The Experts below are selected from a list of 1398 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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investigation of dc winding induced voltage in hybrid excited switched flux permanent magnet machine
IEEE Transactions on Industry Applications, 2020Co-Authors: Xiaoyong Sun, Z. Q. ZhuAbstract:The dc winding induced voltage in hybrid-excited machines can lead to dc winding current ripple and hence, fluctuating field excitation. It may also challenge the dc power source and increase the difficulty of machine control, especially at high speed. The dc winding induced voltage in a hybrid-excited switched-flux permanent magnet (HESFPM) machine is investigated in this article. The phenomenon and mechanism of the dc winding induced voltages under both open-circuit and on-load conditions are analyzed, with particular emphasis on on-load operation which consists of open-circuit induced voltage and armature current induced voltage, respectively. Two techniques, i.e., Rotor step skewing and unequal Rotor Teeth, are proposed and comparatively investigated by the finite-element (FE) method to suppress the dc winding induced voltage under on-load condition. FE results show that the peak-to-peak value of on-load dc winding induced voltage can be effectively suppressed by 96.15% or 89.05% by Rotor step skewing or unequal Rotor Teeth, respectively, while the average on-load electromagnetic torque can be maintained at 89.4% or 87.8%. A prototype HESFPM machine is built and tested to verify the FE results.
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reduction of open circuit dc winding induced voltage in hybrid excited switched flux permanent magnet machine
International Conference on Ecological Vehicles and Renewable Energies, 2019Co-Authors: X Y Sun, Z. Q. ZhuAbstract:The open-circuit DC winding induced voltage in a hybrid-excited switched-flux permanent magnet (HESFPM) machine is investigated in this paper. The phenomenon of the DC winding induced voltage under open-circuit condition is presented and the mechanism of this phenomenon is explained. Rotor step skewing and unequal Rotor Teeth are comparatively investigated by the finite element (FE) method to reduce the open-circuit DC winding induced voltage. FE results show that the peak to peak value of the open-circuit DC winding induced voltage can be effectively reduced by 78.87% with 5-step Rotor skewing, whilst the average electromagnetic torque can be maintained at 96.74%. By using unequal Rotor Teeth, the peak to peak value of the open-circuit DC winding induced voltage can be reduced by 95.43% and 86.54% for the optimal machines 2 and 3, respectively, whilst the average electromagnetic torque can be maintained at 89.93% and 94.62%, respectively.
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analysis of open circuit dc winding induced voltage in partitioned stator hybrid excited switched flux machine
International Conference on Ecological Vehicles and Renewable Energies, 2019Co-Authors: X Y Sun, Z. Q. ZhuAbstract:This paper analyses the DC winding induced voltage in a partitioned-stator hybrid-excited switched-flux permanent magnet (PS-HESFPM) machine under open-circuit operation. The phenomenon and mechanism of the open-circuit DC winding induced voltage are described. Two techniques are proposed and comparatively analyzed by the finite element (FE) method to reduce the open-circuit DC winding induced voltage, i.e., Rotor pole arc pairing and unevenly distributed Rotor Teeth, respectively. FE results show that the peak to peak value of the open-circuit DC winding induced voltage can be reduced by 89.89% and 88.73%, whilst the average on-load electromagnetic torque can be maintained at 97.64% and 97.02%, by using Rotor pole arc paring and unevenly distributed Rotor Teeth, respectively.
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influence of design parameters on output torque of flux switching permanent magnet machines
Vehicle Power and Propulsion Conference, 2008Co-Authors: Z. Q. Zhu, Y Pang, J T Chen, Z P Xia, David HoweAbstract:The influence of design parameters of a flux-switching PM (FSPM) machine for maximum output torque has been investigated by finite element analyses and validated by measurements made on a prototype FSPM motor. These parameters include the split ratio of the inner diameter to outer diameter of the stator, the stator tooth width, the stator magnet thickness, the stator back-iron thickness, the stator lamination bridge, the Rotor tooth width and height, and the Rotor back-iron thickness. In addition, the influence of the shape of the magnets and the Rotor Teeth has been investigated. It shows that the FSPM machine having equal stator tooth width, stator magnet thickness and slot opening produces the maximum output torque. The torque can be increased if the stator back-iron thickness is reduced to ~70% of the stator tooth width to increase the slot area. The output torque can be increased by ~8% if the Rotor tooth width is increased by 40%~60%. The optimal split ratio for maximum output torque is ~0.55-0.6 when the copper loss is fixed to 50 W and increases with an increase in the copper loss. The influence of other design parameters is found to be less significant for an appropriately designed motor.
