The Experts below are selected from a list of 4110 Experts worldwide ranked by ideXlab platform
Baowei Song - One of the best experts on this subject based on the ideXlab platform.
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Eddy Current Loss and detuning effect of seawater on wireless power transfer
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020Co-Authors: Kehan Zhang, Zhengchao Yan, Baowei SongAbstract:Due to the conductivity of the seawater, the traditional mutual inductance circuit model in the air cannot be used directly to describe wireless power transfer (WPT) systems in seawater applications. This paper proposes a modified mutual inductance circuit model of an underwater WPT system to analyze the Eddy Current Loss (ECL) and the detuning effect caused by the seawater. The time-harmonic electromagnetic field in the seawater and the air near the coil that carries a sinusoidal alternating Current is analyzed. The root-mean-square (rms) value and phase angle of the induced voltage on the secondary coil can be obtained by the integral of the electric field intensity along the coil path. By introducing the equivalent ECL impedance at both the primary and secondary sides, a modified mutual inductance circuit model of an underwater WPT system was obtained. Through adding a compensation inductance to the primary circuit, the detuned system in the seawater is turned back to be resonant at the same frequency as in the air. A seawater WPT prototype was built and the experimental results verified the theoretical analysis.
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frequency optimization of a loosely coupled underwater wireless power transfer system considering Eddy Current Loss
IEEE Transactions on Industrial Electronics, 2019Co-Authors: Zhengchao Yan, Yiming Zhang, Tianze Kan, Kehan Zhang, Baowei SongAbstract:Wireless power transfer (WPT) has attracted much attention in recent years. In an underwater WPT system, the Eddy Current Loss tends to be non-negligible as the frequency or the coil Current increases. Thus, it is crucial to analyze the Eddy Current Loss in an underwater WPT system. The analytical model of the Eddy Current Loss of a coreless WPT system in the seawater is established with Maxwell's equations. The expressions of the electric field intensity and the Eddy Current Loss are derived. The Eddy Current Loss is analyzed in different circumstances to illustrate the impacts of related factors. For a WPT system in the air, there is an optimum resonant frequency, for a higher frequency leads to a larger induced voltage, but will result in larger coil Losses simultaneously. However, the optimum resonant frequency will be shifted because of the Eddy Current Loss in the seawater. Then, the optimum operating frequency is obtained based on the analytical model. It is found that the optimum operating frequency is supposed to be larger than the resonant frequency to achieve the maximum dc–dc efficiency in the seawater. An underwater WPT prototype was built and the experimental results verified the theoretical analysis.
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a new coil structure to reduce Eddy Current Loss of wpt systems for underwater vehicles
IEEE Transactions on Vehicular Technology, 2019Co-Authors: Kehan Zhang, Zhengchao Yan, Xinyi Zhang, Zhengbiao Zhu, Baowei SongAbstract:Wireless power transfer systems in seawater inevitably suffer some energy Loss as a consequence of Eddy Current Loss. Here, we present a coil structure utilizing two transmitter coils placed symmetrically adjacent to each side of the receiver coil. This coil arrangement, termed a 1 × 1 × 1 structure, yields improved power transfer efficiency. The Eddy Current Loss caused by the transmitter coils in a 1 × 1 × 1 system can be reduced to roughly half of that in a 1 × 1 system, with one transmitter coil and one receiver coil. The experimental results show that the power transfer efficiency from the transmitter to the receiver is improved by nearly 10%. After the introduction of equivalent Eddy Current Loss impedance into the circuit, two arrangements of the 1 × 1 × 1 circuit topology are investigated. They consist of a shared or separately compensated capacitance topology. It is found that the shared-compensated capacitance topology is more robust to the change of mutual inductance than the separately compensated capacitance topology. This kind of structure is very useful in underwater vehicle applications.
Kehan Zhang - One of the best experts on this subject based on the ideXlab platform.
