In order to improve the operation efficiency of coaxial magnetic gear(CMG),in this paper,a CMG model with slotted in magnetic modulation ring is proposed.In this model,the permanent magnets(PMs)of internal and externa...In order to improve the operation efficiency of coaxial magnetic gear(CMG),in this paper,a CMG model with slotted in magnetic modulation ring is proposed.In this model,the permanent magnets(PMs)of internal and external rotors are distributed in Halbach array,the inner rotor PMs are equally divided into 3 small pieces,and the outer rotor PMs are equally divided into 2 small pieces.At the same time,the static magnetic modulation ring iron blocks are slotted,each iron block has 3 slots,the width of the slot is 0.4°,and the depth of the single side slot is 1mm.Finally,a two-dimensional model is established,and the eddy current loss and iron loss of the model are optimized,compared with the conventional CMG model,it is found that the changed pattern can increase the internal and external output torque by 4%and 4.12%,respectively.The eddy current loss is reduced by 66.57%,and the iron loss is reduced by 8.9%,which significantly improve the operation efficiency of the CMG.展开更多
Wind turbine is a key device to realize the utilization of wind energy,and it has been highly valued by all countries.But the mechanical gear transmission of the existing wind power device has the disadvantages of hig...Wind turbine is a key device to realize the utilization of wind energy,and it has been highly valued by all countries.But the mechanical gear transmission of the existing wind power device has the disadvantages of high vibration and noise,high failure rate,and short service time.Magneticfield modulation electromagnetic gear transmission is a new non-contact transmission method.However,the conventional modulation magnetic gear has low torque density and torque defects with largefluctuations.In order to overcome the gear transmis-sion problems of the existing semi-direct drive wind power generation machinery and improve the electromag-netic performance of the traditional magnetic gear transmission,this paper proposes a new transmission scheme of a non-contact semi-direct drive wind generator with a surface mount Halbach array modulated mag-netic gear method,and considers the electromagnetic properties of the semi-direct drive modulation magnetic gear of the wind turbine.Thefinite element software is used to construct the model of the surface-mounted Halbach array magnetic gear and the conventional gear,analyzed the distribution of magneticfield lines of the two magnetic gears,calculated the air gap magneticflux density of the inner and outer air gap,and obtained the main harmonics of the inner and outer air gap magnetic density;calculated the static torque and steady-state operating torque of the inner and outer rotors in the model,compared the air gapflux density,harmonics and torque of the magnetic gears.The simulation results show that the magneticfield modulation type mag-netic gear of the surface mount Halbach array magnetic gear method improves the magnetic induction wave-form of the inner and outer air gap,reduces the pulse torquefluctuation,and has a 60%higher static torque.Applying it to semi-direct drive wind power generation equipment not only overcomes the shortcomings of mechanical gears,but also has higher electromagnetic performance.Therefore,the surface-mounted Halbach array modulated magnetic gear can be used to replace the mechanical gearbox in the semi-direct drive wind power generation equipment.展开更多
A cycloidal speed reducer employing gears with permanent magnets acting as teeth is described. The magnets, which have their axes radially oriented in both the orbiting gear and the fixed internal gear, are inserted i...A cycloidal speed reducer employing gears with permanent magnets acting as teeth is described. The magnets, which have their axes radially oriented in both the orbiting gear and the fixed internal gear, are inserted in holes drilled in nonmagnetic rims without protruding from the cylindrical exposed surfaces. Because the orbiting gear is not restrained radially, it contacts the fixed gear and rolls on its inner surface. A normal force is developed at the contact point between the gears to balance the magnetic attraction and the centrifugal force of the orbiting gear. The friction available due to this normal force increases the transmission’s torque capacity, which is further increased by elimination of the gap between the gears. Also, the radial load on the supporting orbiting gear bearing is eliminated. A prototype with a reduction ratio of 26 is being tested.展开更多
This paper overviews the recent developments and various topologies of magnetically geared(MGd)machines.Particularly,current design trends and research hotspots of this kind of MGd machines are emphasized,with the aid...This paper overviews the recent developments and various topologies of magnetically geared(MGd)machines.Particularly,current design trends and research hotspots of this kind of MGd machines are emphasized,with the aid of statistic summary of the published papers.According to different evolutions from a magnetic gear(MG),four mainstreams of MGd machines are extracted and compared in terms of both mechanical complexity and electromagnetic performance.By virtue of their inherent features,such as high torque density and multi-power port,the feasibility of MGd machines for applications,where continuously variable transmission(CVT)and power split are demanded,is also described.展开更多
