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Online Estimation of Rotor Temperature in Induction Motors Based on Parameter Identification

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Online Estimation of Rotor Temperature in Induction Motors B...

IEEE Energy Conversion Congress and Exposition

作者： Haisen Zhao Hassan H. Eldeeb Jinyu Wang Yang Zhan Guorui Xu Osama A. Mohammed State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University (NCEPU) Beijing China Department of Electrical and Computer Engineering Florida International University Miami FL USA

This study proposes an in-service induction machine (IM) rotor's temperature estimation method. The proposed method is based on the noninvasive measurements of current and potential sensors. First of all, using the rotor slot harmonics superimposed on the stator's current, the rotor speed is extracted. Secondly, the first few cycles of the IM's starting process is used to mimic the locked-rotor test condition while the IM is in-service. Using the aforementioned analogy, the initial value of the rotor's resistance is calculated directly. A merit of the proposed method is that it requires significantly less time to estimate the rotor's resistance compared to the traditional methods in literature, and convergence speed of the parameter identification can be improved significantly. Consequently, the rotor resistance can be on-line identified via the Model Reference Adaptive (MRA) method. Thereby, the rotor temperature is calculated by the resistance-temperature linear relation of metals. Experimental validation is performed on a 5.5kW motor, and the estimated results agreed with the tested ones.

关键词： Rotors Resistance Harmonic analysis Stators Temperature sensors Induction motors Parameter estimation

Claimed detection of PH3 in the clouds of Venus is consistent with mesospheric SO2

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arXiv 2021年

作者： Lincowski, Andrew P. Meadows, Victoria S. Crisp, David Akins, Alex B. Schwieterman, Edward W. Arney, Giada N. Wong, Michael L. Steffes, Paul G. Parenteau, M. Niki Domagal-Goldman, Shawn Department of Astronomy and Astrobiology Program University of Washington Box 351580 SeattleWA98195 United States NASA Nexus for Exoplanet System Science Virtual Planetary Laboratory Team University of Washington Box 351580 SeattleWA98195 United States Jet Propulsion Laboratory California Institute of Technology Earth and Space Sciences Division PasadenaCA91011 United States Jet Propulsion Laboratory California Institute of Technology Instruments Division PasadenaCA91011 United States Department of Earth and Planetary Sciences University of California RiversideCA92521 United States Blue Marble Space Institute of Science SeattleWA United States NASA/Goddard Space Flight Center GreenbeltMD20771 United States School of Electrical and Computer Engineering Georgia Institute of Technology AtlantaGA30332-0250 United States MS 239-4 Space Science Division NASA Ames Research Center Moffett FieldCA United States

The observation of a 266.94 GHz feature in the Venus spectrum has been attributed to PH3 in the Venus clouds, suggesting unexpected geological, chemical or even biological processes. Since both PH3 and SO2 are spectrally active near 266.94 GHz, the contribution to this line from SO2 must be determined before it can be attributed, in whole or part, to PH3. An undetected SO2 reference line, interpreted as an unexpectedly low SO2 abundance, suggested that the 266.94 GHz feature could be attributed primarily to PH3. However, the low SO2 and the inference that PH3 was in the cloud deck posed an apparent contradiction. Here we use a radiative transfer model to analyze the PH3 discovery, and explore the detectability of different vertical distributions of PH3 and SO2. We find that the 266.94 GHz line does not originate in the clouds, but above 80 km in the Venus mesosphere. This level of line formation is inconsistent with chemical modeling that assumes generation of PH3 in the Venus clouds. Given the extremely short chemical lifetime of PH3 in the Venus mesosphere, an implausibly high source flux would be needed to maintain the observed value of 20±10 ppb. We find that typical Venus SO2 vertical distributions and abundances fit the JCMT 266.94 GHz feature, and the resulting SO2 reference line at 267.54 GHz would have remained undetectable in the ALMA data due to line dilution. We conclude that nominal mesospheric SO2 is a more plausible explanation for the JCMT and ALMA data than PH3 © 2021, CC BY.