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Eddy Current Loss and detuning effect of seawater on wireless power transfer
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020Co-Authors: Kehan Zhang, Zhengchao Yan, Baowei SongAbstract:Due to the conductivity of the seawater, the traditional mutual inductance circuit model in the air cannot be used directly to describe wireless power transfer (WPT) systems in seawater applications. This paper proposes a modified mutual inductance circuit model of an underwater WPT system to analyze the Eddy Current Loss (ECL) and the detuning effect caused by the seawater. The time-harmonic electromagnetic field in the seawater and the air near the coil that carries a sinusoidal alternating Current is analyzed. The root-mean-square (rms) value and phase angle of the induced voltage on the secondary coil can be obtained by the integral of the electric field intensity along the coil path. By introducing the equivalent ECL impedance at both the primary and secondary sides, a modified mutual inductance circuit model of an underwater WPT system was obtained. Through adding a compensation inductance to the primary circuit, the detuned system in the seawater is turned back to be resonant at the same frequency as in the air. A seawater WPT prototype was built and the experimental results verified the theoretical analysis.
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frequency optimization of a loosely coupled underwater wireless power transfer system considering Eddy Current Loss
IEEE Transactions on Industrial Electronics, 2019Co-Authors: Zhengchao Yan, Yiming Zhang, Tianze Kan, Kehan Zhang, Baowei SongAbstract:Wireless power transfer (WPT) has attracted much attention in recent years. In an underwater WPT system, the Eddy Current Loss tends to be non-negligible as the frequency or the coil Current increases. Thus, it is crucial to analyze the Eddy Current Loss in an underwater WPT system. The analytical model of the Eddy Current Loss of a coreless WPT system in the seawater is established with Maxwell's equations. The expressions of the electric field intensity and the Eddy Current Loss are derived. The Eddy Current Loss is analyzed in different circumstances to illustrate the impacts of related factors. For a WPT system in the air, there is an optimum resonant frequency, for a higher frequency leads to a larger induced voltage, but will result in larger coil Losses simultaneously. However, the optimum resonant frequency will be shifted because of the Eddy Current Loss in the seawater. Then, the optimum operating frequency is obtained based on the analytical model. It is found that the optimum operating frequency is supposed to be larger than the resonant frequency to achieve the maximum dc–dc efficiency in the seawater. An underwater WPT prototype was built and the experimental results verified the theoretical analysis.
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a new coil structure to reduce Eddy Current Loss of wpt systems for underwater vehicles
IEEE Transactions on Vehicular Technology, 2019Co-Authors: Kehan Zhang, Zhengchao Yan, Xinyi Zhang, Zhengbiao Zhu, Baowei SongAbstract:Wireless power transfer systems in seawater inevitably suffer some energy Loss as a consequence of Eddy Current Loss. Here, we present a coil structure utilizing two transmitter coils placed symmetrically adjacent to each side of the receiver coil. This coil arrangement, termed a 1 × 1 × 1 structure, yields improved power transfer efficiency. The Eddy Current Loss caused by the transmitter coils in a 1 × 1 × 1 system can be reduced to roughly half of that in a 1 × 1 system, with one transmitter coil and one receiver coil. The experimental results show that the power transfer efficiency from the transmitter to the receiver is improved by nearly 10%. After the introduction of equivalent Eddy Current Loss impedance into the circuit, two arrangements of the 1 × 1 × 1 circuit topology are investigated. They consist of a shared or separately compensated capacitance topology. It is found that the shared-compensated capacitance topology is more robust to the change of mutual inductance than the separately compensated capacitance topology. This kind of structure is very useful in underwater vehicle applications.
Katsumi Yamazaki - One of the best experts on this subject based on the ideXlab platform.
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investigation of locked rotor test for estimation of magnet pwm carrier Eddy Current Loss in synchronous machines
IEEE Transactions on Magnetics, 2012Co-Authors: Katsumi Yamazaki, T Fukuoka, Kan Akatsu, Noriya Nakao, Alex RudermanAbstract:The measurement method on the basis of locked rotor tests has been developed for the estimation of magnet PWM carrier Eddy Current Loss in synchronous machines. In the measurement, the magnet Eddy Current Loss is separated from the other Losses by subtracting the Loss of the machine without the magnets from that with the magnets under the appropriate control of armature Currents and voltages. The 3-D finite element analysis is also carried out in order to confirm the validity of the proposed measurement method. The measured and calculated results are found to be in good agreement. It is clarified that the magnet Eddy Current Loss of the machine can be predicted from the results of the proposed measurement method.
