This paper proposes a new consequent-pole permanent magnet vernier machine(CPMVM),which can be regarded as a combination of two conventional CPMVM with opposite polarities.Based on the simplified axial magnetic circui...This paper proposes a new consequent-pole permanent magnet vernier machine(CPMVM),which can be regarded as a combination of two conventional CPMVM with opposite polarities.Based on the simplified axial magnetic circuit model,it is verified that the proposed CPMVM can reduce the unipolar leakage flux.In order to reduce the torque ripple of machine and improve the output torque of machine,the flux barrier is placed on the rotor of the proposed machine.Then,the parameters of the proposed CPMVM are optimized and determined.Moreover,the electromagnetic performance,including no-load air-gap flux density,average torque and torque ripple,flux linkage,back-electromotive force,cogging torque,average torque,torque ripple,power factor and loss,is compared with conventional surface-mounted permanent magnet vernier machine(SPMVM)and CPMVM.Finally,it is demonstrated that proposed CPMVM with flux barrier can effectively reduce the unipolar leakage flux and greatly reduce the torque ripple of machine.Also,compared with the SPMVM,the proposed CPMVM with flux barrier saves more than 45%of the permanent magnet material without reducing output torque.展开更多
A fault-tolerant permanent-magnet vernier(FT-PMV)machine incorporates the merits of high fault-tolerant capability and high torque density.In this paper,a remedial phase-angle control(RPAC)strategy is proposed for a f...A fault-tolerant permanent-magnet vernier(FT-PMV)machine incorporates the merits of high fault-tolerant capability and high torque density.In this paper,a remedial phase-angle control(RPAC)strategy is proposed for a five-phase FT-PMV machine with short-circuit fault.Firstly,the proposed strategy can reduce the amount of unknown quantities by structuring the phase-angles of the normal phases.It can simplify the calculation of the remedial currents.Then,in order to obtain the desired torque,only the amplitudes of the remedial currents need to be calculated.Based on the principle of instantaneous electrical input power and mechanical output power balance condition,the real components are used to maintain the torque capability,while the reactive components are limited zero to minimize the torque ripple.Both simulations and experiments are presented to verify the proposed RPAC strategy.展开更多
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 ...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.展开更多
With the increasing demand for high torque density in motors,more and more new topologies emerge.Furthermore,the magnetic field modulation principle is widely concerned and has evolved into an effective analysis metho...With the increasing demand for high torque density in motors,more and more new topologies emerge.Furthermore,the magnetic field modulation principle is widely concerned and has evolved into an effective analysis method for studying the new motor topology.This paper introduces the principle of magnetic field modulation.And the research on high torque density in recent years is reviewed from the perspective of magnetic field modulation,including permanent magnet vernier machine(PMVM),flux reverse machine(FRM),flux switching machine(FSM),dual permanent magnet(DPM)machine,and DC biased machine.The principle of magnetic field modulation makes it possible to propose higher torque density topologies in the future.展开更多
In this paper,an outer-rotor parallel-hybrid-excited vernier machine is proposed.In order to realize the parallel hybrid excitation,the homopolar configuration is adopted to artfully combine the permanent magnet(PM)fl...In this paper,an outer-rotor parallel-hybrid-excited vernier machine is proposed.In order to realize the parallel hybrid excitation,the homopolar configuration is adopted to artfully combine the permanent magnet(PM)flux path and the electromagnet flux path together.Firstly,the structure of the proposed machine is presented.Secondly,its operating principle is studied and discussed.Thirdly,its performance for flux regulation is analyzed based on the 3-D finite element analysis.Finally,the prototype of the proposed machine is manufactured and tested to verify the analytical results.展开更多
In this paper,a new equivalent magnetic network(EMN)model is established for a spoke-type permanent magnet(PM)vernier(PMV)machine.Two different modeling methods are proposed for different parts of the PMV machine,cons...In this paper,a new equivalent magnetic network(EMN)model is established for a spoke-type permanent magnet(PM)vernier(PMV)machine.Two different modeling methods are proposed for different parts of the PMV machine,considering that their magnetic field distributions are quite different.Hierarchical modeling method is proposed for the modeling of the rotor as the magnetic intensity of the rotor iron core presents gradient distribution along the radial direction.Mesh based reluctance network method is used for the modeling of flux modulation poles with irregular and unstable magnetic field distributions.Moreover,accurate PM leakage permeance calculation formulae are deduced to improve the simulation precision.The electromagnetic parameters,such as flux linkage,back electromagnetic force,electromagnetic torque and iron loss are predicted by the proposed EMN model.Finally,finite element analysis(FEA)and experimental results are given to verify the effectiveness of the proposed methods.展开更多
