Damping for Wind Turbine Electrically Excited Synchronous Generators

Wang Tianyu,Li Guojie,Zhang Yu,Fang Chen 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.4

The electrically excited synchronous generator (EESG) is applied in wind turbine systems recently. In an EESG control system, electrical torque is affected by stator flux and rotor current. So the control system is more complicated than that of the permanent-magnet synchronous generator (PMSG). Thus, the higher demanding of the control system is required especially in case of wind turbine mechanical resonance. In this paper, the mechanism of rotor speed resonant phenomenon is introduced from the viewpoint of mechanics firstly, and the characteristics of an effective damping torque are illustrated through system eigenvalues analysis. Considering the variables are tightly coupled, the four-order small signal equation for torque is derived considering stator and rotor control systems with regulators, and the bode plot of the closed loop transfer function is analyzed. According to the four-order mathematical equation, the stator flux, stator current, and electrical torque responses are derived by torque reference step and ramp in MATLAB from a pure mathematical deduction, which is identical with the responses in PSCAD/EMTDC simulation results. At last, the simulation studies are carried out in PSCAD software package to verify the resonant damping control strategy used in the EESG wind turbine system.

Mental Health Problems of Individuals Under the Stay-Home Policy

Wang Hayson Chenyu,Ting Wenyun,Li Zhijin,Sun Elliot Tianyu,Wang Xiaojun 대한신경정신의학회 2020 PSYCHIATRY INVESTIGATION Vol.17 No.7

Dysregulated lncRNA and mRNA may promote the progression of ischemic stroke via immune and inflammatory pathways: results from RNA sequencing and bioinformatics analysis

Wang Yingshuang,Feng Feifei,Zheng Pingping,Wang Lijuan,Wang Yanjun,Lv Yaogai,Shen Li,Li Kexin,Feng Tianyu,Chen Yang,Liu Zhigang,Yao Yan 한국유전학회 2022 Genes & Genomics Vol.44 No.1

Background: Long non-coding RNAs (lncRNAs) are widely involved in gene transcription regulation and which act as epigenetic modifiers in many diseases. Objective: To determine whether lncRNAs are involved in ischemic stroke (IS), we analyzed the expression profile of lncRNAs and mRNAs in IS. Methods: RNA sequencing was performed on the blood of three pairs of IS patients and healthy controls. Differential expression analysis was used to identify differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs). Based on the co-expression relationships between lncRNA and mRNA, a series of bioinformatics analysis including GO and KEGG enrichment analysis and PPI analysis, were conducted to predict the function of lncRNA. Results: RNA sequencing produced a total of 5 DElncRNAs and 144 DEmRNAs. Influenza A pathway and Herpes simplex infection pathway were the most significant pathways. EP300 and NFKB1 were the most important target proteins, and Human leucocyte antigen (HLA) family were the key genes in IS. Conclusions: Analysis of this study revealed that dysregulated lncRNAs in IS may lead to IS by affecting the immune and inflammation system.

Adoption instead of purchase

Wang Tianyu 한국콘텐츠학회 2021 ICCC International Digital Design Invitation Exhib Vol.2021 No.12

Stability of Wiener Systems with Dead-zone Using Optimal Position and Velocity Control

Tianyu Wang,Yonghong Tan,Ming Fang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.2

In this paper, a new sufficient condition for the stability of Wiener systems with dead-zone which are also non-smooth nonlinear systems is proposed. In order to analyze the stability, pseudo linearization is implementedto the system. Then, the optimal position and velocity control strategy is derived by minimizing the cost function. Based on the Lyapunov method, the stability condition is obtained. Afterward, simulation examples are presentedto validate the proposed method.

Overlapping coalition formation games for emerging communication networks

Wang, Tianyu,Song, Lingyang,Han, Zhu,Saad, Walid IEEE 2016 IEEE network Vol.30 No.5

