Analysis and Optimization of Asymmetric Hybrid Permanent Magnet Motor for Electric Vehicle

Liu Kaiwen,Shi Liwei,Liu Zhengwei,Wang Wenqiang,Ding Hongshan 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5

An asymmetric hybrid permanent magnet motor (AHPMM) is proposed for the traditional permanent magnet motor (TPMM) with a large amount of rare earth materials and high cogging torque. The equivalent magnetic circuit model of the motor is established and the factors affecting the fluctuation of cogging torque are analyzed. With the objective of reducing the torque ripple and cogging torque of the AHPMM, the motor is parametrically modeled and analyzed, and multi-objective hierarchical optimization of the motor parameters is carried out using a hybrid algorithm combining the response surface algorithm and the single scan method, which ultimately determines the optimal combination of motor dimensional parameters. The electromagnetic performance of the AHPMM compared to the TPMM is analyzed using the finite element method. The results show that, without any decrease in output torque, the use of rare-earth materials is reduced by 18.5%, the cogging torque and the total harmonic distortion of the No-load back EMF waveform are reduced by 0.78 Nm and 4.7% respectively compared to the TPMM. Finally, a prototype motor is manufactured and the validity of the theoretical analysis and design of the AHPMM is verified through experiments.

Dynamic response of railway vehicles under unsteady aerodynamic forces caused by local landforms

Zhengwei Chen,Tanghong Liu,Ming Li,Miao Yu,Zhaijun Lu,Dongrun Liu 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.3

When a railway vehicle runs in crosswinds, the unsteady aerodynamic forces acting on the train induced by the vehicle speed, crosswind velocity and local landforms are a common problem. To investigate the dynamic performance of a railway vehicle due to the influence of unsteady aerodynamic forces caused by local landforms, a vehicle aerodynamic model and vehicle dynamic model were established. Then, a wind-loaded vehicle system model was presented and validated. Based on the wind-loaded vehicle system model, the dynamic response performance of the vehicle, including safety indexes and vibration characteristics, was examined in detail. Finally, the effects of the crosswind velocity and vehicle speed on the dynamic response performance of the vehicle system were analyzed and compared.

Genome-wide analysis of the Dof transcription factors in castor bean (Ricinus communis L.)

Zhengwei Jin,Aizhong Liu,Umashankar Chandrasekaran 한국유전학회 2014 Genes & Genomics Vol.36 No.4

DNA binding with one finger (Dof) transcriptionfactors are unique in plants, characteristically composedof a Dof domain in structure, functionally involvedin mediating many processes of plant growth and development. In this study, we report a genome-wide analysisfor Dof gene family in castor bean (Ricinus communis L.,Euphorbiaceae) genome. In total, 21 RcDof genes wereidentified and their constructional characterization, classesand phylogenetic relationships were documented. Theexpression profiles of the 21 RcDof genes among differenttissues were inspected using the high throughput RNA-Seqdata. Finally, SqRT-PCR analysis was performed to test thetranscriptional responses of the 21 RcDof genes to abscisicacid (ABA) and/or gibberellic acid (GA) signals, resultingin the identification of 18 RcDof genes responsive to ABAand/or GA signals. Thus, this study would provide basicinformation in understanding the molecular basis of theRcDof family and their potential function in regulating thegrowth and development of castor bean.

Hyper-heuristic algorithm for traffic flow-based vehicle routing problem with simultaneous delivery and pickup

Wang Zhengwei,Liu Jinlong,Zhang Jingling 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.6

To address the realistic problem of seriously reducing distribution efficiency and increasing distribution cost caused by road traffic congestion, this paper constructs a time-dependent speed describing vehicle travel speed and road traffic flow by simulating the change of urban traffic flow, to establish a vehicle route problem model considering traffic flow with distribution cost and customer satisfaction as optimization objectives. To solve this problem, a hyper-heuristic algorithm based on tabu search is designed in this paper, in which the underlying search operator is selected more efficiently by a high-level heuristic strategy. In addition, the correctness of the model and the effectiveness of the algorithm are verified by conducting simulation experiments on several benchmark sets. Experiment results are shown as the travel speed of the vehicle increases, the average customer satisfaction in lc1-type instances increases to 0.94. And the impact of urban traffic changes on logistics costs and customer satisfaction is further analyzed.

