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A Method to Reduce Common-mode Voltage of Dual Three-Phase Motor Based on TSPWM
LU Fangke,LU Haifeng,LI Y ongdong,CHAI Jianyun 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
Common-mode voltage is created by variable frequency drives. And it brings problems to the motor drive systems. Six-phase inverter has a total of 64 switching state vectors. And the space vector classification technique is one of the main modulation methods of dual three-phase motor drive systems. In order to reduce the common-mode voltage of the dual three-phase drive system, this paper proposed a new PWM method based on TSPWM. The new method is compared with the traditional space vector classification technique, and the results of simulation and experiments are given to prove the effects.
Haifeng Bian,Guoli Zhang,Qingxi Zhai,Yanyan Du,Yujie Ma,Beibei Yang,Shaochun Tang,Duan Bin,Xiangkang Meng,Hongbin Lu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-
Stainless steel (SS) is a promising material for designing bipolar plates (BPs), but their further applicationis limited by serious corrosion problems in the acidic environment. Ti3C2Tx is expected to be used for SSBPs coatings, while galvanic corrosion will occur after the damage of Ti3C2Tx coating. Herein, a PPY/Ti3C2Tx-AE double-layer coating (DC) is well-designed and prepared on 304SS BP, which is composedof an inner electropolymerized PPY layer and an outer Ti3C2Tx-acrylic epoxy layer. When tested in0.2 M HCl solution, the corrosion potential and corrosion current density of the DC are 38 mV and0.00927 lA cm2 respectively, which are superior to those of the PPY coating and the Ti3C2Tx coating. Moreover, the DC presents the best long-term stability among the three coatings. The excellent corrosionresistance is attributed to the barrier and anodic protection effects as well as the solution of galvanic corrosion. The new coating system provides a new insight into the design of DC coatings of SS BPs.
Temperature Characteristics of Power Ternary Polymer Li-ion Batteries
Fang Haifeng,Cai Lihua,Lu Huaimin,Wei Benjian,Zhu Hongping 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.11
The characteristics of power ternary polymer Li-ion batteries are closely connected to ambient temperature. The capacity characteristic, resistance and state of charge-open circuit voltage (SOC-OCV) curve are important parameters to represent the performance of power batteries and to determine battery management system (BMS) design. The experiments at different ambient temperatures are carried out and the laws between temperature and capacity, resistance and OCV are studied. The capacity drops sharply under low temperature, and increases with a relatively slower rate than under low temperature when the temperature goes up. Polarization and ohmic resistances during charge and discharge process decrease when the temperature rises, and the change rate of ohmic resistance is higher than that of the polarization resistance. Moreover, the change of ohmic resistance under low temperature is more significant than under high temperature. With the decrease of temperature, the SOC-OCV curve moves down, but generally, the curve is affected only slightly by the temperature.
Sheng, Shuang,Lu, Haifeng,Qu, Wenlong,Guo, Ruijie,Yang, Jinlei Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.3
This paper introduces a novel method of on-line identifying the stator resistance and leakage inductance of dual three phase induction motor (DTPIM). According to the machine mathematical model, the stator resistance and leakage inductance can be estimated using the voltage and current values in harmonic subspace. Thus a method of voltage vector injection in harmonic subspace (VVIHS) is proposed, which causes currents in harmonic space. Then the errors between command and actual harmonic currents are utilized to regulate the machine parameters, including stator resistance and leakage inductance. The principle is presented and analyzed in detail. Experimental results prove the feasibility and validity of proposed method.
Zhang Qingzhi,Lu Haifeng,Li Yongdong,Chai Jianyun 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
Free Piston Linear Generator (FPLG) is an ideal power resource in Hybrid Electric Vehicle (HEV) for its potential advantages of low friction loss, variable compression ratio, being suitable for various fuels, high thermal efficiency, etc. No FPLG has been successfully applied to an actual vehicle as lack of reliable control. The first part of this paper consists of introduction to FPLG and its research status. Structure and working principle of FPLG are analyzed in the second part. Then the thermodynamic process is analyzed and mathematical models of all kinds of FPLG using real-time motion control strategy based on location domain are established. After these, verifying work of the six different models established before and the realtime control strategy is carried out. Results show that the mathematical models of FPLG based on location domain work well and the control strategy effects with proper linear generator.
Shear bond strength of zirconia to resin: The effects of specimen preparation and loading procedure
Bingzhuo Chen,Lu Yang,Zhicen Lu,Hongliang Meng,Xinyi Wu,Chen Chen,Haifeng Xie 대한치과보철학회 2019 The Journal of Advanced Prosthodontics Vol.11 No.6
PURPOSE. Shear bond strength (SBS) test is the most commonly used method for evaluating resin bond strength of zirconia, but SBS results vary among different studies even when evaluating the same bonding strategy. The purpose of this study was to promote standardization of the SBS test in evaluating zirconia ceramic bonding and to investigate factors that may affect the SBS value of a zirconia/resin cement/composite resin bonding specimen. MATERIALS AND METHODS. The zirconia/resin cement/composite resin bonding specimens were used to simulate loading with a shear force by the three-dimensional finite element (3D FE) modeling, in which stress distribution under uniform/non-uniform load, and different resin cement thickness and different elastic modulus of resin composite were analyzed. In vitro SBS test was also performed to validate the results of 3D FE analysis. RESULTS. The loading flat width was an important affecting factor. 3D FE analysis also showed that differences in resin cement layer thickness and resin composite would lead to the variations of stress accumulation area. The SBS test result showed that the load for preparing a SBS specimen is negatively correlated with the resin cement thickness and positively correlated with SBS values. CONCLUSION. When preparing a SBS specimen for evaluating bond performance, the load flat width, the load applied during cementation, and the different composite resins used affect the SBS results and therefore should be standardized.
