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P Farah - One of the best experts on this subject based on the ideXlab platform.
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analysis and reduction of on load dc winding Induced Voltage in wound field switched flux machines
IEEE Transactions on Industrial Electronics, 2020Co-Authors: C Wang, J C Mipo, Sophie Personnaz, P FarahAbstract:DC winding Induced Voltage pulsation in wound field switched flux (WFSF) machines causes dc winding current ripple and field excitation fluctuation, challenges the dc power source, and deteriorates the control performance. Hence, reducing this pulsation is important in the design of a WFSF machine. In this paper, based on the analytical models, rotor skewing and rotor iron piece pairing are proposed and comparatively investigated by the finite-element (FE) method to reduce the on-load dc winding Induced Voltage in WFSF machines having partitioned stators and concentrated ac windings. FE results show that peak-to-peak value of the on-load dc winding Induced Voltage in the analyzed 12/10-pole partitioned stator WFSF (PS-WFSF) machines can be reduced by 78.42% or 77.16% by using rotor skewing or rotor pairing, respectively, while the torque density can be maintained by >90%. As for the 12/11-, 12/13-, and 12/14-pole PS-WFSF machines, by using rotor iron piece inner arc pairing, the on-load dc winding Induced Voltage can be reduced by 64.11%, 52.12%, and 76.49%, respectively, while the torque density can be maintained by more than 90%. Prototypes are built and tested to verify the analytical and FE results.
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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: 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.
Chun T Rim - One of the best experts on this subject based on the ideXlab platform.
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Self-Inductance-Based Metal Object Detection With Mistuned Resonant Circuits and Nullifying Induced Voltage for Wireless EV Chargers
IEEE Transactions on Power Electronics, 2019Co-Authors: Seog Y Jeong, Van X. Thai, Jun H. Park, Chun T RimAbstract:In this paper, a metal object detection (MOD) system, a kind of foreign object detection (FOD), which is based on mistuned resonant circuits and utilizes the variation of self-inductance of a sensing pattern, is newly proposed for wireless electric vehicle (EV) chargers. The sensing pattern that consists of multiple loop coil sets is mounted on the transmitting (Tx) pad of an EV charger, where a loop coil set has two coils connected in series with the opposite polarity to cancel out the Induced Voltage generated by the Tx coil. Variation of self-inductance of the loop coil set is detected by a parallel-resonant circuit, driven by a current source and operating at near 1 MHz, in order to enhance the resolution of the proposed MOD system. To increase the detection sensitivity of the proposed MOD system, instead of an exact resonant frequency, a mistuned operating frequency near the –3 dB point is utilized for the parallel-resonant circuit. In this way, the proposed MOD system can detect very small metal objects regardless of their position and orientation on the Tx coil without any blind zone. Through simulations and experiments, it is found that the proposed MOD system detects not only horizontal but also standing upright metal objects. A prototype MOD system, operating at 85 kHz to satisfy the standard J2954, was fabricated to verify its feasibility. The results showed that output Voltage change of the proposed MOD system becomes 22.7% for a piece of the aluminum foil of 3 × 3 cm2 and 40.9% for 100 Korean Won coin.
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dual purpose nonoverlapping coil sets as metal object and vehicle position detections for wireless stationary ev chargers
IEEE Transactions on Power Electronics, 2018Co-Authors: Seog Y Jeong, Hyung G Kwak, Gi C Jang, Su Y Choi, Chun T RimAbstract:For commercialization of wireless stationary electric vehicles (EV) chargers, metal object detection (MOD) on a power supply coil and detection of position (DoP) of EVs are needed. In this paper, dual-purpose nonoverlapping coil sets for both MOD and DoP, which detect a variation of magnetic flux on the power supply coil, are newly proposed, where the proposed MOD and DoP methods make no contribution to any power losses. The existence of metal objects on the power supply coil is determined by an Induced Voltage difference of the nonoverlapping coil sets, whereas the position of the EV is determined by an Induced Voltage of the nonoverlapping coil sets. A sensing circuit, which has a variable resistor that is different from the conventional overlapping coil for MOD, can make the Induced Voltage difference zero even when the magnetic flux distribution is distorted by moving the pick-up coil. The proposed nonoverlapping coil sets with the sensing circuit have been demonstrated by simulations and experiments. When metallic coins and aluminum sheets are located on the power supply coil, the Induced Voltage difference of the coil sets, which is ideally zero without metal objects, significantly increases to 62.8 and 450 mV, respectively, which is more than ten times the value without metal objects throughout experiments. In addition, when the pick-up coil approaches the power supply coil, Induced Voltage of each coil set increased roughly 1.6 times at 10 cm air gap.
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metal object detection system with parallel mistuned resonant circuits and nullifying Induced Voltage for wireless ev chargers
2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia), 2018Co-Authors: Seog Y Jeong, Jun H. Park, Van X Thai, Chun T RimAbstract:In this paper, a metal object detection (MOD) system, a kind of foreign object detection (FOD), which is based on mistuned resonant circuits and utilizes variation of self-inductance of a sensing pattern, is newly proposed for wireless electric vehicle (EV) chargers. The sensing pattern that consists of multiple loop coil sets is mounted on the transmitting (Tx) pad of an EV charger, where a loop coil set has two coils connected in series with opposite polarity to cancel out the Induced Voltage generated by the Tx coil. Variation of self-inductance of the loop coil set is detected by a parallel-resonant circuit, driven by a current source and operating at near 1 MHz. To increase the detection sensitivity of the proposed MOD system, instead of an exact resonant frequency, a mistuned operating frequency near the −3dB point is utilized for the parallel-resonant circuit. Through simulations and experiments, it is found that the proposed MOD system detects not only horizontal but also standing upright metal objects. A prototype MOD system, operating at 85 kHz to satisfy the standard J2954, was fabricated to verify its feasibility. The results showed that output Voltage change of the proposed MOD system becomes 22.7 % for a piece of aluminum foil of 3 × 3 cm2 and 40.9 % for 100 Korean Won coin, respectively.