In this paper,a performance comparison between the novel axial flux magnetically geared machines(AFMG)and the conventional axial flux YASA machine is presented.The AFMG and YASA machines have the same stator construct...In this paper,a performance comparison between the novel axial flux magnetically geared machines(AFMG)and the conventional axial flux YASA machine is presented.The AFMG and YASA machines have the same stator construction in which segments are equipped with concentrated windings to form the stator.However,the AFMG machine has two rotors with different pole-pair numbers.Magnetic gear effect can be obtained to increase the torque density.The performance comparisons at no-load and on-load conditions are then studied by 3D-finite element analysis(FEM).Moreover,both machines are prototyped,tested and compared.展开更多
Magnetic gear is a transmission device with novel structure.It uses the principle of magnetic field modulation to transmit torque.In view of the magnetic leakage of the magnetic gear in the process of rotation and can...Magnetic gear is a transmission device with novel structure.It uses the principle of magnetic field modulation to transmit torque.In view of the magnetic leakage of the magnetic gear in the process of rotation and cannot be eliminated,a magnetic gear model with auxiliary silicon steel sheet is proposed.Based on the conventional magnetic gear structure,the silicon steel sheet is placed outside the permanent magnet of the outer rotor.The magnetization mode of the outer rotor permanent magnet is tangential magnetization,and the spoke structure is adopted,and the inner rotor PMs is surface mounted and magnetized in the radial magnetization.The improved model is simulated by finite element method under three-dimensional conditions,and the electromagnetic performances of the model are optimized.Compared with the conventional magnetic gear model,the improved model has good performance,which improves the transmission capacity of output torque and reduces torque ripple.It is a great significance to improve the performance of magnetic gear.展开更多
This paper presents a two-dimensional(2D)magnetic equivalent circuit(MEC)model to investigate the magnetic field distribution in the air-gap of an axial-field magnetic gear(AFMG).The MEC model is configured as a meshe...This paper presents a two-dimensional(2D)magnetic equivalent circuit(MEC)model to investigate the magnetic field distribution in the air-gap of an axial-field magnetic gear(AFMG).The MEC model is configured as a meshed reluctance network(RN)with permanent magnet magnetomotive-force sources.The MEC model based on RN is considered as a good compromise between accuracy and computational effort.This is a new model that will allow a faster analysis and design for the AFMG.Flux density in the air-gap is calculated with the proposed model and verified by finite element simulations.展开更多
In mechanical gear systems, dust, noise, vibration, and tooth wear are generated by frictions among gear teeth, and suppressing friction requires lubrication. Magnetic gears transmit torque by magnetic forces without ...In mechanical gear systems, dust, noise, vibration, and tooth wear are generated by frictions among gear teeth, and suppressing friction requires lubrication. Magnetic gears transmit torque by magnetic forces without contact and so avoid contact-related problems. The present paper discusses magnet arrangements and the shape of stationary gear teeth to improve transmission torque in surface magnet type magnetic gear transmission mechanisms.展开更多
The principle and design method of the large gap magnetic drive system is studied in this work. The calculation model of the torque-angle characteristic in the large gap magnetic drive system driven by traveling wave ...The principle and design method of the large gap magnetic drive system is studied in this work. The calculation model of the torque-angle characteristic in the large gap magnetic drive system driven by traveling wave magnetic field is established. The calculation model is computed by using MATLAB software, and the pattern of the system’s torque-angle characteristic is obtained by analyzing study results. These results indicate that: torque-angle characteristic and the driving torque of the system can be adjusted by changing the electric current of coil, the magnetization of permanent magnetic gear, the inner diameter of permanent magnetic gear, the coupling distance between electromagnet and permanent magnetic gear, the outer diameter of permanent magnetic gear, and the axial length of permanent magnetic gear.展开更多
基金supported in part by National Natural Science Foundation of China and China Postdoctoral Science Foundation.(Project No.51707072,2018M632855).
文摘In order to improve the operation efficiency of coaxial magnetic gear(CMG),in this paper,a CMG model with slotted in magnetic modulation ring is proposed.In this model,the permanent magnets(PMs)of internal and external rotors are distributed in Halbach array,the inner rotor PMs are equally divided into 3 small pieces,and the outer rotor PMs are equally divided into 2 small pieces.At the same time,the static magnetic modulation ring iron blocks are slotted,each iron block has 3 slots,the width of the slot is 0.4°,and the depth of the single side slot is 1mm.Finally,a two-dimensional model is established,and the eddy current loss and iron loss of the model are optimized,compared with the conventional CMG model,it is found that the changed pattern can increase the internal and external output torque by 4%and 4.12%,respectively.The eddy current loss is reduced by 66.57%,and the iron loss is reduced by 8.9%,which significantly improve the operation efficiency of the CMG.
基金supported by the National Natural Science Foundation of China(Grant No.51765020)the Natural Science Foundation of Jiangxi Province(Grant No.20161BAB206153).
