A Novel Method for Estimating State-of-Charge in Power Batteries for Electric Vehicles

Nan Zhang,Yunshan Zhou,Qiang Tian,Xiaoying Liao,Feitie Zhang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.5

Estimation of the state-of- charge (SOC) of power batteries has always been the focus of electric vehicle users’ criticism. Accurate SOC is beneficial for extending the mileage of electric vehicles and the life of the battery pack. The key to improving SOC accuracy is to establish its accurate model and combine it with an appropriate estimation algorithm. Based on characterization experiments related to SOC, this paper describes a second-order charge–discharge resistor–capacitor model that can accurately simulate external characteristics of the battery and identify them online. An improved adaptive unscented Kalman filter algorithm based on Sage–Husa is introduced to estimate SOC. The reliability of the algorithm is verified by building a MATLAB/Simulink simulation model. The results show that the improved algorithm displays increased robustness and can quickly converge to the true value; the steady-state error is also within a small range.

The precipitation of three Ca-P phase whiskers from an acid solution through hydrolysis of urea

Yunqing Kang,Yunshan Liu,Zhongbing Huang,Yadong Yao,Xiaoming Liao,Li Liao,Guangfu Yin 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.2

Hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and dicalcium phosphate (DCP) whiskers with high aspect ratio and good crystallinity were successfully prepared by hydrolysis of urea in acid solutions at 90oC for 96 h. The precipitated whiskers were characterized by XRD, SEM and TEM. The lengths and aspect ratios of whiskers could be controlled by the precipitation agent, urea, with a proper incubation time. Results revealed good morphology and crystallinity of the precipitated whiskers without any impurities. TEM indicated single crystal diffraction patterns of HA and β-TCP were clearly identified. The high aspect ratio of whiskers could be potentially used as the scaffold in tissue engineering or filler in composite biomaterials to enhance mechanical properties. Hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP) and dicalcium phosphate (DCP) whiskers with high aspect ratio and good crystallinity were successfully prepared by hydrolysis of urea in acid solutions at 90oC for 96 h. The precipitated whiskers were characterized by XRD, SEM and TEM. The lengths and aspect ratios of whiskers could be controlled by the precipitation agent, urea, with a proper incubation time. Results revealed good morphology and crystallinity of the precipitated whiskers without any impurities. TEM indicated single crystal diffraction patterns of HA and β-TCP were clearly identified. The high aspect ratio of whiskers could be potentially used as the scaffold in tissue engineering or filler in composite biomaterials to enhance mechanical properties.

Multiple Peer-To-Peer Relay Network Robust Beamforming Based on Lorentz-Positive Matrices

Jianhua Li,Yunshan Hou 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.10

Aiming at minimizing the total transmit power of relay nodes in the multiple peer-to-peer relay network in the presence of channel estimation error, a relay beamforming method based on Lorentz positive matrix is proposed. Firstly, assuming the channel state information of the second hop in the relay network is uncertain and the signal to noise ratios of the destination nodes are given, the expression of total relay nodes transmit power minimization optimization problem is deduced. Secondly, some real valued variables are defined and the concept of Lorentz cone is used to transform the optimization problem into a real valued problem. Finally, using the equivalent linear matrix inequality description of Lorentz positive matrices, the relay transmit power minimization problem is transformed into a real valued convex optimization problem. The proposed method overcomes the problem existing in the conventional robust relay beamforming methods based on semi definite relaxation technique, which sometimes yield solution matrix of with a rank greater than 1. Simulation results show that in the case of different relay nodes and channel error coefficients, the proposed method yields minimum relay transmit power in line with the results of the robust relay beamforming method based on semi definite relaxation technique, which validates the effectiveness of the proposed method.

Acoustic emission localization in concrete using a wireless air-coupled monitoring system

Yuanxue Liu,Yunshan Bai,Guangjian Gao,Shuang Su 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.32 No.4

The contact acoustic emission (AE) monitoring system is time-consuming and costly for monitoring concrete structures in large scope, in addition, the great difference in acoustic impedance between air and concrete makes the detection process inconvenient. In this work, we broaden the conventional AE source localization method for concrete to the non-contact (air-coupled) micro-electromechanical system (MEMS) microphones array, which collects the energy-rich leaky Rayleigh waves, instead of the relatively weak P-wave. Finite element method was used for the numerical simulations, it is shown that the propagation velocity of leaky Rayleigh waves traveling along the air-concrete interface agrees with the corresponding theoretical properties of Lamb wave modes in an infinite concrete slab. This structures the basis for implementing a non-contact AE source location approach. Based on the experience gained from numerical studies, experimental studies on the proposed air-coupled AE source location in concrete slabs are carried out. Finally, it is shown that the locating map of AE source can be determined using the proposed system, and the accuracy is sufficient for most field monitoring applications on large plate-like concrete structures, such as tunnel lining and bridge deck.