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effect of Eddy Current Loss reduction by magnet segmentation in synchronous motors with concentrated windings
IEEE Transactions on Industry Applications, 2011Co-Authors: Katsumi Yamazaki, Yu FukushimaAbstract:In this paper, we investigate the effect of Eddy-Current Loss reduction by the magnet segmentation in synchronous motors with concentrated windings in order to understand appropriate segmentation methods. The Loss-reduction effects in each harmonic Eddy Current in the magnets are analyzed by both the theoretical solution and the three-dimensional finite-element analysis with Fourier transformation. The basic experiments using magnet specimens are carried out in order to support the calculated results. It is clarified that the Loss-reduction effect varies with the harmonic orders and that the effect depends on the types of the rotors, for instance, interior and surface permanent-magnet rotors.
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effect of Eddy Current Loss reduction by magnet segmentation in synchronous motors with concentrated windings
International Conference on Electrical Machines and Systems, 2009Co-Authors: Katsumi Yamazaki, Yu FukushimaAbstract:In this study, we investigate the effect of Eddy-Current Loss reduction by magnet segmentation in synchronous motors with concentrated windings. The Loss-reduction effects in each harmonic Eddy Currents in the magnets are analyzed by both the theoretical solution and the 3-D finite element analysis with Fourier transformation. Basic experiments using magnet specimens are carried out in order to support the calculated results. It is clarified that the Loss reduction effect varies with the harmonic orders and that the effect depends on the types of the rotors, for example, interior and surface magnet types.
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effect of Eddy Current Loss reduction by segmentation of magnets in synchronous motors difference between interior and surface types
IEEE Transactions on Magnetics, 2009Co-Authors: Katsumi Yamazaki, Yuji Kanou, Masayuki Shina, Masashi Miwa, Jun HagiwaraAbstract:In this study, we investigate the effect of Eddy Current Loss reduction by segmented rare-earth magnets that are used in synchronous motors driven by inverters. First, the difference in the Loss-reduction effect due to the rotor shape is estimated by the 3-D finite-element analysis that considers the carrier harmonics of the inverter. The results are compared to the theoretical solution. Next, a basic experiment using magnet specimens is carried out in order to confirm the calculated results. It is clarified that most of the magnet Eddy Current Losses in the analyzed motors are caused by the carrier harmonics of the inverter and that the Loss-reduction effect of the segmented magnet in the case of the interior permanent magnet motor decreases when it is compared to that of the surface permanent magnet motor. This phenomenon is mainly caused by the increase in the reaction field by the high-frequency harmonic Eddy Currents.
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reduction of magnet Eddy Current Loss in interior permanent magnet motors with concentrated windings
Energy Conversion Congress and Exposition, 2009Co-Authors: Katsumi Yamazaki, Yu Fukushima, Yuji Kanou, Shunji Ohki, Akira Nezu, Takeshi Ikemi, Ryoichi MizokamiAbstract:In this paper, we develop stator and rotor shapes of interior permanent magnet motors with concentrated windings in order to reduce Eddy Current Loss of the magnets at high rotational speeds under field weakening control. First, main factors that cause the magnet Eddy Current Loss in the motor are investigated from results of the three-dimensional finite-element method. The magnet Eddy Current Loss is separated into three components due to their origins and the largest component is specified. With this result, an automatic shape optimization is carried out to determine the stator and rotor shapes, which reduce the magnet Eddy Current Loss without significant decreases in the torque. Finally, the proposed stator and rotor are manufactured in order to confirm the characteristics. The advantages over the conventional motor are clarified.
D Howe - One of the best experts on this subject based on the ideXlab platform.
