The Experts below are selected from a list of 4536 Experts worldwide ranked by ideXlab platform
Z Q Zhu - One of the best experts on this subject based on the ideXlab platform.
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analysis and suppression of induced voltage pulsation in dc winding of five phase wound field switched flux machines
IEEE Transactions on Energy Conversion, 2019Co-Authors: Z Q Zhu, Wei Hua, Sam Akehurst, Xiaofeng Zhu, Wentao Zhang, Junming ZhuAbstract:In wound-field (WF) switched flux (SF) (WFSF) machines, the DC winding induced voltage pulsation causes current ripple in the DC winding and challenges the DC power source, and deteriorates the control performance. In this paper, the induced voltage pulsation in DC winding of five-phase WFSF machines is analyzed and its reduction methods are proposed. The cycles per electric period of the open-circuit and armature reaction induced voltage pulsation in DC winding are derived analytically. Modifying the airgap permeance by optimizing the rotor Pole arc or chamfering the rotor Pole surface, and axial pairing of rotor segments having rotor Pole with different arcs are used to suppress the induced voltage pulsation in DC winding, with >90% average torque maintained. Finite element results show that, by optimizing the rotor Pole arc, the peak-to-peak value of the induced voltage pulsation in DC winding can be effectively suppressed to 59.59%, 30.67%, 29.99% and 43.35% for the 10-Stator-Pole five-phase WFSF machines with 8-, 9-, 11- and 12-rotor-Pole rotors, respectively. By applying rotor Pole surface shaping, the induced voltage pulsation in DC winding peak-to-peak value can be effectively suppressed to 61.76%, 45.47% and 40.21% for the 8-, 9- and 12-rotor-Pole machines, respectively, while by applying axial pairing, it can be suppressed to 46.89%, 7.16%, 15.64% and 12.04%, respectively. The 10-Stator-Pole/12-rotor-Pole WFSF machines having the original rotor, optimized rotor, chamfered rotor and axial paired rotor are prototyped and the experiments validate the analytical and finite element results.
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influence of Stator and rotor Pole number combinations on the electromagnetic performance of Stator slot opening pm hybrid excited machine
IEEE Transactions on Magnetics, 2019Co-Authors: M Zheng, Z Q Zhu, Shun Cai, Yue LiuAbstract:A new type of three-phase Stator hybrid excited machine with permanent magnets (PMs) located at the slot openings of field winding slots is presented in this paper. It has the advantage of good flux regulation capability due to the field excitation. The machines with different Stator/rotor Pole combinations, i.e., 6-Stator Pole and 7-/8-/10-/11-/13-/14-rotor Poles, have been comparatively investigated in terms of the open-circuit and on-load characteristics, as well as the influence of dc current and the unbalanced magnetic forces. The 2-D finite element analysis (FEA) has been employed for analysis and optimization of the machines together with experimental validation.
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reduction of open circuit dc winding induced voltage in wound field switched flux machines by skewing
IEEE Transactions on Industrial Electronics, 2019Co-Authors: Z Q Zhu, C Wang, J C Mipo, Sophie Personnaz, P FarahAbstract:In this paper, the open-circuit dc-winding-induced voltage in a wound field switched flux (WFSFs) machines is analyzed. The phenomenon of open-circuit dc-winding-induced voltage is illustrated and the mechanism is explained. Rotor skewing is proposed to reduce the open-circuit dc-winding-induced voltage, and the optimal skewing angle is analytically derived based on the analytically deduced harmonic orders of the open-circuit dc-winding-induced voltage. Finite-element (FE) analyses show that the open-circuit dc-winding-induced voltages in the analyzed 12-Stator-Pole partitioned Stator WFSF machines having 10-, 11-, 13-, and 14-rotor-Pole rotors can be effectively reduced by >94%, while the ac-winding phase-fundamental back-EMFs can be maintained by >95%. Twelve/ten-Stator/rotor-Pole prototypes with skewed and nonskewed rotors are built and tested to verify the analytical and FE results.
