The Experts below are selected from a list of 1935 Experts worldwide ranked by ideXlab platform
Bo Wang - One of the best experts on this subject based on the ideXlab platform.
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Flux-Weakening Control for Induction Motor in Voltage Extension Region: Torque Analysis and Dynamic Performance Improvement
IEEE Transactions on Industrial Electronics, 2018Co-Authors: Zhen Dong, Bo WangAbstract:Flux-weakening control for induction motor (IM) in voltage extension region (outside the Inscribed Circle but in the hexagon) is meaningful to yield a further maximum torque. However, as the voltage-limit trajectory migrates out of the Inscribed Circle, torque ripple becomes more severe. Meanwhile, the insufficient voltage margin results in the degradation of current dynamic performance in transition period (from base speed region to flux-weakening region), especially in harsh conditions, e.g., a step speed command. To address the problems above, this paper gives a quantitative analysis of the torque ripple and an explicit discussion on the current dynamic performance. A novel “Voltage Reference Adjustable” flux-weakening controller with “Self-Locking Limit Block” (SLLB) is proposed. There are two advantages. The first is the capability to operate in any voltage extension regions, offering a tradeoff between obtaining the maximum torque and suppressing the torque ripple. The second is an optimized voltage distribution, achieving a better track characteristic of d - and q -axis currents with the help of triggered SLLB in transition period. Experimental results on a commercial IM control system verify the validity of the proposed scheme.
Fei Xing - One of the best experts on this subject based on the ideXlab platform.
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CAD/Graphics - Robust Algorithm for Detecting the Maximum Inscribed Circle
2007 10th IEEE International Conference on Computer-Aided Design and Computer Graphics, 2007Co-Authors: Jibing Zhao, Hongyou Bian, Fei XingAbstract:In this paper, we propose a new robust algorithm for the detection of the maximum Inscribed Circles (MIC) in images. We first use a vector distance transformation (VDT) strategy to create a distance field. Then, we globally search the maximal value in distance field to extract the medial axes. Finally, we give a procedure to determine the center and radius of MIC. Our experimental results show indeed that new algorithm is capable of detecting the MIC with excellent accuracy and high efficiency under various image conditions.
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Robust Algorithm for Detecting the Maximum Inscribed Circle
2007 10th IEEE International Conference on Computer-Aided Design and Computer Graphics, 2007Co-Authors: Jibing Zhao, Hongyou Bian, Fei XingAbstract:In this paper, we propose a new robust algorithm for the detection of the maximum Inscribed Circles (MIC) in images. We first use a vector distance transformation (VDT) strategy to create a distance field. Then, we globally search the maximal value in distance field to extract the medial axes. Finally, we give a procedure to determine the center and radius of MIC. Our experimental results show indeed that new algorithm is capable of detecting the MIC with excellent accuracy and high efficiency under various image conditions.
Zhen Dong - One of the best experts on this subject based on the ideXlab platform.
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Flux-Weakening Control for Induction Motor in Voltage Extension Region: Torque Analysis and Dynamic Performance Improvement
IEEE Transactions on Industrial Electronics, 2018Co-Authors: Zhen Dong, Bo WangAbstract:Flux-weakening control for induction motor (IM) in voltage extension region (outside the Inscribed Circle but in the hexagon) is meaningful to yield a further maximum torque. However, as the voltage-limit trajectory migrates out of the Inscribed Circle, torque ripple becomes more severe. Meanwhile, the insufficient voltage margin results in the degradation of current dynamic performance in transition period (from base speed region to flux-weakening region), especially in harsh conditions, e.g., a step speed command. To address the problems above, this paper gives a quantitative analysis of the torque ripple and an explicit discussion on the current dynamic performance. A novel “Voltage Reference Adjustable” flux-weakening controller with “Self-Locking Limit Block” (SLLB) is proposed. There are two advantages. The first is the capability to operate in any voltage extension regions, offering a tradeoff between obtaining the maximum torque and suppressing the torque ripple. The second is an optimized voltage distribution, achieving a better track characteristic of d - and q -axis currents with the help of triggered SLLB in transition period. Experimental results on a commercial IM control system verify the validity of the proposed scheme.
Zhaoyao Shi - One of the best experts on this subject based on the ideXlab platform.
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The relationship between the minimum zone Circle and the maximum Inscribed Circle and the minimum circumscribed Circle
Precision Engineering, 2009Co-Authors: Zhaoyao ShiAbstract:Following the minimum zone criterion set forth in the current ANSI and ISO standards, evaluation of roundness error is formulated as a non-differentiable unconstrained optimization problem and hard to handle. The maximum Inscribed Circle and minimum circumscribed Circle are all easily solved by iterative comparisons, so the relationship between the minimum zone Circle and maximum Inscribed Circle, minimum circumscribed Circle is proposed to solve efficiently the minimum zone problem. Based on the known minimum zone Circle, the maximum Inscribed Circle and minimum circumscribed Circle can be easily determined. The relationship is implemented and validated with the data available in the literature.
Raj Kumar - One of the best experts on this subject based on the ideXlab platform.
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Design of Inscribed Circle Apollo UWB Fractal Antenna with Modified Groundplane
Indian journal of science and technology, 2012Co-Authors: Tejal R. Mehetre, Raj KumarAbstract:In this paper, we have achieved two ultra wideband antennas by applying fractal geometry with co-planar waveguide (CPW) feeding technique. These antennasare designed on dielectric substrate er= 4.3 and thickness h = 1.53 mm. The return loss of first antenna design is achieved a good input impedance matching throughout the pass band from 2.5 GHz to 11GHz. The second antenna offers the impedance matching from frequency range 2.1GHz to 12GHz. The proposed antennas can provide an impedance bandwidth more than100% at VSWR
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design of Inscribed Circle apollo uwb fractal antenna with modified groundplane
Indian journal of science and technology, 2012Co-Authors: Tejal R. Mehetre, Raj KumarAbstract:In this paper, we have achieved two ultra wideband antennas by applying fractal geometry with co-planar waveguide (CPW) feeding technique. These antennasare designed on dielectric substrate er= 4.3 and thickness h = 1.53 mm. The return loss of first antenna design is achieved a good input impedance matching throughout the pass band from 2.5 GHz to 11GHz. The second antenna offers the impedance matching from frequency range 2.1GHz to 12GHz. The proposed antennas can provide an impedance bandwidth more than100% at VSWR<2. Second antenna helps to increase impedance bandwidth by reducing the ground plane. The simulated radiation pattern of antenna is nearly omni-directional. Such type of antenna can be useful for mobile and wireless communication.