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analysis and reduction of magnet Eddy Current Loss in flux switching permanent magnet machines
4th IET International Conference on Power Electronics Machines and Drives (PEMD 2008), 2008Co-Authors: Z Q Zhu, D Howe, Y Pang, S Iwasaki, R Deodhar, J T Chen, R L Owen, Adam PrideAbstract:The flux-switching permanent magnet machine has permanent magnets on the stator. The magnet Eddy Current Loss has never been addressed in literature and is investigated in this paper by the finite element method. The influence of operation modes, i.e. constant torque and flux weakening control, is considered, and the methods of reducing the magnet Eddy Current Loss are also discussed.
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rotor Eddy Current Loss in single phase permanent magnet brushless dc motor
IEEE Industry Applications Society Annual Meeting, 2007Co-Authors: Yiguang Chen, D Howe, Z Q Zhu, J H GliemannAbstract:Due to spatial harmonics in the pulsating stator mmf and temporal harmonics in the excitation Current, a significant Eddy Current Loss may be induced in the rotor of a single-phase permanent magnet brushless dc (BLDC) motor. The Eddy Current Loss is also dependent on the level of airgap asymmetry which is employed to facilitate unidirectional rotation. The paper investigates the Eddy Current Loss which results in the permanent magnets and retaining sleeve of a 1.1 kW, 45 krpm, single-phase BLDC motor, and considers the influence of the phase Current waveform and the level of airgap asymmetry, as well as the effectiveness of segmenting the magnets in reducing the Loss.
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Eddy Current Loss in the frame of a flux switching permanent magnet machine
IEEE International Magnetics Conference, 2006Co-Authors: Y Pang, D Howe, Z Q Zhu, S Iwasaki, R Deodhar, Adam PrideAbstract:In flux-switching permanent magnet machines, a significant leakage flux exists at the outer surface of the stator core. Since the leakage flux varies as the rotor rotates, a significant Eddy Current Loss may be induced in the nonmagnetic frame. The leakage flux and the associated Eddy Current Loss in a representative flux-switching machine are investigated by finite element analysis, on both open-circuit and at rated load, predicted results being validated experimentally. In addition, the effectiveness of introducing slots in the frame to reduce the Eddy Current Loss is investigated
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Eddy Current Loss in the rotor magnets of permanent magnet brushless machines having a fractional number of slots per pole
IEEE Transactions on Magnetics, 2005Co-Authors: Dahaman Ishak, D HoweAbstract:We develop an analytical model for predicting the Eddy-Current Loss in the rotor magnets of permanent-magnet brushless machines that have a fractional number of slots per pole, when either all the teeth or only alternate teeth are wound, and in which the unwound teeth may be narrower than the wound teeth. The model enables the magnetic field distribution in the air gap and magnet regions to be determined, by neglecting the Eddy-Current redistribution effect and assuming that the Eddy Currents are resistance limited. It can account for space-harmonic magnetomotive forces (MMFs) resulting from the winding distribution and time-harmonic MMFs due to nonsinusoidal phase Currents, as well as for the effect of curvature and circumferential segmentation of the magnets. We have validated the model by finite-element analysis, and used it to investigate the Eddy-Current Loss in the magnets of three surface-mounted magnet brushless motors that have similar slot and pole numbers, and employ identical rotors but different stators, when they are operated in brushless ac (BLAC) and dc (BLDC) modes. We show that the stator winding configuration, as well as the operational mode, significantly influence the resultant Eddy-Current Loss.
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improved analytical modelling of rotor Eddy Current Loss in brushless machines equipped with surface mounted permanent magnets
IEE Proceedings - Electric Power Applications, 2004Co-Authors: K Ng, N Schofield, D HoweAbstract:An improved analytical model for predicting the rotor Eddy Current Loss in brushless machines equipped with surface-mounted permanent magnets is presented. It is formulated in polar co-ordinates and based on the calculation of the two-dimensional electromagnetic field in the airgap/magnet regions, with due account of the Eddy Current reaction field. It enables the Eddy Current Loss in the permanent magnets and the retaining sleeve, if fitted, to be calculated, and caters for motors having either overlapping or non-overlapping stator windings, as well as any specified load condition. The analysis accounts for both time and space mmf harmonics, but neglects the influence of stator slotting. The model is applied to a brushless DC traction machine in which the rotor Loss is due predominantly to time harmonics in the armature reaction field which result from commutation events. The predicted rotor Loss is compared with the Loss deduced from thermometric measurements and from an analytical magnetostatic model which neglects the Eddy Current reaction field. Good agreement between predictions and measurements is achieved over the complete operating speed range.