Offshore wind energy is an important part of clean energy,and the adoption of wind energy to generate electricity will contribute to the implementation of the carbon peaking and carbon neutrality goals.The combination...Offshore wind energy is an important part of clean energy,and the adoption of wind energy to generate electricity will contribute to the implementation of the carbon peaking and carbon neutrality goals.The combination of the fractional frequency transmission system(FFTS) and the direct-drive wind turbine generator will be beneficial to the development of the offshore wind power industry.The use of fractional frequency in FFTS is beneficial to the transmission of electrical energy,but it will also lead to an increase in the volume and weight of the generator,which is unfavorable for wind power generation.Improving the torque density of the generator can effectively reduce the volume of the generators.The vernier permanent magnet machine(VPM) operates on the magnetic flux modulation principle and has the merits of high torque density.In the field of electric machines,the vernier machine based on the principle of magnetic flux modulation has been proved its feasibility to reduce the volume and weight.However,in the field of low-speed direct-drive machines for high-power fractional frequency power generation,there are still few related researches.Therefore,this paper studies the application of magnetic flux modulation in fractional frequency and high-power direct-drive wind turbine generators,mainly analyzes the influence of different pole ratios and different pole pairs on the generator,and draws some conclusions to provide reference for the design of wind turbine generators.展开更多
An analytical solution(ANA)for a fractional-slot double-layer-winding open-slot vernier permanent magnet(VPM)machine with tooth tips is presented.Magnetic vector potential equations are analytically solved using the t...An analytical solution(ANA)for a fractional-slot double-layer-winding open-slot vernier permanent magnet(VPM)machine with tooth tips is presented.Magnetic vector potential equations are analytically solved using the technique of variable separation in four subdomains in a two-dimensional polar coordinate system.Based on the solved magnetic vector potential,the flux density distribution,torque,flux linkage,inductance,electromotive force(EMF)and power factor are analytically developed.An 18-slot/32-rotor-pole prototype is analyzed,and the results match well with the finite element analysis(FEA),which validates that the ANA consumes less time than FEA.Therefore,the tooth tips are optimized using the ANA to improve the average torque.Moreover,the ANA can be used to evaluate the demagnetization withstand capabilities of permanent magnets.The material utilization,slot-filling factor,EMF,and torque are compared between the models with three and four subdomains.Finally,an experimental prototype is constructed and tested,and the results validate the ANA.展开更多
基金supported in part by the National Natural Science Foundation of China under Projects 52177044 and 52025073in part by the China Postdoctoral Science Foundation under Project 2019T120395+3 种基金in part by Hong Kong Scholars Program under Project XJ2019031in part by the Natural Science Foundation of Jiangsu Higher Education Institutions under Project 21KJA470004in part by Qing Lan Project of Jiangsu Provincein part by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘This paper proposes a new consequent-pole permanent magnet vernier machine(CPMVM),which can be regarded as a combination of two conventional CPMVM with opposite polarities.Based on the simplified axial magnetic circuit model,it is verified that the proposed CPMVM can reduce the unipolar leakage flux.In order to reduce the torque ripple of machine and improve the output torque of machine,the flux barrier is placed on the rotor of the proposed machine.Then,the parameters of the proposed CPMVM are optimized and determined.Moreover,the electromagnetic performance,including no-load air-gap flux density,average torque and torque ripple,flux linkage,back-electromotive force,cogging torque,average torque,torque ripple,power factor and loss,is compared with conventional surface-mounted permanent magnet vernier machine(SPMVM)and CPMVM.Finally,it is demonstrated that proposed CPMVM with flux barrier can effectively reduce the unipolar leakage flux and greatly reduce the torque ripple of machine.Also,compared with the SPMVM,the proposed CPMVM with flux barrier saves more than 45%of the permanent magnet material without reducing output torque.
基金This work was supported by the National Natural Science Foundation of China(51422702)by the by the Qing Lan Project,and by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘A fault-tolerant permanent-magnet vernier(FT-PMV)machine incorporates the merits of high fault-tolerant capability and high torque density.In this paper,a remedial phase-angle control(RPAC)strategy is proposed for a five-phase FT-PMV machine with short-circuit fault.Firstly,the proposed strategy can reduce the amount of unknown quantities by structuring the phase-angles of the normal phases.It can simplify the calculation of the remedial currents.Then,in order to obtain the desired torque,only the amplitudes of the remedial currents need to be calculated.Based on the principle of instantaneous electrical input power and mechanical output power balance condition,the real components are used to maintain the torque capability,while the reactive components are limited zero to minimize the torque ripple.Both simulations and experiments are presented to verify the proposed RPAC strategy.
基金Supported by the National Natural Science Foundation of China under Grant 52025073the Natural Science Foundation of Jiangsu Province under Grant BK20210770.