Ming Cheng - One of the best experts on this subject based on the ideXlab platform.
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comparative study of five phase hefs machines with different stator poles Rotor Teeth combinations and armature winding connections
International Conference on Electrical Machines and Systems, 2020Co-Authors: Minghao Tong, Ming Cheng, Guishu ZhaoAbstract:In this paper, five-phase E-core hybrid-excitation flux-switching (HEFS) machines with three different stator poles/Rotor Teeth (P/T) combinations (namely 10/18, 10/19, 10/21) are compared, and two armature winding connection methods for each combination are investigated respectively. Firstly, the topologies of the machines are analyzed theoretically and the consistency and complementarity of one phase armature winding are explained. Then, the electromagnetic performances, including phase flux-linkage and back electro-motive-force (EMF), flux-regulation ratio, electromagnetic torque and cogging torque of the proposed machines, are predicted by means of the two-dimensional (2-D) finite-element analysis (FEA). Moreover, the discussions about the predicted results of three HEFS machines are given, which indicates the optimal choice on P/T combinations and armature winding connection methods of E-core HEFS machines.
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cogging torque minimization in flux switching permanent magnet machines by tooth chamfering
European Conference on Cognitive Ergonomics, 2016Co-Authors: Ming ChengAbstract:Due to the nature of doubly salient structure and high air-gap flux density, flux-switching permanent magnet (FSPM) machines typically suffer from large cogging torque, causing undesired acoustic noise and vibration, especially at low speeds. In this paper, various tooth chamfering methods for a 12/10 FSPM machine are proposed to reduce cogging torque. The influences of both circular bead and right angle as well as their possible combinations on cogging torque are investigated by 2D finite element analysis (FEA), and it turns out that employing right angles in both stator and Rotor Teeth is the most effective solution. Further, in order to explain this phenomena, the air-gap flux density is analyzed. Besides, the impacts on phase back electro-motive-force and electromagnetic torque are also evaluated. The predicted results indicate that the proposed technique can significantly reduce the peak value of cogging torque from 2.6Nm to 0.4Nm, while the reduction of average torque is only about 1.6%, which turns out to be an improvement when compared with the approach employed in previous literatures.
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thermal analysis and cooling system design of dual mechanical port machine for wind power application
IEEE Transactions on Industrial Electronics, 2013Co-Authors: Xikai Sun, Ming ChengAbstract:Dual mechanical port (DMP) machine, a kind of electrical continuous variable transmission, is a very competitive alternative for vulnerable constant speed-ratio mechanical gearbox in wind power application and hybrid electrical vehicles. As the inner wound Rotor is surrounded by the stator and the permanent magnet (PM) outer Rotor, the DMP machine suffers from possible PM demagnetization and insulation failure under severe thermal condition. In this paper, thermal analysis and cooling system design of a DMP prototype machine are investigated. To predict the heat sources in actual operation, a transient cosimulation method is presented. Thermal parameters and the flow distribution in the cooling ducts are calculated in detail. Finite-element analysis of the thermal field is carried out to obtain the temperature distribution and two typical thermal contacts are considered. A robust fully forced-air cooling system with inner Rotor Teeth ducts is proposed for the DMP machine and a 10-kW DMP machine is prototyped. Experimental results at different working conditions are given to verify the theoretical analysis. Both simulation and experimental results reveal that the numerical approach and the proposed cooling system are not only more accurate and reliable, but can be referred to other electrical machine cooling system design.
Karthikeyan Rajagopal - One of the best experts on this subject based on the ideXlab platform.
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effect of skewing the Rotor Teeth on the performance of doubly salient permanent magnet motors
Journal of Applied Physics, 2006Co-Authors: N.k. Sheth, A R C Sekharbabu, Karthikeyan RajagopalAbstract:This paper presents the effects of skewing the Rotor Teeth on the performance characteristics such as flux linkage, back emf, phase inductance, and reluctance torque of an 8∕6 doubly salient permanent magnet motor using a simple method, which utilizes the results obtained from the two-dimensional finite element analysis. The optimum skewing angle is obtained as 12°–15° for the least ripple torque without much reduction in the back emf. Skewing the Rotor Teeth of an 8∕6 doubly salient permanent magnet motor by 12°–15° will reduce the total harmonic distortion of the back emf profile to 29.69% from the original value of 44.69%. The reduction in the amplitude of the back emf in this case will be 18.79% only.