关键词： Radiative transfer

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arXiv 2020年

作者： Li, Jiashuo Zhou, Sili Wei, Wendong Qi, Jianchuan Li, Yumeng Chen, Bin Zhang, Ning Guan, Dabo Qian, Haoqi Wu, Xiaohui Miao, Jiawen Chen, Long Liang, Sai Feng, Kuishuang Institute of Blue and Green Development Shandong University Weihai264209 State Key Laboratory of Coal Combustion School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan430074 China School of International and Public Affairs Shanghai Jiao Tong University Shanghai200030 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Beijing Normal University Beijing100875 China Laboratory of Anthropogenic Systems Ecology College of Engineering Peking University Beijing100871 China Department of Earth System Science Tsinghua University Beijing100871 China Institute for Global Public Policy Fudan University Shanghai200433 China School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology Shanghai200093 China Key Laboratory of Geographic Information Science Ministry of Education School of Geographic Sciences East China Normal University Shanghai200241 China

China has implemented retrofitting measures in coal-fired power plants (CFPPs) to reduce air pollution through small unit shutdown (SUS), the installation of air pollution control devices (APCDs) and power generation efficiency (PGE) improvement. The reductions in highly toxic Hg emissions and their related health impacts by these measures have not been well studied. To refine mitigation options, we evaluated the health benefits of reduced Hg emissions via retrofitting measures during China's 12th Five-Year Plan by combining plant-level Hg emission inventories with the China Hg Risk Source-Tracking Model. We found that the measures reduced Hg emissions by 23.5 tons (approximately 1/5 of that from CFPPs in 2010), preventing 0.0021 points of per-foetus intelligence quotient (IQ) decrements and 114 deaths from fatal heart attacks. These benefits were dominated by CFPP shutdowns and APCD installations. Provincial health benefits were largely attributable to Hg reductions in other regions. We also demonstrated the necessity of considering human health impacts, rather than just Hg emission reductions, in selecting Hg control devices. This study also suggests that Hg control strategies should consider various factors, such as CFPP locations, population densities and trade-offs between reductions of total Hg (THg) and Hg2+. Copyright © 2020, The Authors. All rights reserved.

关键词： Fossil fuel power plants

Frontoparietal connectivity neurofeedback training for promotion of working memory: An fNIRS study in healthy male participants

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arXiv 2020年

作者： Xia, Meiyun Xu, Pengfei Yang, Yuanbin Jiang, Wenyu Wang, Zehua Gu, Xiaolei Yang, Mingxi Li, Deyu Li, Shuyu Dong, Guijun Wang, Ling Wang, Daifa School of Biological Science and Medical Engineering Beihang University Beijing100083 China College of Computer Science Sichuan Normal University Chengdu610101 China Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing100083 China State Key Laboratory of Virtual Reality Technology and System Beihang University Beijing100083 China Department of Rehabilitation Medicine Wangjing Hospital China Academy of Chinese Medical Sciences Beijing100102 China Department of Neurological Rehabilitation Guangxi Jiangbin Hospital Nanning530021 China School of Sports and Health Shandong Sport University Jinan250102 China

Neurofeedback cognitive training is a promising tool used to promote cognitive functions effectively and efficiently. In this study, we investigated a novel functional near-infrared spectroscopy (fNIRS)based frontoparietal functional connectivity (FC) neurofeedback training paradigm related to working memory, involving healthy adults. Compared with conventional cognitive training studies, we chose the frontoparietal network, a key brain region for cognitive function modulation, as neurofeedback, yielding a strong targeting effect. In the experiment, 10 participants (test group) received three cognitive training sessions of 15 min using fNIRS-based frontoparietal FC as neurofeedback, and another 10 participants served as the control group. Frontoparietal FC was significantly increased in the test group (p = 0.03), and the cognitive functions (memory and attention) were significantly promoted compared with the control group (accuracy of 3-back test: p = 0.0005, reaction time of 3-back test: p = 0.0009). After additional validations on long-term training effect and on different patient populations, the proposed method exhibited considerable potential to be developed as a fast, effective, and widespread training approach for cognitive function enhancement. Copyright © 2020, The Authors. All rights reserved.

关键词： Brain

Discriminative Marginalized Least Squares Regression for Hyperspectral Image Classification

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Discriminative Marginalized Least Squares Regression for Hyp...

Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing, WHISPERS

作者： Yuxiang Zhang Wei Li Qian Du Xu Sun College of Information Science & Technology Beijing University of Chemical Technology School of Information and Electronics Beijing Institute of Technology Beijing China Department of Electrical and Computer Engineering Mississippi State University MS USA Key laboratory of Digital Earth Science Institute of Remote Sensing and Digital Earth Beijing China

ISBN: (纸本)9781728152950

Least squares regression (LSR)-based classifiers are rarely used for hyperspectral image classification. The reason is that their limited projections result in the loss of much discriminant information, and they focus only on exactly fitting samples to the label matrix while ignoring the problem of label overfitting. To solve this issue, discriminative marginalized least squares regression (DMLSR) is proposed to learn a more discriminative projection matrix with consideration of class separability and data reconstruction ability simultaneously. In the proposed method, Fisher criterion is employed to avoid the overfitting problem and enhance class separability; furthermore, a data-reconstruction constraint is imposed to preserve more discriminant information on limited projections, thereby enhancing classification performance. Experimental results on two hyperspectral datasets demonstrate that the proposed method significantly outperforms some state-of-the-art classifiers.

关键词： Training Hyperspectral imaging Image classification Image reconstruction Support vector machines Fitting

Image reconstruction with low-rankness and self-consistency of k-space data in parallel MRI

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arXiv 2019年

作者： Zhang, Xinlin Guo, Di Huang, Yiman Chen, Ying Wang, Liansheng Huang, Feng Qu, Xiaobo Department of Electronic Science Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance School of Electronic Science and Engineering National Model Microelectronics College Xiamen University Xiamen361005 China School of Computer and Information Engineering Fujian Provincial University Key Laboratory of Internet of Things Application Technology Xiamen University of Technology Xiamen361024 China Department of Computer Science School of Information Science and Engineering Xiamen University Xiamen361005 China Neusoft Medical System Shanghai200241 China

Parallel magnetic resonance imaging has served as an effective and widely adopted technique for accelerating scans. The advent of sparse sampling offers aggressive acceleration, allowing flexible sampling and better reconstruction. Nevertheless, faithfully reconstructing the image from limited data still poses a challenging task. Recent low-rank reconstruction methods exhibit superiority in providing a high-quality image. However, none of them employ the routinely acquired calibration data for improving image quality in parallel magnetic resonance imaging. In this work, an image reconstruction approach named STDLR-SPIRiT was proposed to explore the simultaneous two-directional low-rankness (STDLR) in the k-space data and to mine the data correlation from multiple receiver coils with the iterative self-consistent parallel imaging reconstruction (SPIRiT). The reconstruction problem was then solved with a singular value decomposition-free numerical algorithm. Experimental results of phantom and brain imaging data show that the proposed method outperforms the state-of-the-art methods in terms of suppressing artifacts and achieving the lowest error. Moreover, the proposed method exhibits robust reconstruction even when the auto-calibration signals are limited in parallel imaging. Overall the proposed method can be exploited to achieve better image quality for accelerated parallel magnetic resonance imaging. Copyright © 2019, The Authors. All rights reserved.

关键词： Magnetic resonance imaging

Study on Subsynchronous Resonance Damping Control for Series-Compensated DFIG-Based Wind Farm

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Study on Subsynchronous Resonance Damping Control for Series...

Sustainable Power and Energy Conference (iSPEC)

作者： Chao Luo Qi Guo Xiangning Xiao A.M Gole Mengjun Liao State Key Laboratory of HVDC Electric Power Research Institute State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China Electrical and Computer Engineering Department University of Manitoba Winnipeg Canada

ISBN: (纸本)9781728149318

Subsynchronous Resonance (SSR) is a potential threat for long distance power transmission from doubly fed induction generator (DFIG) based wind farms with fixed series compensation (FSC). In this paper, subsynchronous resonance damping control (SSRDC) strategy based on shunt voltage source converter is proposed. Taking account of different series compensation levels and wind speeds, several potential inputs to the SSRDC are investigated. SSRDC control parameters are determined via root locus techniques to ensure the system stability of subsynchronous modes. Considering implementation feasibility in practical project and stability of supersynchronous modes, an enhanced SSRDC is proposed. Impact of transmission line and DFIG parameters and the reactive power compensation to the mitigation effect is investigated. Time domain simulation using PSCAD/EMTDC are carried out to validate the effectiveness of the SSRDC.

