worth noting that the third contact state is related to the operational speed.With the increase of operational speed,self-contact in the blade may occur.展开更多
The aim of this paper is to present the eddy current losses in solid pole shoes in a permanent magnet two-pole electric motor. In the presented paper, the authors have chosen to work with three different analytical mo...The aim of this paper is to present the eddy current losses in solid pole shoes in a permanent magnet two-pole electric motor. In the presented paper, the authors have chosen to work with three different analytical models, Carter’s theory, Gibb’s theory and Lawrenson’s theory, each with different degree of accuracy and simplifications. The results from the analytical models all present relatively low eddy current losses, giving the designer valuable arguments to utilize solid pole shoes, as a rotor with solid poles is from a construction point of view a more suitable choice, increasing the mechanical stability and reducing the production cost, compared to the laminated design.展开更多
Manipulating biomacromolecules and micro-devices with light is highly appealing.Opto driving torque can propel micro-rotors to translational motion in viscous liquid,and then separate microsystems according to their h...Manipulating biomacromolecules and micro-devices with light is highly appealing.Opto driving torque can propel micro-rotors to translational motion in viscous liquid,and then separate microsystems according to their handedness.We study the torque of dielectric loss generated by circular polarized lasers.The unwanted axial force which causes the handedness independent translational motion is cancelled by the counter propagating reflection beams.The propelling efficiency and the friction torque of water are obtained by solving the Navier-Stokes equation.In the interesting range of parameters,the numerical friction torque is found to be linear to the angular velocity with a slope depending on the radius of rotor as r^3.The time-dependent distribution of angular velocity is obtained as a solution of the Fokker-Planck equation,with which the thermal fluctuation is accounted.The results shed light on the micro-torque measurement and suggest a controllable micro-carrier.展开更多
基金Supported by the National Natural Science Foundation of China(51991383)the Natural Science Foundation of Jiangsu Province(BK20171298)+1 种基金the Graduate Scientific Research Innovation Project of Jiangsu Province(KYCX18_2248)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘In this study,a novel rotor sleeve for permanent-magnet(PM)machines equipped with fractional-slot concentrated-windings(FSCW)is proposed.With the newly designed rotor sleeve,the rotor eddy-current(EC)losses are significantly reduced,and the torque density of the machine is improved.First,the rotor EC losses of a surface-mounted PM machine with the sleeve are analyzed.Meanwhile,the sleeve EC barriers and PM segmentation technologies for the suppression of the rotor EC losses are evaluated.Subsequently,an FSCW PM machine with the newly designed sleeve is proposed and optimized for a given set of specifications.Its electromagnetic and mechanical performances are evaluated by the finite element method(FEM).Finally,three assembling methods are presented and assessed comprehensively in terms of their merits and drawbacks.
基金supported by the National Natural Science Foundation of China(No.11772089)the Fundamental Research Funds for the Central Universities (Nos. N160312001and N160313004)the Research Project of State Key Laboratory of Mechanical System and Vibration(No.MSV201707)
文摘Considering the elastic supports,the finite element model of rotor-bladed disk-casing system is established using commercial software ANSYS/LS-DYNA.Assuming that broken blade is released from the disk,the complicate rubbing responses of unbalanced rotor-bladed disk-casing system are studied under different operational speeds.In addition,influences of both plastic deformation of blade and casing failure are analyzed.The results show that there exist some multiple even fractional frequencies in the transient and steady vibration responses of unbalanced rotor.Besides,one nodal diameter vibration of bladed disk coupling with the lateral vibration of the shaft as well as the first order bending vibration of blade can be excited under low operational speed,while the first order bending vibration of blade coupling with the lateral vibration of disk-shaft is easily excited under high operational speed.During rubbing process,three distinct contact states can be observed:broken blade-casing contact,broken blade-blade component-casing contact and broken blade-casing contact/blade component-casing contact/blade selfcontact.It is worth noting that the third contact state is related to the operational speed.With the increase of operational speed,self-contact in the blade may occur.
文摘The aim of this paper is to present the eddy current losses in solid pole shoes in a permanent magnet two-pole electric motor. In the presented paper, the authors have chosen to work with three different analytical models, Carter’s theory, Gibb’s theory and Lawrenson’s theory, each with different degree of accuracy and simplifications. The results from the analytical models all present relatively low eddy current losses, giving the designer valuable arguments to utilize solid pole shoes, as a rotor with solid poles is from a construction point of view a more suitable choice, increasing the mechanical stability and reducing the production cost, compared to the laminated design.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB933601)the National Key Research and Development Project of China(Grant No.2016YFA0202001)the Special Program for Applied Research on Super Computation of the NSFC–Guangdong Joint Fund(the second phase)
文摘Manipulating biomacromolecules and micro-devices with light is highly appealing.Opto driving torque can propel micro-rotors to translational motion in viscous liquid,and then separate microsystems according to their handedness.We study the torque of dielectric loss generated by circular polarized lasers.The unwanted axial force which causes the handedness independent translational motion is cancelled by the counter propagating reflection beams.The propelling efficiency and the friction torque of water are obtained by solving the Navier-Stokes equation.In the interesting range of parameters,the numerical friction torque is found to be linear to the angular velocity with a slope depending on the radius of rotor as r^3.The time-dependent distribution of angular velocity is obtained as a solution of the Fokker-Planck equation,with which the thermal fluctuation is accounted.The results shed light on the micro-torque measurement and suggest a controllable micro-carrier.