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Optimum pole arcs for a switched reluctance motor for higher torque with reduced ripple
IEEE Transactions on Magnetics, 2003Co-Authors: N.k. Sheth, Karthikeyan RajagopalAbstract:In this paper, the results of a two-dimensional (2-D) finite element (FE) analysis carried out on a 8/6 switched reluctance motor with a view to arrive at the optimum pole arcs for the stator and Rotor Teeth are presented. The authors have put forward a new method for calculating the average torque for comparison of static torque profiles to identify the optimum one. In this new method, 15/spl deg/ of the static torque profile, where the developed torque is nearly constant is considered for calculating the average torque. Operating the motor in this range instead of the first quarter cycle of the static torque profile will ensure higher average torque with minimum ripple. This average torque is considered as the parameter for comparison of different torque profiles of various pole arcs for the stator and Rotor. It is observed that the geometry with the existing stator pole arc of 20.2/spl deg/ and a changed Rotor pole arc of 30/spl deg/, instead of the existing 23.5/spl deg/ will be the optimum for this motor, as it gives the highest average torque with the minimum ripple.
Youtong Fang - One of the best experts on this subject based on the ideXlab platform.
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a novel doubly fed flux switching permanent magnet machine with armature windings wound on both stator poles and Rotor Teeth
IEEE Transactions on Industrial Electronics, 2020Co-Authors: Jiabei Zhu, Youtong FangAbstract:In this article, a novel doubly-fed flux-switching permanent magnet (DF-FSPM) machine is proposed, whose armature windings are wound on both stator poles and Rotor Teeth. Different from the conventional FSPM machine in which the armature windings are only located in the stator, the Rotor slot area is fully utilized in the DF-FSPM machine to improve the electrical loadings and, thus, the torque density. Moreover, it has the potential of fault-tolerant operation, since it comprises two sets of armature windings, which can work individually. The topology and the operating principle of the machine are introduced with reference to a 12-stator-pole/10-Rotor-tooth DF-FSPM machine. The electromagnetic performances of the optimized DF-FSPM machine and its FSPM counterpart machine are compared, including the induced voltage, inductances, torque capability, flux weakening capability, efficiency, and power factor. It shows that the DF-FSPM machine can exhibit about 46.5% higher torque density than the FSPM machine, while its torque production per magnet volume is also improved by about 39.6%. In addition, the efficiency and power factor of the DF-FSPM machine are higher than those of the FSPM machine. Finally, experimental validation is conducted on a prototype machine.
Rachid Ibtiouen - One of the best experts on this subject based on the ideXlab platform.
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nonlinear analytical prediction of magnetic field and electromagnetic performances in switched reluctance machines
IEEE Transactions on Magnetics, 2017Co-Authors: Zakarya Djelloulkhedda, Kamel Boughrara, Frédéric Dubas, Rachid IbtiouenAbstract:This paper deals with the nonlinear analytical harmonic modeling (HM) of three phases, and 6/4 conventional switched reluctance machine (SRM). The proposed model consists in computing magnetic field distribution and electromagnetic performances of an SRM with conventional winding. Because an SRM has inherently nonlinear characteristics, the analytical subdomain model that does not take into account the saturation has a limited accuracy. This is due to the assumption of infinite tooth permeability. The new analytical model (AM) based on the HM technique, which overcomes this limitation, is presented with the consideration of the local magnetic saturation on the stator and Rotor Teeth. The results obtained with the nonlinear AM have been compared with the linear AM based on the subdomain method (i.e., without the saturation effect) and nonlinear finite-element method solutions.
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Semi-Analytical Modeling of Spoke-Type Permanent-Magnet Machines Considering the Iron Core Relative Permeability: Subdomain Technique and Taylor Polynomial
Progress In Electromagnetics Research (PIER) B, 2017Co-Authors: Lazhar Roubache, Kamel Boughrara, Frédéric Dubas, Rachid IbtiouenAbstract:This article presents a novel contribution to the improvement of the analytic modeling of electrical machines using two-dimensional (2-D) subdomain technique with Taylor polynomial. To validate this novel method, the semi-analytical model has been implemented for spoke-type permanentmagnet (PM) machines (STPMM). Magnetostatic Maxwell’s equations are solved in polar coordinates and in all parts of the machine. The global solution is obtained by using the traditional boundary conditions (BCs), in addition to new radial BCs (e.g., between the PMs and the Rotor Teeth) which are traduced into a system of linear equations according to Taylor series expansion. The magnetic field calculations are performed for two different values of iron core relative permeability (viz., 10 and 1,000) and compared to finite-element method (FEM) predictions. The results show that a very good agreement is obtained.