文摘Wind turbine is a key device to realize the utilization of wind energy,and it has been highly valued by all countries.But the mechanical gear transmission of the existing wind power device has the disadvantages of high vibration and noise,high failure rate,and short service time.Magneticfield modulation electromagnetic gear transmission is a new non-contact transmission method.However,the conventional modulation magnetic gear has low torque density and torque defects with largefluctuations.In order to overcome the gear transmis-sion problems of the existing semi-direct drive wind power generation machinery and improve the electromag-netic performance of the traditional magnetic gear transmission,this paper proposes a new transmission scheme of a non-contact semi-direct drive wind generator with a surface mount Halbach array modulated mag-netic gear method,and considers the electromagnetic properties of the semi-direct drive modulation magnetic gear of the wind turbine.Thefinite element software is used to construct the model of the surface-mounted Halbach array magnetic gear and the conventional gear,analyzed the distribution of magneticfield lines of the two magnetic gears,calculated the air gap magneticflux density of the inner and outer air gap,and obtained the main harmonics of the inner and outer air gap magnetic density;calculated the static torque and steady-state operating torque of the inner and outer rotors in the model,compared the air gapflux density,harmonics and torque of the magnetic gears.The simulation results show that the magneticfield modulation type mag-netic gear of the surface mount Halbach array magnetic gear method improves the magnetic induction wave-form of the inner and outer air gap,reduces the pulse torquefluctuation,and has a 60%higher static torque.Applying it to semi-direct drive wind power generation equipment not only overcomes the shortcomings of mechanical gears,but also has higher electromagnetic performance.Therefore,the surface-mounted Halbach array modulated magnetic gear can be used to replace the mechanical gearbox in the semi-direct drive wind power generation equipment.
文摘A cycloidal speed reducer employing gears with permanent magnets acting as teeth is described. The magnets, which have their axes radially oriented in both the orbiting gear and the fixed internal gear, are inserted in holes drilled in nonmagnetic rims without protruding from the cylindrical exposed surfaces. Because the orbiting gear is not restrained radially, it contacts the fixed gear and rolls on its inner surface. A normal force is developed at the contact point between the gears to balance the magnetic attraction and the centrifugal force of the orbiting gear. The friction available due to this normal force increases the transmission’s torque capacity, which is further increased by elimination of the gap between the gears. Also, the radial load on the supporting orbiting gear bearing is eliminated. A prototype with a reduction ratio of 26 is being tested.
文摘This paper overviews the recent developments and various topologies of magnetically geared(MGd)machines.Particularly,current design trends and research hotspots of this kind of MGd machines are emphasized,with the aid of statistic summary of the published papers.According to different evolutions from a magnetic gear(MG),four mainstreams of MGd machines are extracted and compared in terms of both mechanical complexity and electromagnetic performance.By virtue of their inherent features,such as high torque density and multi-power port,the feasibility of MGd machines for applications,where continuously variable transmission(CVT)and power split are demanded,is also described.
文摘In this paper,a performance comparison between the novel axial flux magnetically geared machines(AFMG)and the conventional axial flux YASA machine is presented.The AFMG and YASA machines have the same stator construction in which segments are equipped with concentrated windings to form the stator.However,the AFMG machine has two rotors with different pole-pair numbers.Magnetic gear effect can be obtained to increase the torque density.The performance comparisons at no-load and on-load conditions are then studied by 3D-finite element analysis(FEM).Moreover,both machines are prototyped,tested and compared.
基金This work was supported in part by National Natural Science Foundation of ChinaChina Postdoctoral Science Foundation.(Project No.51707072,2018M632855)。
文摘Magnetic gear is a transmission device with novel structure.It uses the principle of magnetic field modulation to transmit torque.In view of the magnetic leakage of the magnetic gear in the process of rotation and cannot be eliminated,a magnetic gear model with auxiliary silicon steel sheet is proposed.Based on the conventional magnetic gear structure,the silicon steel sheet is placed outside the permanent magnet of the outer rotor.The magnetization mode of the outer rotor permanent magnet is tangential magnetization,and the spoke structure is adopted,and the inner rotor PMs is surface mounted and magnetized in the radial magnetization.The improved model is simulated by finite element method under three-dimensional conditions,and the electromagnetic performances of the model are optimized.Compared with the conventional magnetic gear model,the improved model has good performance,which improves the transmission capacity of output torque and reduces torque ripple.It is a great significance to improve the performance of magnetic gear.
文摘This paper presents a two-dimensional(2D)magnetic equivalent circuit(MEC)model to investigate the magnetic field distribution in the air-gap of an axial-field magnetic gear(AFMG).The MEC model is configured as a meshed reluctance network(RN)with permanent magnet magnetomotive-force sources.The MEC model based on RN is considered as a good compromise between accuracy and computational effort.This is a new model that will allow a faster analysis and design for the AFMG.Flux density in the air-gap is calculated with the proposed model and verified by finite element simulations.
文摘In mechanical gear systems, dust, noise, vibration, and tooth wear are generated by frictions among gear teeth, and suppressing friction requires lubrication. Magnetic gears transmit torque by magnetic forces without contact and so avoid contact-related problems. The present paper discusses magnet arrangements and the shape of stationary gear teeth to improve transmission torque in surface magnet type magnetic gear transmission mechanisms.
文摘The principle and design method of the large gap magnetic drive system is studied in this work. The calculation model of the torque-angle characteristic in the large gap magnetic drive system driven by traveling wave magnetic field is established. The calculation model is computed by using MATLAB software, and the pattern of the system’s torque-angle characteristic is obtained by analyzing study results. These results indicate that: torque-angle characteristic and the driving torque of the system can be adjusted by changing the electric current of coil, the magnetization of permanent magnetic gear, the inner diameter of permanent magnetic gear, the coupling distance between electromagnet and permanent magnetic gear, the outer diameter of permanent magnetic gear, and the axial length of permanent magnetic gear.