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influence of rotor Pole number on electromagnetic performance in 12 phase redundant switched flux permanent magnet machines for wind power generation
IEEE Transactions on Industry Applications, 2017Co-Authors: Lingyun Shao, Wei Hua, Z Q Zhu, Minghao Tong, Guishu Zhao, Fangbo Yin, Ming ChengAbstract:In this paper, electromagnetic performances of 12-phase 24-Stator-Pole redundant switched flux permanent magnet (SFPM) machines with 20-, 22-, 26-, and 28-rotor-Pole rotors designed for wind power generation are comparatively analyzed. The influence of key design parameters on the open-circuit phase electromotive force and cogging torque is comparatively evaluated by a 2-D finite-element analysis (FEA). FEA results show that the 24-/26-Pole SFPM machine exhibits the highest electromagnetic torque and efficiency than the other three, while the 24-/22-Pole one has the smallest cogging torque and torque ripple as well as relatively good voltage regulation and efficiency, which are essential for a wind generator. Furthermore, the investigation on redundancy performance shows that cross coupling among the four sets of three-phase balanced windings and the saturation effect can be neglected when the generator operates with relative light loads. Finally, the 12-phase 24-/22-Pole SFPM machine is built and tested to validate the simulations.
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partitioned Stator flux reversal machine with consequent Pole pm Stator
IEEE Transactions on Energy Conversion, 2015Co-Authors: Z Q ZhuAbstract:In this paper, partitioned Stator flux reversal permanent magnet (PS-FRPM) machines having different Stator/rotor Pole combinations with consequent-Pole PM (CPM) Stator are proposed and analyzed. Compared with the conventional 12-Stator-Pole PS-FRPM machines having 10-, 11-, 13-, and 14-rotor-Pole rotors and surface-mounted PM (SPM) Stator, the PM volume in the proposed PS-FRPM machines with CPM Stator can be saved by 28.33%, 30%, 30%, and 33.33%, respectively, while the torque density are similar, i.e., 98.59%, 96.69%, 95.50%, and 97.15%, respectively. Besides, the proposed PS-FRPM machines with CPM Stator can exhibit only <1% smaller efficiency compared with the existing PS-FRPM machines with SPM inner Stator.
Zi-qiang Zhu - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Asymmetric Consequent-Pole Hybrid Excited Flux Reversal Machines
2020 IEEE Energy Conversion Congress and Exposition (ECCE), 2020Co-Authors: F. R. Wei, Zi-qiang Zhu, X. Y. SunAbstract:This paper proposes and investigates two asymmetric consequent-Pole hybrid excited flux reversal machine (AS-CP-HEFRM) topologies, which have same numbers of iron Poles and permanent magnets (PMs) with concentrated AC and DC windings on each Stator Pole and a salient Pole rotor. If PM number on one Stator Pole is larger than 1, PMs are magnetized radially in the same direction on one Stator Pole, while opposite on adjacent Stator Poles. The phenomenon and elimination of the phase shift between the flux linkages of DC and PM excitations in the AS-CP-HEFRMs are highlighted and verified by finite element analysis. Meanwhile, the relationship between the rotor Pole number and the Stator Pole arc (PM ratio) is derived for maximum average torque and verified by global optimization. The influence of Stator/rotor Pole number combinations is also studied and compared in terms of torque, torque ripple, and flux regulation capability.
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Design and Analysis of Novel Asymmetric-Stator-Pole Flux Reversal PM Machine
IEEE Transactions on Industrial Electronics, 2020Co-Authors: Hui Yang, Zi-qiang Zhu, Heyun Lin, Shukang Lyu, Liu YangyangAbstract:This paper proposes a novel flux reversal permanent magnet (FRPM) machine with asymmetric-Stator-Pole (ASP) configuration. Different from the conventional FRPM machine with uniform “NS-NS-NS” PM sequence, the proposed ASP-FRPM machine is characterized by a “NSN-S-NSN” magnet arrangement. Hence, the interpolar flux leakage is significantly reduced with the developed design, which can improve the torque capability. The machine topologies, features, and operating principle are introduced, respectively. A simplified magnetic circuit model is established to reveal the underlying flux leakage reduction mechanism of the ASP design, and the rotor Pole number is analytically optimized as well. The design parameters are then globally optimized so as to improve the torque quality. In addition, the electromagnetic characteristics of the ASP- and conventional FRPM machines are compared. Finally, experiments have been carried out to validate the theoretical results.
