Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8506780
K. Khan, F. Gyllensten
This paper deals with bearing currents phenomena in general and specifically for capacitive bearing currents in low voltage motors. With the technological advances in the automation field, new problems have also surfaced and bearing currents in small motors is one of such issues. It is important to investigate root-cause and distinguish these relatively new currents from already known and addressed bearing current types. In an effort to accomplish this task, this paper presents extensive measurement results of different variable speed drives systems and bearing lubrication types. Measurement results analysis indicate that bearing current damage can be minimized or avoided by selecting the right operating conditions, lubrication and right installation practices. Furthermore, mitigation solutions for different root causes are proposed and evaluated though measurements.
{"title":"Experimental Investigation of Bearing Currents in Low Voltage Motors","authors":"K. Khan, F. Gyllensten","doi":"10.1109/ICELMACH.2018.8506780","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8506780","url":null,"abstract":"This paper deals with bearing currents phenomena in general and specifically for capacitive bearing currents in low voltage motors. With the technological advances in the automation field, new problems have also surfaced and bearing currents in small motors is one of such issues. It is important to investigate root-cause and distinguish these relatively new currents from already known and addressed bearing current types. In an effort to accomplish this task, this paper presents extensive measurement results of different variable speed drives systems and bearing lubrication types. Measurement results analysis indicate that bearing current damage can be minimized or avoided by selecting the right operating conditions, lubrication and right installation practices. Furthermore, mitigation solutions for different root causes are proposed and evaluated though measurements.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124190547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8506810
E. Engevik, M. Valavi, A. Nysveen
This paper investigates the effect of converter operation on AC copper losses in the stator and damper windings of a large hydrogenerator. Stator currents are computed using finite element simulations. The computed current waveforms are used as an input to estimate the AC copper losses in the stator due to converter operation using an analytical approach. Damperbar losses are calculated directly in the finite element analysis. The generator is simulated with a two-level voltage source converter and a three-level neutral-point-clamped converter topology. Different carrier frequencies are used to investigate their effect on the AC copper loss. Methods for handling these additional losses are discussed and analysed.
{"title":"Analysis of Additional Eddy-Current Copper Losses in Large Converter-Fed Hydropower Generators","authors":"E. Engevik, M. Valavi, A. Nysveen","doi":"10.1109/ICELMACH.2018.8506810","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8506810","url":null,"abstract":"This paper investigates the effect of converter operation on AC copper losses in the stator and damper windings of a large hydrogenerator. Stator currents are computed using finite element simulations. The computed current waveforms are used as an input to estimate the AC copper losses in the stator due to converter operation using an analytical approach. Damperbar losses are calculated directly in the finite element analysis. The generator is simulated with a two-level voltage source converter and a three-level neutral-point-clamped converter topology. Different carrier frequencies are used to investigate their effect on the AC copper loss. Methods for handling these additional losses are discussed and analysed.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"324 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116825749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8506846
Z. Zeng, Jiawen Zhan, Q. Lu
To overcome the demerits of conventional hybrid-excited flux-switching linear machine (HEFSLM), a novel dual-PM partitioned-primary HEFSLM (dual-PM PP-HEFSLM) has been proposed and investigated with merits of high thrust force density, improved space utilization, flexible flux control and robust secondary. To this novel dual-PM PP-HEFSLM, this paper investigates its dynamic performance with a primary-flux-oriented (PFO) vector control strategy. Firstly, the d-q mathematical model of the proposed machine has been derived. Then, the proposed PFO vector control strategy is presented in detail. Finally, the proposed control schemes are validated through MATLAB/Simulink simulation. The simulation results shows that the proposed machine exhibits good dynamic performance by adoption of the PFO vector control strategy.
