目前,国内外对轴带发电机的研究主要集中在轴带发电机的恒速传动装置以及恒频逆变装置方面,并没有重点研究轴带发电机的结构。现代的轴带电机系统发展方向是:投资成本不断降低,运行周期内节能效益不断提高,稳定性不断改善,功能上要求具...目前,国内外对轴带发电机的研究主要集中在轴带发电机的恒速传动装置以及恒频逆变装置方面,并没有重点研究轴带发电机的结构。现代的轴带电机系统发展方向是:投资成本不断降低,运行周期内节能效益不断提高,稳定性不断改善,功能上要求具有长期并联运行能力,同时具有PTI(Power Take In)和PTO(Power Take Out)双模式运行能力。从电机结构上来说,基于轴径向复合磁场的发电机结构新颖、节省材料、高性价比、体积小,还可以通过减小电机长径比来提高电机转矩密度,将会是未来船用轴带电机的研究和发展方向。展开更多
This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machin...This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machine is obtained. Conventional bearingless machine has dual windings,levitation windings and torque windings,which produce the two magnetic fields. In the proposed bearingless motor,the two needed magnetic fields are produced by feeding two groups of currents to a single set of multiphase windings. Taking a 5-phase induction motor as example,the inductance matrices,considering air gap eccentricity,are calculated with the modified winding function method. The radial force analytical model is deduced by virtual displacement,and its results are validated by FEA. The mathematical model of the new bearingless machine is set up,and the simulation results verified the feasibility of this novel bearingless motor.展开更多
This paper describes the experimental study on shock response of FDB (fluid dynamic bearing) spindle for HDDs (hard disk drives). The FDBs are widely used as rotating shaft support elements for HDD spindle motors....This paper describes the experimental study on shock response of FDB (fluid dynamic bearing) spindle for HDDs (hard disk drives). The FDBs are widely used as rotating shaft support elements for HDD spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for various information related equipment such as mobile PCs (personal computers), video cameras, car navigation systems and so on. Hence, the rotating shaft has a possibility to come in contact with the bearing by external shocks and it causes wear or seizure to the bearing surface. To avoid the problem, it is extremely important to know how the spindle moves against the large shock on HDDs experimentally. However, as far as the authors know, there are few experimental studies treating the shock response of HDD spindles. In this paper, firstly, we propose a new test rig and experimental method for shock response of FDB spindles. Then the shock tests against the radial and axial disturbance on FDB spindle for 2.5" HDD are conducted. Finally, the experimental results of shock response waveforms and maximum displacement of disk are shown.展开更多
In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet s...In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used first to improve the torque characteristics using two-dimensional finite element analysis(FEA) in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The influences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.展开更多
文摘目前,国内外对轴带发电机的研究主要集中在轴带发电机的恒速传动装置以及恒频逆变装置方面,并没有重点研究轴带发电机的结构。现代的轴带电机系统发展方向是:投资成本不断降低,运行周期内节能效益不断提高,稳定性不断改善,功能上要求具有长期并联运行能力,同时具有PTI(Power Take In)和PTO(Power Take Out)双模式运行能力。从电机结构上来说,基于轴径向复合磁场的发电机结构新颖、节省材料、高性价比、体积小,还可以通过减小电机长径比来提高电机转矩密度,将会是未来船用轴带电机的研究和发展方向。
基金Project (No. 50677060) supported by the National Natural ScienceFoundation of China
文摘This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machine is obtained. Conventional bearingless machine has dual windings,levitation windings and torque windings,which produce the two magnetic fields. In the proposed bearingless motor,the two needed magnetic fields are produced by feeding two groups of currents to a single set of multiphase windings. Taking a 5-phase induction motor as example,the inductance matrices,considering air gap eccentricity,are calculated with the modified winding function method. The radial force analytical model is deduced by virtual displacement,and its results are validated by FEA. The mathematical model of the new bearingless machine is set up,and the simulation results verified the feasibility of this novel bearingless motor.
文摘This paper describes the experimental study on shock response of FDB (fluid dynamic bearing) spindle for HDDs (hard disk drives). The FDBs are widely used as rotating shaft support elements for HDD spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for various information related equipment such as mobile PCs (personal computers), video cameras, car navigation systems and so on. Hence, the rotating shaft has a possibility to come in contact with the bearing by external shocks and it causes wear or seizure to the bearing surface. To avoid the problem, it is extremely important to know how the spindle moves against the large shock on HDDs experimentally. However, as far as the authors know, there are few experimental studies treating the shock response of HDD spindles. In this paper, firstly, we propose a new test rig and experimental method for shock response of FDB spindles. Then the shock tests against the radial and axial disturbance on FDB spindle for 2.5" HDD are conducted. Finally, the experimental results of shock response waveforms and maximum displacement of disk are shown.
基金Project supported by the National Natural Science Foundation of China(No.51377140) the National Basic Research Program(973)of China(No.2013CB035604)
文摘In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used first to improve the torque characteristics using two-dimensional finite element analysis(FEA) in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The influences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.