文摘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.
基金supported in part by the National Natural Science Foundation of China(NSFC)under Project No.51737010the National Key R&D Program of China under Grant 2020YFA0710500。
文摘With the increasing demand for high torque density in motors,more and more new topologies emerge.Furthermore,the magnetic field modulation principle is widely concerned and has evolved into an effective analysis method for studying the new motor topology.This paper introduces the principle of magnetic field modulation.And the research on high torque density in recent years is reviewed from the perspective of magnetic field modulation,including permanent magnet vernier machine(PMVM),flux reverse machine(FRM),flux switching machine(FSM),dual permanent magnet(DPM)machine,and DC biased machine.The principle of magnetic field modulation makes it possible to propose higher torque density topologies in the future.
基金Supported in part by the National Natural Science Foundation of China under Grant 51607114in part by China Postdoctoral Science Foundation under Grant 2016M600673in part by Research Council of the University of Macao under Grant MYRG2017-00158-FST.
文摘In this paper,an outer-rotor parallel-hybrid-excited vernier machine is proposed.In order to realize the parallel hybrid excitation,the homopolar configuration is adopted to artfully combine the permanent magnet(PM)flux path and the electromagnet flux path together.Firstly,the structure of the proposed machine is presented.Secondly,its operating principle is studied and discussed.Thirdly,its performance for flux regulation is analyzed based on the 3-D finite element analysis.Finally,the prototype of the proposed machine is manufactured and tested to verify the analytical results.
基金Supported by National Natural Science Foundation of China under Grant 51577084Key Project of Natural Science Foundation of Jiangsu Higher Education Institutions under Grant 15KJA470002the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘In this paper,a new equivalent magnetic network(EMN)model is established for a spoke-type permanent magnet(PM)vernier(PMV)machine.Two different modeling methods are proposed for different parts of the PMV machine,considering that their magnetic field distributions are quite different.Hierarchical modeling method is proposed for the modeling of the rotor as the magnetic intensity of the rotor iron core presents gradient distribution along the radial direction.Mesh based reluctance network method is used for the modeling of flux modulation poles with irregular and unstable magnetic field distributions.Moreover,accurate PM leakage permeance calculation formulae are deduced to improve the simulation precision.The electromagnetic parameters,such as flux linkage,back electromagnetic force,electromagnetic torque and iron loss are predicted by the proposed EMN model.Finally,finite element analysis(FEA)and experimental results are given to verify the effectiveness of the proposed methods.
基金supported by the Science and Technology Foundation of SGCC (5500-202099509A-0-0-00)“Research on Fractional Frequency Transmission Technology for Largely Enhancing Transmission Capacity and Development of Its Key Devices”。
文摘Offshore wind energy is an important part of clean energy,and the adoption of wind energy to generate electricity will contribute to the implementation of the carbon peaking and carbon neutrality goals.The combination of the fractional frequency transmission system(FFTS) and the direct-drive wind turbine generator will be beneficial to the development of the offshore wind power industry.The use of fractional frequency in FFTS is beneficial to the transmission of electrical energy,but it will also lead to an increase in the volume and weight of the generator,which is unfavorable for wind power generation.Improving the torque density of the generator can effectively reduce the volume of the generators.The vernier permanent magnet machine(VPM) operates on the magnetic flux modulation principle and has the merits of high torque density.In the field of electric machines,the vernier machine based on the principle of magnetic flux modulation has been proved its feasibility to reduce the volume and weight.However,in the field of low-speed direct-drive machines for high-power fractional frequency power generation,there are still few related researches.Therefore,this paper studies the application of magnetic flux modulation in fractional frequency and high-power direct-drive wind turbine generators,mainly analyzes the influence of different pole ratios and different pole pairs on the generator,and draws some conclusions to provide reference for the design of wind turbine generators.
文摘An analytical solution(ANA)for a fractional-slot double-layer-winding open-slot vernier permanent magnet(VPM)machine with tooth tips is presented.Magnetic vector potential equations are analytically solved using the technique of variable separation in four subdomains in a two-dimensional polar coordinate system.Based on the solved magnetic vector potential,the flux density distribution,torque,flux linkage,inductance,electromotive force(EMF)and power factor are analytically developed.An 18-slot/32-rotor-pole prototype is analyzed,and the results match well with the finite element analysis(FEA),which validates that the ANA consumes less time than FEA.Therefore,the tooth tips are optimized using the ANA to improve the average torque.Moreover,the ANA can be used to evaluate the demagnetization withstand capabilities of permanent magnets.The material utilization,slot-filling factor,EMF,and torque are compared between the models with three and four subdomains.Finally,an experimental prototype is constructed and tested,and the results validate the ANA.