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Analysis of power factor in variable flux reluctance machines with MMF-permeance model
IET Electric Power Applications, 2019Co-Authors: Liren Huang, Jianghua Feng, Shuying Guo, Junxu Shi, Zi-qiang ZhuAbstract:This study investigates the underlying mechanism of low-power factor issue of variable flux reluctance machines (VFRMs) from the perspective of magneto-motive force (MMF)-permeance model. On the basis of a simplified analytical model, the relationship between the design parameters and the power factor is identified and systematically summarised into three predictable ratios: the rotor permeance ratio, Stator/rotor-Pole ratio and DC/AC winding ampere turns ratio. Specifically, the smaller the rotor-Pole arc, the air-gap length, the rotor-Pole number and the AC/DC winding ampere turns ratio are, the higher the power factor will be. In addition, the weak coupling between the field and armature windings caused by the modulation effect of the salient rotor is responsible for the low-power factor issue of VFRMs, regardless of the control scheme, winding configuration or saturation effect. A 6-Stator-Pole/4-rotor-Pole VFRM is prototyped and tested for verification.
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Comparative study of synchronous machines having permanent magnets in Stator
Electric Power Systems Research, 2016Co-Authors: J T Shi, Zi-qiang Zhu, Xiaoyuan LiuAbstract:Abstract Stator permanent magnet synchronous machines (SPMSMs) with doubly salient Stator and rotor structure and non-overlapping winding are investigated in this paper. The PMs can be located on the surface or in the Stator Pole and even in the Stator yoke with alternative polarities. The selection of rotor Pole number is flexible, which can be any integers except the phase number and its multiples. When the numbers of Stator and rotor Poles ( N s / N r ) are differed by one, 6-Stator Pole SPMSMs have bipolar phase flux-linkages and symmetric phase back-EMFs as well as high torques. Further, three typical PM locations are chosen to compare and analyze the influence of PM locations on electromagnetic performances under 6/7 N s / N r combination. The results show that SPMSM with PMs mounted on the surface of Stator Pole has the highest PM utilization efficiency and the most sinusoidal phase back-EMF but the largest cogging torque. The SPMSM with PMs mounted on the Stator yoke exhibits the largest average torque as well as the lowest torque ripple and cogging torque but the lowest PM utilization efficiency. The analyses are experimentally validated on several prototype machines.
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analysis of novel multi tooth variable flux reluctance machines with different Stator and rotor Pole combinations
IEEE Transactions on Magnetics, 2015Co-Authors: J T Shi, Zi-qiang ZhuAbstract:Novel multi-tooth variable flux reluctance machines (VFRMs), which adopt doubly salient Stator and rotor structure with nonoverlapping Stator ac armature and dc field windings, are investigated in this paper. The rotor Pole number can be any integer except the phase number and its multiples. Meanwhile, to obtain symmetrical bipolar phase flux-linkage and back electromotive force waveforms, the ratio of Stator Pole number to the greatest common divisor of Stator- and rotor-Pole numbers should be even integers. Furthermore, under the same rated copper loss and Stator outer radius as well as 6-Pole Stator, 4-tooth per Stator Pole VFRMs in which the Stator and rotor Pole number determined by N r = nN s ± 1 (n is the number of small teeth per Stator Pole) exhibit the highest average torque. Moreover, compared with the optimal 6/7 Stator/rotor Pole single-tooth VFRM, the 6/25 Stator/rotor Pole 4-tooth VFRM has more sinusoidal and larger back EMF, negligible cogging torque, lower torque ripple, and higher torque capability at relatively low copper loss. Similar to single-tooth VFRMs, 4-tooth VFRMs with N r = nN s ± 1 exhibit more sinusoidal back EMF and larger torque than that of VFRMs with N r = nN s ± 2. The analyses are experimentally validated by several prototype machines.