Zhengchao Yan - One of the best experts on this subject based on the ideXlab platform.
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Eddy Current Loss and detuning effect of seawater on wireless power transfer
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020Co-Authors: Kehan Zhang, Zhengchao Yan, Baowei SongAbstract:Due to the conductivity of the seawater, the traditional mutual inductance circuit model in the air cannot be used directly to describe wireless power transfer (WPT) systems in seawater applications. This paper proposes a modified mutual inductance circuit model of an underwater WPT system to analyze the Eddy Current Loss (ECL) and the detuning effect caused by the seawater. The time-harmonic electromagnetic field in the seawater and the air near the coil that carries a sinusoidal alternating Current is analyzed. The root-mean-square (rms) value and phase angle of the induced voltage on the secondary coil can be obtained by the integral of the electric field intensity along the coil path. By introducing the equivalent ECL impedance at both the primary and secondary sides, a modified mutual inductance circuit model of an underwater WPT system was obtained. Through adding a compensation inductance to the primary circuit, the detuned system in the seawater is turned back to be resonant at the same frequency as in the air. A seawater WPT prototype was built and the experimental results verified the theoretical analysis.
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frequency optimization of a loosely coupled underwater wireless power transfer system considering Eddy Current Loss
IEEE Transactions on Industrial Electronics, 2019Co-Authors: Zhengchao Yan, Yiming Zhang, Tianze Kan, Kehan Zhang, Baowei SongAbstract:Wireless power transfer (WPT) has attracted much attention in recent years. In an underwater WPT system, the Eddy Current Loss tends to be non-negligible as the frequency or the coil Current increases. Thus, it is crucial to analyze the Eddy Current Loss in an underwater WPT system. The analytical model of the Eddy Current Loss of a coreless WPT system in the seawater is established with Maxwell's equations. The expressions of the electric field intensity and the Eddy Current Loss are derived. The Eddy Current Loss is analyzed in different circumstances to illustrate the impacts of related factors. For a WPT system in the air, there is an optimum resonant frequency, for a higher frequency leads to a larger induced voltage, but will result in larger coil Losses simultaneously. However, the optimum resonant frequency will be shifted because of the Eddy Current Loss in the seawater. Then, the optimum operating frequency is obtained based on the analytical model. It is found that the optimum operating frequency is supposed to be larger than the resonant frequency to achieve the maximum dc–dc efficiency in the seawater. An underwater WPT prototype was built and the experimental results verified the theoretical analysis.
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a new coil structure to reduce Eddy Current Loss of wpt systems for underwater vehicles
IEEE Transactions on Vehicular Technology, 2019Co-Authors: Kehan Zhang, Zhengchao Yan, Xinyi Zhang, Zhengbiao Zhu, Baowei SongAbstract:Wireless power transfer systems in seawater inevitably suffer some energy Loss as a consequence of Eddy Current Loss. Here, we present a coil structure utilizing two transmitter coils placed symmetrically adjacent to each side of the receiver coil. This coil arrangement, termed a 1 × 1 × 1 structure, yields improved power transfer efficiency. The Eddy Current Loss caused by the transmitter coils in a 1 × 1 × 1 system can be reduced to roughly half of that in a 1 × 1 system, with one transmitter coil and one receiver coil. The experimental results show that the power transfer efficiency from the transmitter to the receiver is improved by nearly 10%. After the introduction of equivalent Eddy Current Loss impedance into the circuit, two arrangements of the 1 × 1 × 1 circuit topology are investigated. They consist of a shared or separately compensated capacitance topology. It is found that the shared-compensated capacitance topology is more robust to the change of mutual inductance than the separately compensated capacitance topology. This kind of structure is very useful in underwater vehicle applications.