关键词： Doubly fed induction generator (DFIG) fixed series capacitor compensation (FSC) Subsynchronous Resonance (SSR) voltage source converter (VSC) Subsynchronous Resonance damping controller Wind farms subsynchronous resonance damped control system stability power transmission reactive compensation series compensation double-fed induction generator TIME-DOMAIN Transmission Lines Compensation depth

SPA-SSD: Exploit Heterogeneity and Parallelism of 3D SLC-TLC Hybrid SSD to Improve Write Performance

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SPA-SSD: Exploit Heterogeneity and Parallelism of 3D SLC-TLC...

IEEE International Conference on computer Design: VLSI in computers and Processors, (ICCD)

作者： Wenhui Zhang Qiang Cao Hong Jiang Jie Yao Yuanyuan Dong Puyuan Yang Wuhan National Laboratory for Optoelectronics Key Laboratory of Information Storage System Engineering Research Center of Data Storage Systems and Technology Ministry of Education of China Huazhong University of Science and Technology Wuhan China Department of Computer Science and Engineering University of Texas at Arlington Arlington Texas School of Computer Science and Technology Huazhong University of Science and Technology Wuhan China Alibaba Group. Hangzhou China

To address the write performance problem suffered by MLC/TLC flash, researchers have proposed hybrid SSD that aims to combine the strengths of SLC flash, used as the write-buffer zone for its superior write performance, and MLC/TLC flash, as the capacity zone for its high storage density. While leveraging SLC as a physical write-buffer zone is proven effective in traditional 2D hybrid SSDs, how to effectively incorporate SLC into a 3D-stacked TLC to form a hybrid SSD has not been studied to the best of our knowledge. Yet this is a timely and important performance issue for 3D-stacked TLC given its one-shot programming scheme that results in much worse write performance than the programming scheme in 2D TLC where pages are associated with different bits of a cell and programmed in sequence separately. We believe that naively adopting the two-physical-zone approach to 3D hybrid SSD will miss a great opportunity for performance optimization because it ignores the inherent four-level parallelism (channel/chip/die/plane) of the flash chip array. To this end, we propose in this paper an SLC and Parallelism Aware hybrid SSD (SPA-SSD) to take full advantages of SLC's superior write performance, the internal multi-level parallelism of SSD, and the high storage density of 3D-stacked TLC flash. Two novel techniques enable SPA-SSD to be highly effective: (1) Type-Parallelism Joint Page Allocation (TPJ-PA), which allocates pages for write transactions according to not only available SLC pages but also parallelism to maximize resource utilization within the hybrid SSD, and (2) Queue-length and Parallelism Constrained Data Migration (QPC-DM), which triggers data migration without degrading user write performance by analyzing the device queue length and available flash resources. To evaluate performance of SPA-SSD, a hybrid SSD simulator, called HybridSim, is developed based on MQSim. Experimental results on HybridSim show that TPJ-PA improves write throughput by 60%, while QPC-DM

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Approaches to improving the detection sensitivity of optical modulation based radiation detection method for positron emission tomography

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Approaches to improving the detection sensitivity of optical...

IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Yuli Wang Li Tao Craig S. Levin Jianfeng Xu Electrical and computer Engineering University of California Santa Cruz Santa Cruz USA Department of Electrical Engineering Stanford University Stanford CA USA Departments of Radiology Physics Electrical Engineering and Bioengineering Stanford University Stanford CA USA State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong Univ. of Sci. and Tech. Wuhan China

ISBN: (数字)9781728141640

ISBN: (纸本)9781728141657

In this paper, two approaches to improving the detection sensitivity of the optical modulation based radiation detection method for positron emission tomography (PET) have been investigated utilizing BSO, CdTe and PbBiGa as detector crystals. We first explored the magic angle of our two-crossed-polarizers based setup, of which the detection sensitivity could be improved by 15% at the magic angle. We then investigated the dependence of the detection sensitivity on the electric field distribution as well as on the crystal bias voltage with CdTe and PbBiGa crystals. Both the electric field distribution (i.e., electrode pattern) and applied bias voltage could affect the magnitude of the modulation signal and thus affect the setup's detection sensitivity. From our findings, we can conclude that a more concentrated electric field distribution (or a smaller electrode) could contribute to a better detection sensitivity. Besides, the detection sensitivity increases linearly with the bias voltage for all detector crystals and thus we could improve the detection sensitivity by adding higher bias voltage to the detector crystal.

关键词： Crystals Sensitivity Electrodes Optical modulation Detectors II-VI semiconductor materials