Jinwoo Ahn - One of the best experts on this subject based on the ideXlab platform.
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Analysis and control of a novel bearingless switched reluctance motor with hybrid Stator Poles
2013 IEEE International Conference on Industrial Technology (ICIT), 2013Co-Authors: Donghee Lee, Jinwoo AhnAbstract:In this paper, a novel bearingless switched reluctance motor (BLSRM) with hybrid Stator Poles is proposed. The proposed BLSRM has short flux path and no flux reversal characteristics, and separated torque and suspending force control. The characteristics of the proposed structure are analyzed by finite element method. The analysis results show that the torque control can be decoupled from the suspending force control and the output torque is significantly improved when compared to the 8/10 hybrid Stator Pole type BLSRM. To verify the validity of the proposed structure, a prototype of the proposed BLSRM is designed and manufactured. Meanwhile, a control scheme is proposed based on the novel structure. In the scheme, a simple PID and hysteresis current control methods are employed. The validity of the proposed structure and its control scheme are verified by the experimental results.
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Suspending force control of a novel 12/14 hybrid Stator Pole type bearingless SRM
2012Co-Authors: Donghee Lee, Jinwoo AhnAbstract:A novel 12/14 hybrid Stator Pole type bearingless switched reluctance motor (BLSRM) is presented. The novel BLSRM has separated torque and suspending force Poles, so the toque control can be naturally decoupled from the suspending force control. In order to verify the proposed BLSRM, based on the novel structure, a control scheme is proposed. According to the proposed control scheme, experimental system is constructed and experiments are performed. The experimental results show that the motor can operate steadily and the torque control can be decoupled from the suspending force control, which verifies the validity of the proposed structure and its control scheme.
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suspending force control of a novel 12 14 hybrid Stator Pole type bearingless srm
International Conference on Electrical Machines and Systems, 2012Co-Authors: Donghee Lee, Jinwoo AhnAbstract:A novel 12/14 hybrid Stator Pole type bearingless switched reluctance motor (BLSRM) is presented. The novel BLSRM has separated torque and suspending force Poles, so the toque control can be naturally decoupled from the suspending force control. In order to verify the proposed BLSRM, based on the novel structure, a control scheme is proposed. According to the proposed control scheme, experimental system is constructed and experiments are performed. The experimental results show that the motor can operate steadily and the torque control can be decoupled from the suspending force control, which verifies the validity of the proposed structure and its control scheme.
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IAS - Comparative analysis of bearingless switched reluctance motors with decoupled suspending force control
2012 IEEE Industry Applications Society Annual Meeting, 2012Co-Authors: Donghee Lee, Jinwoo AhnAbstract:In this paper, two novel bearingless switched reluctance motors (BLSRMs), 12/14 hybrid Stator Pole BLSRM and 12/8 double Stator BLSRM, in which the torque control is naturally decoupled from the suspending force control are proposed. Both structures have two types of Stator Poles: torque and suspending force Poles. Due to the independent characteristics between the torque and suspending force Poles, the torque control can be decoupled from the suspending force control. The characteristics of the proposed structures, such as magnetic flux distribution, inductance, torque, suspending force, torque ripple and the number of switches used in the drive systems, are analyzed and compared. To verify the validity of the proposed structures, two prototypes of the proposed structures are compared and tested.
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hybrid Stator Pole switched reluctance motor to improve radial force for bearingless application
Energy Conversion and Management, 2011Co-Authors: Huijun Wang, Donghee Lee, Taehub Park, Jinwoo AhnAbstract:A novel hybrid Stator-Pole switched reluctance motor (HSPSRM) to improve radial force for bearingless application is presented in this paper. The proposed motor can generate a constant suspending force independent of rotor position only using small current excitation. And torque control can be naturally decoupled form suspending force control. Measured data and the results of numerical analysis are given to evaluate the motor structure. In the numerical analysis, the finite element method (FEM) is employed due to the highly nonlinear nature of the motor. A prototype hybrid Stator-Pole SRM is manufactured and tested in the experimental studies. The obtained test and simulation results show that the hybrid Stator-Pole SRM structure has a constant suspending force, which can be controlled independent from torque control.
