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Ben, Tong,Wang, Jin,Chen, Long,Jing, Libing,Yan, Rongge The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.11
The amorphous alloy used in a switched reluctance motor core can greatly improve the efficiency of the motor. However, its large magnetostrictive coefficient and strong stress sensitivity (i.e., inverse-magnetostriction effect) increase the core vibration and limit the precise control capability of the electrical signals. A vibration reduction method based on the inverse-magnetostriction effect is proposed to control the electromagnetic vibration of a switched reluctance motor with amorphous alloy cores (SRMA). First, a nonlinear magnetostriction and inverse-magnetostriction effect model (NMIE model) of an amorphous alloy and the compressive stress applied structure for the stator teeth are proposed. Then, considering the influence of static compressive stress and dynamic electromagnetic stress on the magnetic properties of the core material, a two-way dynamic electromagnetic force coupling model of the SRMA is constructed and solved. Finally, the vibration characteristics of the SRMA core are calculated. The obtained results show that the radial electromagnetic stress of the improved structure is reduced by 33.6%, which verifies the feasibility of the proposed vibration reduction method.
Torque ripple reduction for switched reluctance motors using global optimization algorithm
Ben, Tong,Nie, Heng,Chen, Long,Jing, Libing,Yan, Rongge The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.11
Global optimization algorithms are widely used to effectively suppress the torque ripple in switched reluctance motors (SRMs). In this paper, an improved velocity-controllable particle swarm optimization algorithm (VCPSO) is proposed to optimize the turn-of angle of an SRM under the current chopping control (CCC) method. In addition, the performances of three global optimization algorithms are compared and analyzed. The specific steps are outlined as follows. First, the static non-linear inductance-current-position and torque-current-position curves of the SRM are obtained through finite-element calculations, and a non-linear model of the SRM is established on this basis. Second, the turn-of angle optimization method based on the VCPSO is proposed. Finally, the performances of the simulated annealing algorithm (SA), the genetic algorithm (GA), and the proposed algorithm are compared and analyzed in terms of torque ripple suppression. The obtained results show that the proposed VCPSO has the advantages of a low number of iterations, low torque ripple, and small peak current in the torque ripple reduction issue of the SRM.
Tekaya, Seifeddine Ben,Tipayno, Sherlyn,Chandrasekaran, Murugesan,Yim, Woo-Jong,Sa, Tong-Min Korean Society of Soil Science and Fertilizer 2012 한국토양비료학회지 Vol.45 No.4
Heavy metals and metalloids removal can be considered as one of the most important world challenges because of their toxicity and direct impact on human health. Many processes have been introduced but biological processes of remediation seem to offer the most suitable solution in terms of efficiency and low cost. Actinobacteria constitute one of the major microbial populations in soil, and this can be attributed to their adaptive morphological structure as well as their exceptional metabolic power. Among microbes, actinobacteria are morphologic intermediate between fungi and bacteria. Studies on microbial diversities in metal contaminated lands have shown that actinobacteria may constitute a dominantly active microbiota in addition to ${\alpha}$ Proteobacteria. Furthermore, isolation studies have shown metal removal mechanisms which are reminiscent of notable multiresistant strains, such as Cupriavidus metallidurans. Apart from members of genus Streptomyces, which produce more than 90% of commercialized antibiotics, and the nitrogen fixing Frankia, little attention has been given to other members of this phylum. This is because of difficult culture condition requirements and maintenance. In this review, we focused on specific isolation of actinobacteria and their potential applications in metal bioremediation and plant growth promotion.
Metadynamic and Static Recrystallization Softening Behavior of a Bainite Steel
Lixin Li,Liangyu Zheng,Ben Ye,Zeqiong Tong 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.1
The metadynamic recrystallization (MDRX) and static recrystallization (SRX) softening behavior of a bainitesteel was investigated by two-pass isothermal compression experiments at temperatures of 1173, 1273, 1373, and1473 K and strain rates of 0.01, 0.1, 1, and 10 s-1with inter-pass times of 1, 5, 10, and 30 s on a Gleeble-1500thermo-mechanical simulator. Kinetic equations were developed to evaluate the softening fractions caused byMDRX and SRX. A comparison between the experimental and predicted softening fractions showed that the proposedkinetic equations can provide a precise estimation of the MDRX and SRX behavior of the studied steel. Theresults based on the kinetic equations indicated that the MDRX and SRX softening fraction increases with theincrease in strain rate, deformation temperature, inter-pass time, and pre-strain; the activation energy of MDRX ismuch smaller than that of SRX; and the no-recrystallization temperature of the investigated steel is 1179.4 K.