C Wang - One of the best experts on this subject based on the ideXlab platform.
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analysis and reduction of on load dc winding Induced Voltage in wound field switched flux machines
IEEE Transactions on Industrial Electronics, 2020Co-Authors: C Wang, J C Mipo, Sophie Personnaz, P FarahAbstract:DC winding Induced Voltage pulsation in wound field switched flux (WFSF) machines causes dc winding current ripple and field excitation fluctuation, challenges the dc power source, and deteriorates the control performance. Hence, reducing this pulsation is important in the design of a WFSF machine. In this paper, based on the analytical models, rotor skewing and rotor iron piece pairing are proposed and comparatively investigated by the finite-element (FE) method to reduce the on-load dc winding Induced Voltage in WFSF machines having partitioned stators and concentrated ac windings. FE results show that peak-to-peak value of the on-load dc winding Induced Voltage in the analyzed 12/10-pole partitioned stator WFSF (PS-WFSF) machines can be reduced by 78.42% or 77.16% by using rotor skewing or rotor pairing, respectively, while the torque density can be maintained by >90%. As for the 12/11-, 12/13-, and 12/14-pole PS-WFSF machines, by using rotor iron piece inner arc pairing, the on-load dc winding Induced Voltage can be reduced by 64.11%, 52.12%, and 76.49%, respectively, while the torque density can be maintained by more than 90%. Prototypes are built and tested to verify the analytical and FE results.
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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: 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.
Z Q Zhu - One of the best experts on this subject based on the ideXlab platform.
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influence of stator slot and rotor pole number combination on field winding Induced Voltage ripple in hybrid excitation switched flux machine
IEEE Transactions on Energy Conversion, 2021Co-Authors: Xiaoyong Sun, Z Q Zhu, Shun Cai, Lu Wang, F R Wei, Bo ShaoAbstract:The Induced Voltage ripple in DC field windings can cause many problems in hybrid excitation machines (HEMs). It can generate ripple current in field winding, thus causing unsteady magnetic field excitation and hence additional torque ripple and losses. Besides, the torque and power density of hybrid excitation machines may be deteriorated as a result of the influence of the Induced Voltage ripple on field winding's excitation circuit, particularly under high-speed conditions. Based on a hybrid excitation switched flux machine (HESFM), the influence of stator slot and rotor pole number combination on no-load and on-load field winding Induced Voltage ripples are studied and compared by the finite element method (FEM). It reveals that the harmonic content and thus the peak-to-peak value of the field winding Induced Voltage ripple are closely related to the stator slot and rotor pole number combination at both no-load and on-load operating conditions. The FEM calculations are verified by experiments on a prototype HESFM.
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reduction of open circuit dc winding Induced Voltage and torque pulsation in the wound field switched flux machine by stator axial pairing of tooth tips
International Conference on Electrical Machines, 2020Co-Authors: Wentao Zhang, Wei Hua, Z Q ZhuAbstract:In this paper, stator axial pairing of tooth-tips is proposed to suppress the DC winding Induced Voltage and torque pulsation in the wound field (WF) switched flux (WFSF) machine. The stator is divided into two segments axially, whilst two segments have different arc of tooth-tips. The proposed technique can suppress the rated on-load torque ripple from 17.91% to 6.99%, reduce the peak-to-peak value of cogging torque by 90.1% from 5.14 Nm to 0.48 Nm, and reduce the opencircuit DC winding Induced Voltage by 84.4% from 39.79 V to 6.21 V. Although the efficiency of the machine is slightly reduced from 81.5% to 80.7%, the average torque can be maintained by >95%.
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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.
Wanlin Guo - One of the best experts on this subject based on the ideXlab platform.
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exceptional high seebeck coefficient and gas flow Induced Voltage in multilayer graphene
Applied Physics Letters, 2012Co-Authors: Jun Yin, Jianxin Zhou, Qin Wang, Wanlin GuoAbstract:Seebeck coefficient of graphene is an important parameter for defining its thermoelectric performance and thus practical applications, such as gas-flow-Induced Voltage. Here, we find a unique layer-dependence of the graphene Seebeck coefficient that exceptionally increases with increasing thickness to reach a peak value at six layers that is ∼77% higher than monolayer and ∼296% higher than graphite, unlike the monotonic decrease in electric resistance. However, the gas flow-Induced Voltage is significantly higher in 2, 4, 5, 6, and 7 layered graphene samples than in 1, 3, and 8 layered ones, against the prevailing wisdom that it should be proportional to Seebeck coefficient.
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exceptional high seebeck coefficient and gas flow Induced Voltage in multilayer graphene
arXiv: Mesoscale and Nanoscale Physics, 2012Co-Authors: Jun Yin, Jianxin Zhou, Qin Wang, Wanlin GuoAbstract:Monolayer graphene shows Seebeck coefficient several times and gas-flow-Induced Voltage twenty times higher than that of bulk graphite. Here we find that the Seebeck coefficient of multilayer graphene increases monotonically with increasing layer and reaches its peak value at hexa-layer ~77% higher than for monolayer and then decreases, although the electric resistance decreases monotonically with increasing layer. The flow-Induced Voltage is significantly higher in 2, 4, 5, 6, 7 layered graphene than in 1, 3, 8 layered one, against the prevailing view that it should be proportional to Seebeck coefficient. These thickness effects are also in sharp contrast to that in continuous aluminum nanofilms.