{"title":"Dynamic Performance of Dual-PM Partitioned-primary Hybrid-excited Flux-switching Linear Machine","authors":"Z. Zeng, Jiawen Zhan, Q. Lu","doi":"10.1109/ICELMACH.2018.8506846","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8506846","url":null,"abstract":"To overcome the demerits of conventional hybrid-excited flux-switching linear machine (HEFSLM), a novel dual-PM partitioned-primary HEFSLM (dual-PM PP-HEFSLM) has been proposed and investigated with merits of high thrust force density, improved space utilization, flexible flux control and robust secondary. To this novel dual-PM PP-HEFSLM, this paper investigates its dynamic performance with a primary-flux-oriented (PFO) vector control strategy. Firstly, the d-q mathematical model of the proposed machine has been derived. Then, the proposed PFO vector control strategy is presented in detail. Finally, the proposed control schemes are validated through MATLAB/Simulink simulation. The simulation results shows that the proposed machine exhibits good dynamic performance by adoption of the PFO vector control strategy.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116413382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8507197
Unai Galfarsoro, A. McCloskey, G. Almandoz, Xabier Hernández, X. Arrasate
In order to optimize key aspects of the performance of electrical machines, all the design features need to be analyzed. The study is focused on the influence of the teeth tip geometries of Permanent Magnet Synchronous Motors. Open slots and semi-closed slots are considered, and the performances are evaluated measuring the electromotive forces induced in several search coils inserted inside the slots. This analysis is done experimentally by means of an innovative test bench where small pieces manufactured like the stator with different teeth geometries can be inserted and interchanged easily and economically, without the need to build an entire stator each time. Semi-closed slots generate bigger back-EMF amplitudes than open slots, but both generate frequency harmonics of similar amplitudes, so semi-closed slots show a better performance. This experimental test bench is also used to verify the FE electromagnetic simulation models; the correlation with measurements shows good agreement.
{"title":"Stator Teeth Tips Shape Influence in Permanent Magnet Synchronous Motors on a Test Bench","authors":"Unai Galfarsoro, A. McCloskey, G. Almandoz, Xabier Hernández, X. Arrasate","doi":"10.1109/ICELMACH.2018.8507197","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8507197","url":null,"abstract":"In order to optimize key aspects of the performance of electrical machines, all the design features need to be analyzed. The study is focused on the influence of the teeth tip geometries of Permanent Magnet Synchronous Motors. Open slots and semi-closed slots are considered, and the performances are evaluated measuring the electromotive forces induced in several search coils inserted inside the slots. This analysis is done experimentally by means of an innovative test bench where small pieces manufactured like the stator with different teeth geometries can be inserted and interchanged easily and economically, without the need to build an entire stator each time. Semi-closed slots generate bigger back-EMF amplitudes than open slots, but both generate frequency harmonics of similar amplitudes, so semi-closed slots show a better performance. This experimental test bench is also used to verify the FE electromagnetic simulation models; the correlation with measurements shows good agreement.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"27 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123214894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8507212
J. K. NØland, M. Giset, E. Alves
Field-wound synchronous machines represent the majority of large power generating units and special high-power motor solutions, because they offer high efficiency, flexible field excitation and deep flux weakening capability. In this contribution, we present a comprehensive survey of the modern approaches of excitation systems for synchronous machines. Specifically, the fundamental theory, typical de-excitation methods and excitation equipment topologies. Finally, we describe the latest trends in static, brushless and harmonic exciters, current challenges and future opportunities.
{"title":"Continuous Evolution and Modern Approaches of Excitation Systems for Synchronous Machines","authors":"J. K. NØland, M. Giset, E. Alves","doi":"10.1109/ICELMACH.2018.8507212","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8507212","url":null,"abstract":"Field-wound synchronous machines represent the majority of large power generating units and special high-power motor solutions, because they offer high efficiency, flexible field excitation and deep flux weakening capability. In this contribution, we present a comprehensive survey of the modern approaches of excitation systems for synchronous machines. Specifically, the fundamental theory, typical de-excitation methods and excitation equipment topologies. Finally, we describe the latest trends in static, brushless and harmonic exciters, current challenges and future opportunities.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122143659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8507243
Sven Exnowski, M. Humer
Because of the energy recovery and other technical and economic changes, high-voltage direct-current transmission is to be increasingly used in the nourishing future. The required inverter stations cause subsynchronous frequencies in the three-phase system near the connection point. These may possibly be close to mechanical subsynchronous torsional natural frequencies of large turbosets. The excitation of subsynchronous resonances in power stations means a serious risk for the shaft train. In order to be able to assess the risk for a shaft train in advance, the calculation of the occurring moments as well as the resulting fatigue due to such an excitation is usually required on the basis of detailed models. In addition, less complex models which are used in the analysis of larger networks can be derived from these detailed models.
