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MTPA-based high-frequency square wave voltage signal injection strategy for IPMSM control
Zhang, Zeyu,Shen, Anwen,Li, Peihe,Luo, Xin,Tang, Qipeng The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.10
This paper proposes a high-frequency (HF) square wave voltage signal injection strategy for interior permanent magnet synchronous motor (IPMSM) maximum torque per ampere (MTPA) drives. Unlike previous methods, this strategy injects a square wave HF signal into the voltage directly regardless of the current loop bandwidth limitations. In addition, the injected frequency can surpass the cut-off frequency of the current loop. Therefore, the disturbance caused by the injected signal can be reduced. The process of MTPA operating point adjustment only needs to sample and analyze the current amplitude without additional digital filters. Thus, the dynamic response promotes, and avoids the extra hardware and calculation burden. To decrease the convergence time when the load changes rapidly, an equivalent mathematical model of an IPMSM is employed to provide prior current references. Both simulation and experimental results confirm the validity and feasibility of the proposed strategy.
Printed photonic elements: nanoimprinting and beyond
Zhang, Cheng,Subbaraman, Harish,Li, Qiaochu,Pan, Zeyu,Ok, Jong G.,Ling, Tao,Chung, Chi-Jui,Zhang, Xingyu,Lin, Xiaohui,Chen, Ray T.,Guo, L. Jay Royal Society of Chemistry 2016 Journal of Materials Chemistry C Vol.4 No.23
<P>In order to manufacture large-scale photonic devices of various dimensions at a low cost, a number of patterning techniques have been developed. Nanoimprint lithography is among the most promising given its unique advantages, such as high resolution, fast processing speed, high throughput, compatibility with diverse materials, and low cost. This review covers various aspects of nanoimprint lithography, including its operational principles, material requirements, and different ways of implementation. Nanoimprint lithography facilitates numerous high-performance and low-cost photonic elements, including optical interconnects, sensors, solar cells, and metamaterials. In addition, other related patterning techniques, together with their utilization for photonic device fabrication and their integration with nanoimprint lithography, are briefly discussed.</P>
HDRE: Coverage Hole Detection with Residual Energy in Wireless Sensor Networks
Yun-zhou Zhang,Xiaohua Zhang,Wenyan Fu,Zeyu Wang,Honglei Liu 한국통신학회 2014 Journal of communications and networks Vol.16 No.5
Coverage completeness is an important indicator forquality of service in wireless sensor networks (WSN). Due to limitedenergy and diverse working conditions, the sensor nodes havedifferent lifetimes which often cause network holes. Most of the existingmethods expose large limitation and one-sidedness becausethey generally consider only one aspect, either coverage rate or energyissue. This paper presents a novel method for coverage holedetection with residual energy in randomly deployed wireless sensornetworks. By calculating the life expectancy of working nodesthrough residual energy, we make a trade-off between network repaircost and energy waste. The working nodes with short lifetimeare screened out according to a proper ratio. After that, the locationsof coverage holes can be determined by calculating the jointcoverage probability and the evaluation criteria. Simulation resultshows that compared to those traditional algorithms without considerationof energy problem, our method can effectively maintainthe coverage quality of repairedWSN while enhancing the life spanof WSN at the same time.
A Nonlinear Multiple-target Coverage Protocol Based on Data Integration of Wireless Sensor Networks
Zeyu Sun,Yongsheng Zhang,Chuanfeng Li,Yangjie Cao,Yalin Nie,Yuanbo Li 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.10
In the process of coverage for multiple targets, due to the existence of a large number of redundant data make the effective monitoring area coverage decreased and force the network to consume more energy. Therefore, this paper proposes a multi-target k-coverage preservation protocol. First of all, establish the affiliation between the sensor nodes and target nodes through the network model, present a method to compute the coverage expected value of the monitoring area; secondly, in the network energy conversion, using scheduling mechanism in sensor nodes to attain the network energy balance, and achieve different network coverage quality through different nodes energy conversion. Finally, simulation results show that NMCP can effectively reduce the number of active nodes meeting certain coverage requirements and then improve the network lifetime.
