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Self-adjusting strategy based on rotating injection for sensorless control of high-power PMSM drives
Xiaofan Wang,Xiaochun Fang,Zhi Wang,Zhihong Zhong,Yizhi Wang,Fei Lin,Zhongping Yang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
As a sensorless control method suitable for permanent magnet synchronous motor (PMSM) at lowspeed, rotating high-frequency injection method will face some special problems in high power applications. On the one hand, the low switching frequency limits the injected signal frequency, which is very close to the fundamental frequency. On the other hand, under heavy load conditions, the fundamental current amplitude is several hundred times of the negative sequence current. This will result in difficulty in signal extraction. In this paper, current spectrum is analyzed quantitatively based on the parameters of PMSM drive for rail vehicles, which illustrates the limitations of conventional bandpass filters. A method based on self-adjusting filter is proposed. The negative sequence current is successfully extracted, and the precise rotor position is obtained under the condition of variable speed and variable load. Based on a fullscale test platform the effectiveness of the proposed method is proved.
Xue-Jun Zhao,Zhong-Peng Li,Jun-Hong Wang,Xiang-Ming Xing,Zhenyong Wang,Lin Wang,Zhong-Hua Wang 대한수의학회 2015 Journal of Veterinary Science Vol.16 No.4
To evaluate the effects of chelated Zn/Cu/Mn on redox status, immune responses and hoof health in lactating Holstein cows, 48 head in early lactation were divided into healthy or lame groups according to their gait score. Cows were fed the same amount of Zn/Cu/Mn as sulfate salts or in chelated forms for 180 days, and foot-and-mouth disease (FMD) vaccine was injected at day 90. The results showed that lame cows had lower antioxidant function, serum Zn/Mn levels, hair Cu levels, and hoof hardness. Moreover, increased antioxidant status, FMD antibody titers, serum and hair levels of Zn/Cu/Mn, and hoof hardness and decreased milk fat percent and arthritis biomarkers were observed in cows fed chelated Zn/Cu/Mn. In summary, supplementation with chelated Zn/Cu/Mn improved antioxidant status and immune responses, reduced arthritis biomarkers, and increased accumulation of Zn/Cu/Mn in the body and hoof hardness in dairy cows.
An Analytical Solution for Voltage Stability Studies Incorporating Wind Power
Lin, Yu-Zhang,Shi, Li-Bao,Yao, Liang-Zhong,Ni, Yi-Xin,Qin, Shi-Yao,Wang, Rui-Ming,Zhang, Jin-Ping The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3
Voltage stability is one of the most critical security issues which has not yet been well resolved to date. In this paper, an analytical method called PQ plane analysis with consideration of the reactive power capability of wind turbine generator and the wake effect of wind farm is proposed for voltage stability study. Two voltage stability indices based on the proposed PQ plane analysis method incorporating the uncertainties of load-increasing direction and wind generation are designed and implemented. Cases studies are conducted to investigate the impacts of wind power incorporation with different control modes. Simulation results demonstrate that the constant voltage control based on reactive power capability significantly enhances voltage stability in comparison of the conventional constant power factor control. Some meaningful conclusions are obtained.
Zhong-Yi Cai,Lin-Lin Li,Mi Wang,Ming-Zhe Li 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
Continuous roll forming (CRF) is a process to form three-dimensional surface based on the rolling deformation of sheet metal. Unliketraditional rolling process where the working rolls are straight and rigid, two small-diameter bendable forming rolls are used herein,and the sheet metal is bent in longitudinal and transverse directions simultaneously after it is compressed between a pair of bendedrolls. The formed surface is controlled by the curved shapes of the forming rolls and the gap between the two rolls, and the roll gapis the crucial parameter of CRF process. In this paper, the required velocity distribution of material across the exit of roll gap forthe formation of a smooth surface is analyzed, the formulations for the CRF process design is derived and a method to predict thelongitudinal bending deformation generated by roll gap is presented. Finally, the validity of the presented methods and theoreticalmodels are demonstrated by numerical simulations and CRF tests for typical surface parts.
Power Distribution and Coordinated Control for a Power Split Hybrid Electric Bus
Wang, Feng,Zhong, Hu,Ma, Zi-Lin,Mao, Xiao-Jian,Zhuo, Bin The Korean Institute of Electrical Engineers 2008 Journal of Electrical Engineering & Technology Vol.3 No.4
The power distribution is proposed to determine the target operating points of the system components as the basis for maximal the efficiency of the overall system for a power split dual electric machine hybrid electric bus. The coordinated control is constructed on the basis of the power distribution. The basic coordinated control is implemented to satisfy the driver's power demand, in which both the dynamic characteristics of the engine and the dual electric machine are explicitly taken into account. Moreover, the improved coordinated control is suggested to suppress engine dynamic operation and rich fuel injection.