{"title":"Subsynchronous Resonances in the Shaft Train of Large Turbosets and High Voltage DC Transmission","authors":"Sven Exnowski, M. Humer","doi":"10.1109/ICELMACH.2018.8507243","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8507243","url":null,"abstract":"Because of the energy recovery and other technical and economic changes, high-voltage direct-current transmission is to be increasingly used in the nourishing future. The required inverter stations cause subsynchronous frequencies in the three-phase system near the connection point. These may possibly be close to mechanical subsynchronous torsional natural frequencies of large turbosets. The excitation of subsynchronous resonances in power stations means a serious risk for the shaft train. In order to be able to assess the risk for a shaft train in advance, the calculation of the occurring moments as well as the resulting fatigue due to such an excitation is usually required on the basis of detailed models. In addition, less complex models which are used in the analysis of larger networks can be derived from these detailed models.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123946303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8507082
Gayan Watthewaduge, M. Toulabi, S. Filizadeh
In this paper, the effects of core saturation and machine's losses are considered to predict the performance of a conventional single inverter and a dual inverter open winding Interior Permanent Magnet Synchronous Motor (IPMSM) drive in Maximum Torque per Ampere (MTPA) and Field Weakening (FW) regions using Finite Element Analysis (FEA). It is shown how core saturation, which is a direct function of machine's loading, affects the d- and q-axis inductances and saliency ratio, and the losses including core, solid (due to skin and proximity effects), and mechanical losses significantly change in various operating points and may affect the operating capability of the machine in different drive configurations.
{"title":"Performance Prediction of a Dual Inverter Open Winding IPMSM Drive Considering Machine's Saturation and Losses","authors":"Gayan Watthewaduge, M. Toulabi, S. Filizadeh","doi":"10.1109/ICELMACH.2018.8507082","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8507082","url":null,"abstract":"In this paper, the effects of core saturation and machine's losses are considered to predict the performance of a conventional single inverter and a dual inverter open winding Interior Permanent Magnet Synchronous Motor (IPMSM) drive in Maximum Torque per Ampere (MTPA) and Field Weakening (FW) regions using Finite Element Analysis (FEA). It is shown how core saturation, which is a direct function of machine's loading, affects the d- and q-axis inductances and saliency ratio, and the losses including core, solid (due to skin and proximity effects), and mechanical losses significantly change in various operating points and may affect the operating capability of the machine in different drive configurations.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129701515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8506869
Zi-Qiang Zhu, H. Yang, S. Cai, H. Y. Li, Y. Liu, J. Mipo, S. Personnaz
In this paper, the overlapping winding (OW), i.e. the coil pitches of field and armature windings equal 3 slot pitches (F3A3), is proposed and applied to 12-slot/17-rotor pole (12s17r) hybrid excited stator slot permanent magnet machines (HESSPMs) in order to enhance the torque density. The influence of stator/rotor pole number combinations on the HESSPMs with both non-overlapping winding (NOW) and OW is considered and analyzed. The 12s17r HESSPMs with NOW and OW are selected from the candidates in 12-stator machines for high average torque and low torque ripple under the same copper loss. Their electromagnetic performance is comparatively studied. By adopting OW, it shows that the proposed 12s17r-F3A3 HESSPM improves the fundamental value of the phase back-EMF by 125% than the 12s17r-F1A1. Consequently, the torque density in 12s17r-F1A1 HESSPM have been improved by 100.24% in F3A3 HESSPM.
