The sealing performance of magnetic fluid is related to the magnetic fluid itself. Many factors can influence the magnetic field and the seal pressure differences of magnetic fluid seals, such as the sealing gap, the ...The sealing performance of magnetic fluid is related to the magnetic fluid itself. Many factors can influence the magnetic field and the seal pressure differences of magnetic fluid seals, such as the sealing gap, the shaft eccentricity, the shaft diameter, the volume of the magnetic fluid and the centrifugal force. These factors are analyzed by numerical computation. When the seal material and structure are the same, the seal pressure difference is directly proportional to the magnetic field intensity and the saturation magnetization of the magnetic fluid. The sealing performance of the magnetic fluid will reduce with the increase of the sealing gap and shaft eccentricity. The sealing performance will increase with the volume of the magnetic fluid and decrease with the increase of the shaft diameter taking gravity into account. The increase of the shaft diameter is the same as the reduction of the volume of the magnetic fluid. The magnetic fluid cross-section can change because of the centrifugal force. Some improvements can reducc the influence of the centrifugal force. The centrifugal force can be utilized to improve the sealing performance.展开更多
The paper deals with the comparison of three different digital devices used for the computing of permanent magnet synchronous motor （PMSM） model. Model is used for virtual high frequency injection method （VHFIM） s...The paper deals with the comparison of three different digital devices used for the computing of permanent magnet synchronous motor （PMSM） model. Model is used for virtual high frequency injection method （VHFIM） sensorless control, where injection and acting voltages are virtual ones. For computing the whole PMSM model, differential equations are used. The paper is focused on performance analysis of computing speed and accuracy of field-programmable gate array （FPGA） device, digital signal controller and Power PC microcontroller and results are compared.展开更多
In this paper, firstly, a basic nonlinear magnetic network model considering iron saturations is proposed for a three-phase 12-stator-slot/10-rotor-pole flux-switching permanent magnet(FSPM) machine. This model is bui...In this paper, firstly, a basic nonlinear magnetic network model considering iron saturations is proposed for a three-phase 12-stator-slot/10-rotor-pole flux-switching permanent magnet(FSPM) machine. This model is built under cylindrical coordinates and enables the open-circuit air-gap flux-density distributions, phase permanent magnet(PM) flux-linkage, and electromotive-force(EMF) to be predicted with acceptable accuracy. However, large discrepancies are found in the predictions of armature inductances. Then, the basic model is modified by taking into account the localized saturation effect. As a result, the electromagnetic performance can be predicted more accurately, especially for the air-gap flux-density distributions. Furthermore, two improved models are proposed by adding bypass-bridge branches in stator network, to enhance the calculating accuracy of both saturated and unsaturated armature inductances. Finally, the predicted results from the four magnetic network models are validated by both 2D finite element analysis(FEA) and experimental measurements on a machine prototype. Overall, comparisons indicate that the model with bypass-bridge branches between stator teeth and back irons exhibits best performances.展开更多
基金Projects 10172031 supported by National Natural Science Foundation of China and HIT. MD2002.15 by the Multidiscipline Scientific Research Founda-tion of Harbin Institute of Technology
文摘The sealing performance of magnetic fluid is related to the magnetic fluid itself. Many factors can influence the magnetic field and the seal pressure differences of magnetic fluid seals, such as the sealing gap, the shaft eccentricity, the shaft diameter, the volume of the magnetic fluid and the centrifugal force. These factors are analyzed by numerical computation. When the seal material and structure are the same, the seal pressure difference is directly proportional to the magnetic field intensity and the saturation magnetization of the magnetic fluid. The sealing performance of the magnetic fluid will reduce with the increase of the sealing gap and shaft eccentricity. The sealing performance will increase with the volume of the magnetic fluid and decrease with the increase of the shaft diameter taking gravity into account. The increase of the shaft diameter is the same as the reduction of the volume of the magnetic fluid. The magnetic fluid cross-section can change because of the centrifugal force. Some improvements can reducc the influence of the centrifugal force. The centrifugal force can be utilized to improve the sealing performance.
文摘The paper deals with the comparison of three different digital devices used for the computing of permanent magnet synchronous motor （PMSM） model. Model is used for virtual high frequency injection method （VHFIM） sensorless control, where injection and acting voltages are virtual ones. For computing the whole PMSM model, differential equations are used. The paper is focused on performance analysis of computing speed and accuracy of field-programmable gate array （FPGA） device, digital signal controller and Power PC microcontroller and results are compared.
基金supported by the National Basic Research Program of China(“973”Project)(Grant No.2013CB035603)the National Natural Science Foundation of China(Grant Nos.51177013&51322705)+3 种基金Qing Lan Project of Jiangsu ProvinceSix Talents Climax Project of Jiangsu Province(Grant No.2011-ZBZZ-036)Technology R&D Program of Jiangsu Province(Grant Nos.BE2012100&BY2012195)“333 Talents Project”of Jiangsu Province
文摘In this paper, firstly, a basic nonlinear magnetic network model considering iron saturations is proposed for a three-phase 12-stator-slot/10-rotor-pole flux-switching permanent magnet(FSPM) machine. This model is built under cylindrical coordinates and enables the open-circuit air-gap flux-density distributions, phase permanent magnet(PM) flux-linkage, and electromotive-force(EMF) to be predicted with acceptable accuracy. However, large discrepancies are found in the predictions of armature inductances. Then, the basic model is modified by taking into account the localized saturation effect. As a result, the electromagnetic performance can be predicted more accurately, especially for the air-gap flux-density distributions. Furthermore, two improved models are proposed by adding bypass-bridge branches in stator network, to enhance the calculating accuracy of both saturated and unsaturated armature inductances. Finally, the predicted results from the four magnetic network models are validated by both 2D finite element analysis(FEA) and experimental measurements on a machine prototype. Overall, comparisons indicate that the model with bypass-bridge branches between stator teeth and back irons exhibits best performances.