Wei Hua - One of the best experts on this subject based on the ideXlab platform.
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Design and Analysis of a Hybridly Excited Asymmetric Stator Pole Doubly Salient Machine
IEEE Transactions on Industry Applications, 2020Co-Authors: Yishu Zhang, Lei Ning, Jianguo Zhu, Wei HuaAbstract:This article presents the design and analysis of a 12/7 (numbers of Stator/rotor Poles) hybridly excited asymmetric Stator Pole doubly salient machine (HEASPDSM) with a main focus on the special topology and operational principle by using the analytical and 2-D finite element analysis. A full comparison is conducted on the average torque, torque ripples, no-load back electromotive force and flux regulation capacity under the condition of different structural parameters, which can provide good references to the machine design. A 12/7 HEASPDSM is designed and the main performance indexes are analyzed in detail. Based on the parameters, the performance of 12/7 HEASPDSM is compared with traditional 6/7 doubly salient permanent magnet machine (DSPMM) with the same volume and thermal load. Finally, a prototype of the 12/7 HEASPDSM is manufactured and tested to validate the theoretical analysis. The results fully demonstrate that the HEASPDSM possesses the merits of strong flux regulation capability, higher torque density, and wider constant power speed range benefitted from the dc field winding than the traditional DSPMM.
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analysis and suppression of induced voltage pulsation in dc winding of five phase wound field switched flux machines
IEEE Transactions on Energy Conversion, 2019Co-Authors: Z Q Zhu, Wei Hua, Sam Akehurst, Xiaofeng Zhu, Wentao Zhang, Junming ZhuAbstract:In wound-field (WF) switched flux (SF) (WFSF) machines, the DC winding induced voltage pulsation causes current ripple in the DC winding and challenges the DC power source, and deteriorates the control performance. In this paper, the induced voltage pulsation in DC winding of five-phase WFSF machines is analyzed and its reduction methods are proposed. The cycles per electric period of the open-circuit and armature reaction induced voltage pulsation in DC winding are derived analytically. Modifying the airgap permeance by optimizing the rotor Pole arc or chamfering the rotor Pole surface, and axial pairing of rotor segments having rotor Pole with different arcs are used to suppress the induced voltage pulsation in DC winding, with >90% average torque maintained. Finite element results show that, by optimizing the rotor Pole arc, the peak-to-peak value of the induced voltage pulsation in DC winding can be effectively suppressed to 59.59%, 30.67%, 29.99% and 43.35% for the 10-Stator-Pole five-phase WFSF machines with 8-, 9-, 11- and 12-rotor-Pole rotors, respectively. By applying rotor Pole surface shaping, the induced voltage pulsation in DC winding peak-to-peak value can be effectively suppressed to 61.76%, 45.47% and 40.21% for the 8-, 9- and 12-rotor-Pole machines, respectively, while by applying axial pairing, it can be suppressed to 46.89%, 7.16%, 15.64% and 12.04%, respectively. The 10-Stator-Pole/12-rotor-Pole WFSF machines having the original rotor, optimized rotor, chamfered rotor and axial paired rotor are prototyped and the experiments validate the analytical and finite element results.
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Design of Hybrid Excited Asymmetric-Stator-Pole Doubly Salient Machine
2018 XIII International Conference on Electrical Machines (ICEM), 2018Co-Authors: Wei HuaAbstract:Doubly salient permanent magnet machine (DSPMM) enjoys the advantages of high torque density, simple rotor structure, high reliability, etc. However, the air-gap flux density is difficult to regulate due to that the air-gap magnetic field is produced only by permanent magnets (PMs). Thus, this paper proposes a hybrid excited asymmetric-Stator-Pole doubly salient machine (HE-ASPDSM) and its air-gap flux density can be regulated easily by controlling the excitation current of field winding. The topologies and operation principle of the HE-ASPDSM are studied firstly based on modern winding theory and two-dimension finite element analysis (2D FEA). Then, the comparison of no-load flux linkage, back electric magnetomotive force (EMF) and air-gap flux density of different topologies is made. Besides, the expression and harmonic components of airgap flux density are also derived based on mathematical analysis. And then, the influence of key design parameters on the cogging torque, flux regulation ability, electromagnetic torque, losses and efficiency is investigated in details. Finally, the analysis of main performance indexes is performed based on the proposed 12/7 (Stator/rotor Poles) HE-ASPDSM. It indicates that the proposed 12/7 HE-ASPDSM has strong air-gap flux regulation ability.