{"title":"Hybrid Excited Stator Slot PM Machines with Overlapping Windings","authors":"Zi-Qiang Zhu, H. Yang, S. Cai, H. Y. Li, Y. Liu, J. Mipo, S. Personnaz","doi":"10.1109/ICELMACH.2018.8506869","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8506869","url":null,"abstract":"In this paper, the overlapping winding (OW), i.e. the coil pitches of field and armature windings equal 3 slot pitches (F3A3), is proposed and applied to 12-slot/17-rotor pole (12s17r) hybrid excited stator slot permanent magnet machines (HESSPMs) in order to enhance the torque density. The influence of stator/rotor pole number combinations on the HESSPMs with both non-overlapping winding (NOW) and OW is considered and analyzed. The 12s17r HESSPMs with NOW and OW are selected from the candidates in 12-stator machines for high average torque and low torque ripple under the same copper loss. Their electromagnetic performance is comparatively studied. By adopting OW, it shows that the proposed 12s17r-F3A3 HESSPM improves the fundamental value of the phase back-EMF by 125% than the 12s17r-F1A1. Consequently, the torque density in 12s17r-F1A1 HESSPM have been improved by 100.24% in F3A3 HESSPM.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128392659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8506870
M. J. Islam, R. Moghaddam
Influence of the magnetic slot wedge and semiclosed stator slot is studied. The study focuses on the air-gap flux density fluctuation due to the permeance harmonics and associated rotor losses of the machine. Both, the no-load and nominal load simulations are performed for the geometry with non-magnetic slot wedge, with ferrite based magnetic slot wedge and semi-closed slot geometry. The semi-closed stator slot geometry in the field wounded synchronous machine has remarkable influence to reduce the permeance harmonics and as a consequence, the rotor surface and damper bar (DB) losses of the machine. The air-gap length is studied to minimize the total loss of the machine. Variation of the rotor core, damper bar and field winding losses and root causes of these variations are investigated. The study is performed by 2D time discretized finite-element analysis (FEA).
{"title":"Loss Reduction in a Salient Pole Synchronous Machine Due to Magnetic Slot Wedge and Semiclosed Stator Slots","authors":"M. J. Islam, R. Moghaddam","doi":"10.1109/ICELMACH.2018.8506870","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8506870","url":null,"abstract":"Influence of the magnetic slot wedge and semiclosed stator slot is studied. The study focuses on the air-gap flux density fluctuation due to the permeance harmonics and associated rotor losses of the machine. Both, the no-load and nominal load simulations are performed for the geometry with non-magnetic slot wedge, with ferrite based magnetic slot wedge and semi-closed slot geometry. The semi-closed stator slot geometry in the field wounded synchronous machine has remarkable influence to reduce the permeance harmonics and as a consequence, the rotor surface and damper bar (DB) losses of the machine. The air-gap length is studied to minimize the total loss of the machine. Variation of the rotor core, damper bar and field winding losses and root causes of these variations are investigated. The study is performed by 2D time discretized finite-element analysis (FEA).","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130067090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/ICELMACH.2018.8506959
N. Niguchi, K. Hirata, A. Kohara, K. Takahara, H. Suzuki
A current superimposition variable flux reluctance motor for a traction motor of electric vehicles and hybrid electric vehicles are proposed. This motor can be driven using a 6-phase asymmetric inverter which is used to drive a switched reluctance motor. However, it is difficult to obtain a high efficiency in a low-speed and high-torque region. In order to solve this problem, a switching operation between the current superimposition variable flux reluctance motor and a switched reluctance motor is proposed in this paper.
{"title":"Hybrid Drive of a Variable Flux Reluctance Motor and Switched Reluctance Motor","authors":"N. Niguchi, K. Hirata, A. Kohara, K. Takahara, H. Suzuki","doi":"10.1109/ICELMACH.2018.8506959","DOIUrl":"https://doi.org/10.1109/ICELMACH.2018.8506959","url":null,"abstract":"A current superimposition variable flux reluctance motor for a traction motor of electric vehicles and hybrid electric vehicles are proposed. This motor can be driven using a 6-phase asymmetric inverter which is used to drive a switched reluctance motor. However, it is difficult to obtain a high efficiency in a low-speed and high-torque region. In order to solve this problem, a switching operation between the current superimposition variable flux reluctance motor and a switched reluctance motor is proposed in this paper.","PeriodicalId":292261,"journal":{"name":"2018 XIII International Conference on Electrical Machines (ICEM)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128922616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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