Improvement of the Shearing Behaviour of Loess Using Recycled Straw Fiber Reinforcement
Zhong-Fei Xue,Wen-Chieh Cheng,Lin Wang,Geyang Song 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.9
Reinforcing structural members and construction materials using recycled fibers has become popular in the past decades due to sustainable development concerns. The recycled fibers as soil reinforcement elements contribute to the increase in shear strength by distributing stresses exerted in the soil along the length of the recycled fibers. Loess, widely spread over the Chinese Loess Plateau, is featured with metastable structure, large porosity, and high water sensitivity. This study presents the results of applying the large-scale stress-controlled direct shear tests on the recycled straw fiber-reinforced loess. The formation mechanism of shearing behaviour enhancement of the loess by straw fiber inclusion is revealed. The associated strain-hardening behaviour can be manifested using the dilation angle or the difference in friction angle between the large-displacement friction angle and the peak friction angle. Further, the shear strength using the displacement-controlled direct shear tests presents good correspondence with that using the stress-controlled direct shear tests. The test results explore the potential of using the recycled straw fiber-reinforced loess to protect the fragile loess environment in the northwest of China.
Wang, Xi-Wen,Zhong, Tian-Yu,Xiong, Yun-Hui,Lin, Hai-Bo,Liu, Qing-Yi Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8
Purpose: Any association between the CYP1A1 Ile462Val polymorphism and endometrial cancer risk remains inconclusive. For a more precise estimate, we performed the present meta-analysis. Methods: PUBMED, OVID and EMBASE were searched for the studies which met inclusion criteria. Data in all eligible studies were evaluated and extracted by two authors independently. The meta-analysis estimated pooled odds ratio (OR) with 95% confidence interval (CI) for endometrial cancer risk attributable to the CYP1A1 Ile462Val polymorphism. Results: A total of 7 studies were included in this meta-analysis. The results indicated no association between endometrial cancer risk and the CYP1A1 Ile462Val polymorphism (for Val vs Ile allele model [OR 1.09, 95% CI 0.73-1.62]; for Val.Val vs Ile.Ile genotype model [OR 1.54, 95% CI 0.56-4.23]; for (Ile.Val + Val.Val) vs Ile.Ile genotpye model [OR 1.08, 95% CI 0.71-1.63]; for Val.Val vs (Ile.Ile + Ile.Val) genotype model [OR 1.46, 95% CI 0.53-4.04]). Conclusions: This meta-analysis suggests that there is no association between endometrial cancer risk and the CYP1A1 Ile462Val polymorphism.
Mesocarbon microbead densified matrix graphite A3-3 for fuel elements in molten salt reactors
Wang, Haoran,Xu, Liujun,Zhong, Yajuan,Li, Xiaoyun,Tang, Hui,Zhang, Feng,Yang, Xu,Lin, Jun,Zhu, Zhiyong,You, Yan,Lu, Junqiang,Zhu, Libing Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5
This study aims to provide microstructural characterization for the matrix graphite which molten salt reactors (MSRs) use, and improve resistance to molten salt infiltration of the matrix graphite for fuel elements. Mesocarbon microbeads (MCMB) densified matrix graphite A3-3 (MDG) was prepared by a quasi-isostatic pressure process. After densification by MCMBs with average particle sizes of 2, 10, and 16 ㎛, the pore diameter of A3-3 decreased from 924 nm to 484 nm, 532 nm, and 778 nm, respectively. Through scanning electron microscopy, the cross-section energy spectrum and time-of-flight secondary ion mass spectrometry, resistance levels of the matrix graphite to molten salt infiltration were analyzed. The results demonstrate that adding a certain proportion of MCMB powders can improve the anti-infiltration ability of A3-3. Meanwhile, the closer the particle size of MCMB is to the pore diameter of A3-3, the smaller the average pore diameter of MDG and the greater the densification. As a matrix graphite of fuel elements in MSR was involved, the thermal and mechanical properties of matrix graphite MDG were also studied. When densified by the MCMB matrix graphite, MDGs can meet the molten salt anti-infiltration requirements for MSR operation.
Luzhong mutton sheep: inbreeding and selection signatures
Lin Tao,Xiaoyun He,Fengyan Wang,Yingjie Zhong,Linxiang Pan,Xiangyu Wang,Shangquan Gan,Ran Di,Ming-xing Chu 한국축산학회 2020 한국축산학회지 Vol.62 No.6
Intense artificial selection has been imposed to Luzhong mutton sheep population in the past years. Improvements on growth and reproductive performance are two breeding goals in the present herd. Although some progresses were phenotypically observed possibly due to inbreeding induced by strong selection in terms of these traits, the genomic evaluation was poorly understood. Therefore, a high-density SNP array was used to characterize the pattern of runs of homozygosity (ROH), estimate inbreeding and inbreeding depressions on early growth performance and litter size based upon ROH, and scan positive selection signatures of recent population. Consequently, a low inbreeding level was observed which had negative effects on litter size, but not on early growth performance. And 160 genes were under selection, of which some were reported to be linked to several traits of sheep including body weight, litter size, carcass and meat quality, milk yield and composition, fiber quality and health, and the top genes were associated with growth (growth hormone [GH]- growth hormone receptor [GHR]- Insulin-like growth factor 1 [IGF1] axis) and litter size (bone morphogenic proteins [BMPs]-associated). The effectiveness of previous breeding measures was highlighted, but purging selection was proposed to alleviate the inbreeding depression on litter size, providing some genomic insights to breeding management of Luzhong mutton sheep.