Comparison of Deformation Behavior of Saturated Sand under Constant and Variable Deviatoric Stress

Zhiyi Zhao,Gang Deng,Yunshan Han,Zhaopeng Zhang,Yanli Dong,Ying Gao 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.3

The cyclic triaxial tests were carried out on Fujian standard sand under two stress paths, the constant deviatoric stress path (CDS) and constant stress-ratio path (variable deviatoric stress, VDS), and the influence of cyclic deviatoric stress on the development characteristics of saturated sand was preliminarily discussed. Under the condition of the same consolidation stress state and amplitude of cyclic spherical stress, the amplitude of deviatoric stress under the two stress paths was different. The test results indicated that cyclic deviatoric stress had significant effect on the volumetric and shear strain in soil. When the consolidation deviatoric stress was relatively small, the volumetric and shear strain curves under these two stress paths almost coincided. However, the cyclic deviatoric stress had a stronger effect with an increase in the consolidation deviatoric stress. During the loading and unloading stages, the slope of the volumetric strain curve under the VDS path was smaller than that under the CDS path. The accumulated volumetric strain under the VDS path was greater than that under the CDS path. In the loading stage, the growth rate of shear strain under the VDS path was greater than that under the CDS path, but the opposite relationship was observed in the unloading stage. The presence of cyclic deviatoric stress accelerated or slowed down the accumulation of shear strain. These phenomena were related to the positional relationship between the stress state of soil and the critical state line.

Research on Ant Colony Algorithm Optimization Neural Network Weights Blind Equalization Algorithm

Yanxiang Geng,Liyi Zhang,Yunshan Sun,Yao Zhang,Nan Yang,Jiawei Wu 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.2

The project of ant colony algorithm optimization neural network combining blind equalization algorithm is proposed. The better initial weights of neural networks are provided because of the randomness, ergodicity and positive feedback of the ant colony algorithm. And then, a combination of optimal weights are found through BP algorithm, which is fast local search speed. Thus blind equalization performance is improved. Computer simulation show that, the novel blind equalization algorithm speeds up the convergence rate, reduces the remaining steady-state error and bit error rate, which is compared with the Neural Network Blind Equalization Algorithm(NNBE) and Genetic Algorithm optimization Neural Network Blind Equalization Algorithm(GA-NNBE) .

Combined effects of yaw and tilt angles of separated overfire air on the combustion characteristics in a 1,000 MW coal-fired boiler: A numerical study

Wei Jin,Chamin Geng,Ya’ou Wang,Huan Ma,Yunshan Dong,Fengqi Si 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.4

Separated overfire air (SOFA) is typically employed in coal-fired boilers with air staged technology to sustain lower NOX emission, and SOFA nozzle angles are crucial adjustment parameters. In this work, the combined effects of SOFA yaw and tilt angles on combustion characteristics were numerically investigated for a 1,000MW dual circle tangentially coal-fired boiler. Numerical results show that the forward increase of the SOFA yaw angle from 0o brings about the enlarged SOFA tangential circle and the gradual appearance of bimodal high-temperature zones at furnace exit. With further tuning SOFA tilt angles vertically, the bimodal high-temperature zones would separate to the two halves of the furnace, inducing a more severe deviation of gas temperature. Besides, the gas residual rotating momentum is strengthened as SOFA yaw angles forward increase, resulting in the enhancement of traction effect in the upper furnace as well as the rise of flame. However, the gas velocity deviation is somewhat eliminated as SOFA rotates reversely. No matter that the SOFA yaw angle increases forward or reversely, the coal burnout would deteriorate with the overly enlarged SOFA tangential circles. Tuning SOFA yaw and tilt angles, respectively, at 5o and 0o can simultaneously guarantee lower CO and NOX emissions.