( Zeyu Sun ),( Yongsheng Zhang ),( Xiaofei Xing ),( Houbing Song ),( Huihui Wang ),( Yangjie Cao ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.8
In the process of k-coverage of the target node, there will be a lot of data redundancy forcing the phenomenon of congestion which reduces network communication capability and coverage, and accelerates network energy consumption. Therefore, this paper proposes a novel energy balanced k-coverage control algorithm based on probability model (EBKCCA). The algorithm constructs the coverage network model by using the positional relationship between the nodes. By analyzing the network model, the coverage expected value of nodes and the minimum number of nodes in the monitoring area are given. In terms of energy consumption, this paper gives the proportion of energy conversion functions between working nodes and neighboring nodes. By using the function proportional to schedule low energy nodes, we achieve the energy balance of the whole network and optimizing network resources. The last simulation experiments indicate that this algorithm can not only improve the quality of network coverage, but also completely inhibit the rapid energy consumption of node, and extend the network lifetime.
Low-noise reconstruction method for coded-aperture gamma camera based on multi-layer perceptron
Rui Zhang,Xiaobin Tang,Pin Gong,Peng Wang,Cheng zhou,Xiaoxiang Zhu,Dajian Liang,Zeyu Wang 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.10
Accurate localization of radioactive materials is crucial in homeland security and radiological emergencies. Coded-aperture gamma camera is an interesting solution for such applications and can be developed into portable real-time imaging devices. However, traditional reconstruction methods cannot effectively deal with signal-independent noise, thereby hindering low-noise real-time imaging. In this study, a novel reconstruction method with excellent noise-suppression capability based on a multi-layer perceptron (MLP) is proposed. A coded-aperture gamma camera based on pixel detector and coded-aperture mask was constructed, and the process of radioactive source imaging was simulated. Results showed that the MLP method performs better in noise suppression than the traditional correlation analysis method. When the Co-57 source with an activity of 1 MBq was at 289 different positions within the field of view which correspond to 289 different pixels in the reconstructed image, the average contrast-to-noise ratio (CNR) obtained by the MLP method was 21.82, whereas that obtained by the correlation analysis method was 5.85. The variance in CNR of the MLP method is larger than that of correlation analysis, which means the MLP method has some instability in certain conditions.
Feixia Zhan,Chao Zhang,Shige Wang,Zeyu Zhu,Guang-Chen Jiao,Mingliang Zhao,Li Cao 대한신경과학회 2020 Journal of Clinical Neurology Vol.16 No.2
Background and Purpose Hyperekplexia (HPX), a rare neurogenetic disorder, is classically characterized by neonatal hypertonia, exaggerated startle response provoked by the sudden external stimuli and followed by a shortly general stiffness. Glycine receptor alpha 1 (GLRA1) is the major pathogenic gene of the disease. We described the clinical manifestations of genetically confirmed HPX patients and made a literature review of GLRA1-related HPX to improve the early recognition and prompt the management of the disorder. Methods Extensive clinical evaluations were analyzed in 4 Chinese HPX patients from two unrelated families. Next generation sequencing was conducted in the probands. Sanger sequence and segregation analysis were applied to confirm the findings. Results All four patients including 3 males and 1 female presented with excessive startle reflex, a cautious gait and recurrent falls. Moreover, startle episodes were dramatically improved with the treatment of clonazepam in all cases. Exome sequencing revealed 2 homozygous GLRA1 mutations in the patients. The mutation c.1286T>A p.I429N has been previously reported, while c.754delC p.L252* is novel. Conclusions HPX is a treatable disease, and clonazepam is the drug of choice. By studying and reviewing the disorder, we summarized the phenotype, expanded the genotype spectrum, and discussed the possible pathogenic mechanisms to enhance the understanding and recognition of the disease. Early awareness of the disease is crucial to the prompt and proper administration, as well as the genetic counseling.