Comparison study of the effect of bridge-tunnel transition on train aerodynamic performance with or without crosswind

Lei Zhou,Tanghong Liu,Zhengwei Chen,Wenhui Li,Zijian Guo,Xuhui He,You-Wu Wang 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.32 No.6

This paper studied the case of high-speed train running from flat ground to bridges and into/out of tunnels, with or without crosswind based on the Computational Fluid Dynamics (CFD) method. First, the flow structure was analyzed to explain the influence mechanisms of different infrastructures on the aerodynamic characteristics of the train. Then, the evolution of aerodynamic forces of the train during the entire process was analyzed and compared. Additionally, the pressure variation on the train body and the tunnel wall was examined in detail. The results showed that the pressure coefficient and the flow structure on both sides of the high-speed train were symmetrical for no crosswind case. By contrast, under crosswind, there was a tremendous and immediate change in the pressure mapping and flow structure when the train passing through the bridge-tunnel section. The influence of the ground-bridge transition on the aerodynamic forces was much smaller than that of the bridge-tunnel section. Moreover, the variation of aerodynamic load during the process of entering and exiting the bridge-tunnel sections was both significant. In addition, in the case without crosswind, the change in the pressure change in the tunnel conformed to the law of pressure wave propagation, while under crosswind, the variation in pressure was comprehensively affected by both the train and crosswind in the tunnel.

Yaw effects on train aerodynamics on a double-track viaduct: A wind tunnel study

Wenhui Li,Tanghong Liu,Pedro Martinez-Vazquez,Zhengwei Chen,Xiaoshuai Huo,Zijian Guo,Yutao Xia 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.33 No.3

The aerodynamic performance of a scaled high-speed train model mounted on a double-track viaduct was studied through a wind tunnel test. The pressure distribution of different loops and the centerline on the streamlined nose region, as well as the aerodynamic load coefficients of the leading car were explored under yaw effects ranging from β=-30° to β=30°. Results showed that Reynolds effects became independent when the wind speed surpassed 40 m/s, the corresponding Re of which equals 6.51 × 105 . The pressures recorded along the centerline of train nose for the upstream scenario, was more sensitive to the yaw effects as the largest pressure difference gradually broadened against yaw angles. In addition, the pressure coefficients along the centerline and symmetrical taps of the loops, approximately fit a quadratic relationship with respect to yaw angles. The presence of the tracks and viaduct decks somehow mitigated the intensity of the airflow at downstream side. The experimental test also revealed that, the upstream configuration provided higher mean side force, yawing, and rolling moments up to β=20° whereas over that angle the force and moments exhibited the opposite performance.

An automated longquan celadon glaze thickness measurement method based on optical coherence tomography

Yang Zhou,Longjie Shi,Gang Ceng,Tiebing Liu,Yang Shi,Zhengwei Chen,Fenglin Wang,Yuefeng Ceng 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.3

The thickness of glaze is one of the important indicators in the quality evaluation of Longquan celadon. But till now, there isno automatic and non-destructive method to measure it. In order to satisfy this demand, an automated method has beenproposed to measure the glaze thickness based on optical coherence tomography (OCT) technique. According to themorphological characteristics of celadon glaze in OCT image, the proposed method locates the upper and lower boundariesof the glaze layer, then the glaze thickness is automatically calculated after the axial resolution calibration of the OCT imagesfor different categories of Longquan celadon. In the experiment, the glaze OCT images of 6 different categories of Longquanceladon were applied in the glaze thickness estimation. By comparing with the physical measuring result, this method is provedto be able to measure the glaze thickness rapidly and non-destructively and the performance is enough to meet the demandof the industrial application.