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influence of rotor Pole number on electromagnetic performance in 12 phase redundant switched flux permanent magnet machines for wind power generation
IEEE Transactions on Industry Applications, 2017Co-Authors: Lingyun Shao, Wei Hua, Z Q Zhu, Minghao Tong, Guishu Zhao, Fangbo Yin, Ming ChengAbstract:In this paper, electromagnetic performances of 12-phase 24-Stator-Pole redundant switched flux permanent magnet (SFPM) machines with 20-, 22-, 26-, and 28-rotor-Pole rotors designed for wind power generation are comparatively analyzed. The influence of key design parameters on the open-circuit phase electromotive force and cogging torque is comparatively evaluated by a 2-D finite-element analysis (FEA). FEA results show that the 24-/26-Pole SFPM machine exhibits the highest electromagnetic torque and efficiency than the other three, while the 24-/22-Pole one has the smallest cogging torque and torque ripple as well as relatively good voltage regulation and efficiency, which are essential for a wind generator. Furthermore, the investigation on redundancy performance shows that cross coupling among the four sets of three-phase balanced windings and the saturation effect can be neglected when the generator operates with relative light loads. Finally, the 12-phase 24-/22-Pole SFPM machine is built and tested to validate the simulations.
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Comparison of complementary and modular linear flux-switching motors with different mover and Stator Pole pitch
IEEE Transactions on Magnetics, 2013Co-Authors: Ruiwu Cao, Chris Mi, Ming Cheng, Wei Hua, Wenxiang ZhaoAbstract:Linear flux-switching permanent magnet (LFSPM) motors with both permanent magnets and armature windings on the short primary mover have attracted considerable attention due to their simple and cheap Stator which only consists of iron. Hence, this kind of liner motor is very suitable for long Stator applications such as in urban rail transportations. However, the conventional LFSPM motors directly split from rotary FSPM motor suffer from drawbacks such as unbalanced magnetic circuit of end coil, heavy mover, and bigger cogging force and force ripple. Modular LFSPM (MLFSPM) motors can mitigate the problem of unbalanced magnetic circuit of end coil. But some MLFSPM motors with different Stator/mover Pole pitch τs/τm=12/14, 12/10 don't have complementary phase armature windings, which will lead to asymmetrical and non-sinusoidal back-electromotive force, bigger cogging force and thrust force ripple. The key of this paper is to propose, investigate, and compare four complementary and modular structures for the LFSPM motors with different τs/τm . The electromagnetic performance and dimensions of the proposed complementary MLFSPM motors with different τs/τm are investigated, compared and confirmed by the means of finite element analysis and experimental results. Based on the analysis results, two complementary MLFSPM motors with τs/τm=12/13 are chosen to be the two best motors, which can offer the biggest thrust force, relatively smaller cogging force and thrust force ripple, and shorter mover length.
Iqbal Husain - One of the best experts on this subject based on the ideXlab platform.
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Permanent magnet transverse flux machine with overlapping Stator Poles
2015 IEEE Energy Conversion Congress and Exposition (ECCE), 2015Co-Authors: Adeeb Ahmed, Zhao Wan, Iqbal HusainAbstract:A Transverse Flux Machine (TFM) topology with ring winding configuration is proposed. A novel approach for Stator Pole configuration is presented that ensures lower leakage between adjacent Poles. The unique Stator Pole configuration permits an overlapping region between adjacent Stator Poles resulting in a significant improvement in space utilization that helps attain higher torque-to-volume ratio. In addition, the innovative Pole design reduces the end winding length which helps reduce the copper mass. Simulation results are presented based on 3D Finite Element Analysis (FEA). Significant performance improvement was achieved compared to similar transverse flux machines.