Research on Dynamic Evaluation Method of Slope Stability Based on Monitoring Data
( Xiaopeng Kang ),( Aijun Yao ),( Haifeng Guo ),( Jian Lu ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2
Due to the frequent occurrence of slope instability caused by disasters in recent years, it is particularly important for monitoring the slope disasters and the dynamic evaluation of slope stability. The monitioring data is the most intuitive factor to reflect the stability of the slope. Therefore, it is more urgent to directly evaluate the stability of the slope through the monitoring data of the slope disaster. In this paper, based on BP neural network, the slope s tability dynamic evaluation system-DESlopeStability is developed by MATLAB. Then, the accuracy of the DESlopeStability is verified by the numerical simulation of ABAQUS, which is a three-dimensional finite element software. Finally, this system is applied to the Jietai Temple landslide project in Beijing. Through the above research, the BP neural network can find the nonlinear mapping between the monitoring data and the stability coefficient of the slope based on a large amount of data, and the DESlopeStability system meets the actual engineering requirements and it can be used as an auxiliary means to judge the stability of the slope.
Lejia Sun,Wenmo Hu,Meixi Liu,Yang Chen,Bao Jin,Haifeng Xu,Shunda Du,Yiyao Xu,Haitao Zhao,Xin Lu,Xinting Sang,Shouxian Zhong,Huayu Yang,Yilei Mao 대한암학회 2020 Cancer Research and Treatment Vol.52 No.4
Purpose The systemic inflammation response index (SIRI) has been reported to have prognostic ability in various solid tumors but has not been studied in gallbladder cancer (GBC). We aimed to determine its prognostic value in GBC. Materials and Methods From 2003 to 2017, patients with confirmed GBC were recruited. To determine the SIRI’s optimal cutoff value, a time-dependent receiver operating characteristic curve was applied. Univariate and multivariate Cox analyses were performed for the recognition of significant factors. Then the cohort was randomly divided into the training and the validation set. A nomogram was constructed using the SIRI and other selected indicators in the training set, and compared with the TNM staging system. C-index, calibration plots, and decision curve analysis were performed to assess the nomogram’s clinical utility. Results One hundred twenty-four patients were included. The SIRI’s optimal cutoff value divided patients into high (≥ 0.89) and low SIRI (< 0.89) groups. Kaplan-Meier curves according to SIRI levels were significantly different (p < 0.001). The high SIRI group tended to stay longer in hospital and lost more blood during surgery. SIRI, body mass index, weight loss, carbohydrate antigen 19-9, radical surgery, and TNM stage were combined to generate a nomogram (C-index, 0.821 in the training cohort, 0.828 in the validation cohort) that was significantly superior to the TNM staging system both in the training (C-index, 0.655) and validation cohort (C-index, 0.649). Conclusion The SIRI is an independent predictor of prognosis in GBC. A nomogram based on the SIRI may help physicians to precisely stratify patients and implement individualized treatment.
Shiqi Dai,Chen Chen,Mo Tang,Ying Chen,Lu Yang,Feng He,Bingzhuo Chen,Haifeng Xie 대한치과보철학회 2019 The Journal of Advanced Prosthodontics Vol.11 No.5
PURPOSE. The aim was to study the masking ability of high-translucency monolithic zirconia and provide guidance in selecting resin luting cements in order to mask discolored substrates. MATERIALS AND METHODS. 160 high-translucency zirconia specimens were divided into 32 groups depending on their thickness and shades. Using five shades of try-in paste, the specimens were luted onto the sub strates (Co-Cr, precious-metal, opaque porcelain-sintered Co-Cr, opaque porcelain-sintered precious-metal, and 5M3-shade zirconia). All CIELAB color parameters were measured and statistically analyzed. RESULTS. Zirconia shade and thickness and try-in paste shade affected CIELAB color parameters (P=.000) in different substrates groups, and there were interactions among these factors (P=.000). All five try-in paste shades can be chosen to achieve ΔE values of zirconia with 1.2 - 1.5 mm for masking dark-tooth-like 5M3-shade and zirconia with 1.5 mm for masking precious-metal groups < 2.6. Only suitable try-in paste shades were used, can ΔE values that less than 2.6 be achieved when applied translucent monolithic zirconia with 0.7-1.0 mm for masking dark-tooth-like 5M3-shade and zirconia with 0.7 - 1.2 mm for masking precious-metal groups. CONCLUSION. Choosing suitable resin cement shades is necessary for high-translucency monolithic zirconia to achieve ideal masking ability (ΔE < 2.6) on the dark-tooth.