Nondestructive Early Detection of Bruising in Pear Fruit Using Optical Coherence Tomography

Yang Zhou,Jianwei Mao,Di Wu,Tiebing Liu,Yun Zhao,Wujie Zhou,Zhengwei Chen,Fangni Chen 한국원예학회 2019 원예과학기술지 Vol.37 No.1

Pear fruit is susceptible to mechanical injury during harvesting, packaging, and transportation. Optical coherence tomography (OCT) can provide information concerning chemical and microstructural changes of fruit tissues. Therefore, using OCT to evaluate fruit quality is of great significance. In this study, OCT was used for early detection of subtle bruise symptoms underneath the pear peel. First, the signal intensity versus depth in relation to the OCT images of fruit tissue was determined, which was derived from the values of the OCT signal slope (OCTSS) and 1/e light penetration depth (D1/e). Furthermore, shaping (α) and scaling (β) indices were estimated by fitting a gamma distribution function to the signal intensity profile. After mechanical injury, OCTSS, α, and β decreased and the D1/e value increased. Distribution analysis of the relationship between α versus β served as an effective method to identify tissue bruising at an early stage. In conclusion, the results suggest that OCTSS, D1/e, and the α versus β distribution are closely correlated with bruise injury in pear fruit tissues. Thus, OCT is a promising technology for early and nondestructive bruise detection.

Study of a New Imaging Strategy Based on Compressed Sensing to Shorten the Imaging Time of a Fourier Telescope

Lei Dong,Zhenwu Lu,Xinyue Liu,Zhengwei Li,Liang Wang 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.12

A Fourier telescope (FT) is an imaging system based on laser illumination and optical aperture synthesis and is suitable for imaging distant targets with high resolution through the atmosphere. The imaging time of a conventional FT is so long (about two hours) as to limit its practical applications. In order to shorten the imaging time of a Fourier telescope, we propose a new imaging system called the compressed sensing Fourier telescope (CS-FT). The image quality, the imaging time and the effects of noise of the new system are studied in detail. Based on the analysis, we find that by reasonably choosing the total sampling rate (TSR), the imaging time of the CS-FT is obviously shorter than that of the conventional FT while the image quality of the CS-FT is near that of the conventional FT. Worth noting is that with the smaller values of the low-frequency sampling rate (LSR) and the order of the sampling probability density function (OPDF), the CS-FT can achieve a better image quality. The reconstruction results of the field data show that the CS-FT can reduce the imaging time of a FT in an actual noise environment.

Microstructural Effect on Cold Strengthening Mechanism of MP159 Alloys

Luorong Dengzhu,Leiming Fang,Bin Gan,Zhengwei Xiong,Qian Liu,Yi Liu,Jia Yang,Jun Li,Zhipeng Gao 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.2

Previous investigations on MP159 alloys have largely reported the striking reinforcement performance after cold deformation,which the deformation mechanism was attributed to HCP phases and deformed twins and so on. To data, the microstructuraleffect on cold strengthening mechanism of MP159 alloy was still controversial. In this work, the processes of microstructuralevolution were elaborated through multi-scale structural characterizations. In the initial MP159, the recrystallized grainsand Σ3 twins (<111> 60°) play a dominant role in the microstructures. After cold drawing, the microcosmic dislocationswere significantly increased in the deformed grains. The mesoscopic Σ3 twins were seriously deformed to become thedeformed twins, inducing that the grains were refined. Meanwhile, the grain boundaries were broken and the HAGBs weresubsequently transformed to the LAGBs. The microstructural transition of dislocations → LAGBs ← HAGBs was confirmed. The high stacking fault energy in the deformed twins promoted a high strain energy stored in the MP159, forming the macroscopical<111> //RD texture. The series of microstructural changes induced the significant enhancement of the strengthand hardness. The microstructural effect on cold strengthening mechanism of MP159 alloys was clarified, which would bea great significance to strengthening metallic materials in the current investigations.