Chen Long,Zhang Chunwei,Ben Tong,Nie Heng 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2
As the power transfer efficiency (PTE) is rapidly reduced due to the high offset between the transmitter and the receiver in the wireless power transfer (WPT) system, a Bidirectional Staggered Solenoid Structure (BSSS) with high anti-offset performance was proposed in this paper. Firstly, the factors that affect the PTE are analyzed by establishing a mathematical model of the magnetic coupling structure. Secondly, a parameter optimization method for the traditional flat solenoid coil (FSC) is proposed, which reduces the volume of the magnetic core without reducing the anti-offset ability. Then, the anti-offset performance of the optimized magnetic coupling structure is analyzed and compared with the square, the circle, and the DD (double D) coils structure by three-dimensional (3-D) finite element analysis (FEA). Finally, the anti-offset performance of the structure is verified by a S/S compensated WPT prototype. The PTE is still high when the power transfer distance (PTD) is 164 mm. When the offset distance in X and Y directions increases from 0 to 150 mm, PTE only decreases by 2.62% and 3.71%, respectively.
Li-Bing Jing,Jia Cheng,Tong Ben 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.4
This paper presents a new analytical method for the computation of magnetic fi eld distributions and electromagnetic performances in switched reluctance machines (SRM). The proposed model is suffi ciently general to be used with any number of stator slots and rotor poles with electrically excited. Due to the inherent nonlinear characteristics of SRM, the conventional analytic model has a limited accuracy which does not take into account the saturation. In order to calculate the accuracy and consider the local magnetic saturation on the stator and rotor teeth, the proposed method is based on the resolution of 2-D Laplace’s and Poisson’s equations in polar coordinates by the separation of variables technique. The solution region is divided into three types of regular subdomains, viz. air gap, stator slots and rotor slots. Magnetic fi eld distributions, fl ux linkage, self-inductance, mutual inductance and static electromagnetic torque computed with the proposed analytical method are validated through fi nite-element method.
Calculation of Torque and Loss of Coaxial Magnetic Gear with Halbach Array in 3D Model
Jing Libing,Liu Wei,Tang Weizhao,Rao Yingying,Tan Can,Ben Tong 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.3
In two-dimensional fi eld, the end eff ect exists in the calculation of the electromagnetic characteristics of the magnetic gear, which leads to the inaccurate calculation of the air-gap magnetic fi eld and torque. In order to improve the calculation accuracy of the electromagnetic characteristics of the magnetic gear, a 3D coaxial magnetic gear (CMG) with Halbach arrays distribution is proposed in this paper. Using the unilateral eff ect of the Halbach arrays, the magnetic fi eld on the air gap side is strengthened, and the magnetic fi eld on the iron yoke side is weakened. The topology of CMG with 4 inner and 17 outer poles is established and compared with the 2D model with the same parameters. The results show that the 3D CMG with Halbach array distribution can eff ectively reduce the torque ripple, and the accuracy of torque and loss calculation is improved compared with 2D model. The analysis results can provide a basis for the design and manufacture of magnetic gear.
Predicted temperature-increase-induced global health burden and its regional variability
Lee, Jae Young,Kim, Ho,Gasparrini, Antonio,Armstrong, Ben,Bell, Michelle L.,Sera, Francesco,Lavigne, Eric,Abrutzky, Rosana,Tong, Shilu,Coelho, Micheline de Sousa Zanotti Stagliorio,Saldiva, Paulo Hila Elsevier 2019 Environment international Vol.131 No.-
<P><B>Abstract</B></P> <P>An increase in the global health burden of temperature was projected for 459 locations in 28 countries worldwide under four representative concentration pathway scenarios until 2099. We determined that the amount of temperature increase for each 100 ppm increase in global CO<SUB>2</SUB> concentrations is nearly constant, regardless of climate scenarios. The overall average temperature increase during 2010–2099 is largest in Canada (1.16 °C/100 ppm) and Finland (1.14 °C/100 ppm), while it is smallest in Ireland (0.62 °C/100 ppm) and Argentina (0.63 °C/100 ppm). In addition, for each 1 °C temperature increase, the amount of excess mortality is increased largely in tropical countries such as Vietnam (10.34%p/°C) and the Philippines (8.18%p/°C), while it is decreased in Ireland (−0.92%p/°C) and Australia (−0.32%p/°C). To understand the regional variability in temperature increase and mortality, we performed a regression-based modeling. We observed that the projected temperature increase is highly correlated with daily temperature range at the location and vulnerability to temperature increase is affected by health expenditure, and proportions of obese and elderly population.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Future health burden with respect to CO<SUB>2</SUB> increase was projected in 28 countries. </LI> <LI> Future temperature and mortality were compared across locations. </LI> <LI> Daily temperature range determines the rate of temperature increase. </LI> <LI> Amount of health expenditure determines the vulnerability to temperature change. </LI> </UL> </P>