<P>Modern cellular networks are witnessing an unprecedented evolution from classical centralized and homogenous architectures into a mix of various technologies, in which the network devices are densely and randomly deployed in a decentralized and heterogenous architecture. This shift in network architecture requires network devices to become more autonomous and, potentially, cooperate with one another. Such cooperation can, for example, take place between interfering small access points that seek to coordinate their radio resource allocation, nearby single-antenna users that can cooperatively perform virtual MIMO communications, or even unlicensed users that wish to cooperatively sense the spectrum of licensed users. Such cooperative mechanisms involve the simultaneous sharing and distribution of resources among a number of overlapping cooperative groups or coalitions. In this article, a novel mathematical framework from cooperative games, dubbed overlapping coalition formation games (OCF games), is introduced to model and solve such cooperative scenarios. First, the concepts of OCF games are presented, and then several algorithmic aspects are studied for two main classes of OCF games. Subsequently, two example applications, interference management and cooperative spectrum sensing, are discussed in detail to show how the proposed models and algorithms can be used in future scenarios of wireless systems. Finally, we conclude by providing an overview on future directions and applications of OCF games.</P>

Adoption instead of purchase

Wang Tianyu 한국콘텐츠학회 2021 한국콘텐츠학회 ICCC 논문집 Vol.2021 No.12

Damping for Wind Turbine Electrically Excited Synchronous Generators

Tianyu, Wang,Guojie, Li,Yu, Zhang,Chen, Fang The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.4

The electrically excited synchronous generator (EESG) is applied in wind turbine systems recently. In an EESG control system, electrical torque is affected by stator flux and rotor current. So the control system is more complicated than that of the permanent-magnet synchronous generator (PMSG). Thus, the higher demanding of the control system is required especially in case of wind turbine mechanical resonance. In this paper, the mechanism of rotor speed resonant phenomenon is introduced from the viewpoint of mechanics firstly, and the characteristics of an effective damping torque are illustrated through system eigenvalues analysis. Considering the variables are tightly coupled, the four-order small signal equation for torque is derived considering stator and rotor control systems with regulators, and the bode plot of the closed loop transfer function is analyzed. According to the four-order mathematical equation, the stator flux, stator current, and electrical torque responses are derived by torque reference step and ramp in MATLAB from a pure mathematical deduction, which is identical with the responses in PSCAD/EMTDC simulation results. At last, the simulation studies are carried out in PSCAD software package to verify the resonant damping control strategy used in the EESG wind turbine system.

Sequence Analysis of cytb Gene in Echinococcus granulosus from Western China

Xiuqin Zhong,Ning Wang,Dandan Hu,Jiahai Wang,Tianyu Liu,Xiaobin Gu,Shuxian Wang,Xuerong Peng,Guangyou Yang 대한기생충학열대의학회 2014 The Korean Journal of Parasitology Vol.52 No.2

Echinococcus granulosus is the causative agent of cystic echinococcosis with medical and veterinary importance in China. Our main objective was to discuss the genotypes and genetic diversity of E. granulosus present in domestic animals and humans in western China. A total of 45 hydatid cyst samples were collected from sheep, humans, and a yak and subjected to an analysis of the sequences of mitochondrial cytochrome b (cytb) gene. The amplified PCR product for all samples was a 1,068 bp band. The phylogenetic analysis showed that all 45 samples were identified as E. granulosus (genotype G1). Ten haplotypes were detected among the samples, with the main haplotype being H1. The haplotype diversity was 0.626, while the nucleotide diversity was 0.001. These results suggested that genetic diversity was low among our samples collected from the west of China based on cytb gene analysis. These findings may provide more information on molecular characteristics of E. granulosus from this Chinese region.

Recent Advancements in Biomaterials for Chimeric Antigen Receptor T Cell Immunotherapy

Gaoyu Yu,Zhichao Ye,Yuyang Yuan,Xiaofeng Wang,Tianyu Li,Yi Wang,Yifan Wang,Jianing Yan 한국생체재료학회 2024 생체재료학회지 Vol.28 No.00

Cellular immunotherapy is an innovative cancer treatment method that utilizes the patient’s own immune system to combat tumor cells effectively. Currently, the mainstream therapeutic approaches include chimeric antigen receptor T cell (CAR-T) therapy, T cell receptor gene-modified T cell therapy and chimeric antigen receptor natural killer-cell therapy with CAR-T therapy mostly advanced. Nonetheless, the conventional manufacturing process of this therapy has shortcomings in each step that call for improvement. Marked efforts have been invested for its enhancement while notable progresses achieved in the realm of biomaterials application. With CAR-T therapy as a prime example, the aim of this review is to comprehensively discuss the various biomaterials used in cell immunotherapy, their roles in regulating immune cells, and their potential for breakthroughs in cancer treatment from gene transduction to efficacy enhancement. This article additionally addressed widely adopted animal models for efficacy evaluating.