http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Improved Circuit Model for Simulating IGBT Switching Transients in VSCs
Haleem, Naushath Mohamed,Rajapakse, Athula D.,Gole, Aniruddha M. The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6
This study presents a circuit model for simulating the switching transients of insulated-gate bipolar transistors (IGBTs) with inductive load switching. The modeling approach used in this study considers the behavior of IGBTs and freewheeling diodes during the transient process and ignores the complex semiconductor physics-based relationships and parameters. The proposed circuit model can accurately simulate the switching behavior due to the detailed consideration of device-circuit interactions and the nonlinear nature of model parameters, such as internal capacitances. The developed model is incorporated in an IGBT loss calculation module of an electromagnetic transient simulation program to enable the estimation of switching losses in voltage source converters embedded in large power systems.
Multicriteria-Based Location Privacy Preservation in Vehicular Ad Hoc Networks
Farman, Haleem,Jan, Bilal,Talha, Muhammad,Zar, Abi,Javed, Huma,Khan, Murad,Din, Aziz Ud,Han, Kijun Hindawi Limited 2018 Complexity Vol.2018 No.-
<P>Vehicular ad hoc networks (VANETs) are the preferable choice for Intelligent Transportation Systems (ITS) because of its prevailing significance in both safety and nonsafety applications. Information dissemination in a multihop fashion along with privacy preservation of source node is a serious but challenging issue. We have used the idea of the phantom node as the next forwarder for data dissemination. The phantom node (vehicle) hides the identity of actual source node thus preserving the location privacy. The selection of the phantom node among the set of alternatives’ candidate vehicles is considered as a multicriteria-based problem. The phantom node selection problem is solved by using an analytical network process (ANP) by considering different traffic scenarios. The selection is based on different parameters which are distance, speed, trust, acceleration, and direction. The best alternative (target phantom vehicle) is selected through an ANP where all the alternatives are ranked from best to worst. The vehicle having maximum weight is considered to be the best choice as a phantom node. In order to check the stability of the alternatives’ ranking, sensitivity analysis is performed by taking into account different traffic scenarios and interest level of candidate vehicles.</P>
Abdul Haleem,Sidra Bibi Syaal,Muhammad Ajmal,Jaweria Ambreen,Sajid Rauf,Nasir Ali,Saz Muhammad,Afzal Shah,Muhammad Abid Zia,Muhammad Siddiq 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.4
Here in, we demonstrate facile fabrication of silver and palladium nanoparticles in dual responsive poly(Nisopropylacrylamide- co-2-Acrylamido-2-methylpropane sulfonic acid) microgel with temperature- and pH-dependent catalytic potential. Palladium-based catalyst showed better catalytic efficiency as compared to silver-based catalyst for degradation of Rhodamine-B and P-Nitrophenol in aqueous medium under the same set of reaction conditions. The responsive nature of the microgel was found to be useful to tune the catalytic activity of the as-prepared catalysts, and reduction rate was enhanced with the pH and temperature elevation of the reaction medium; however, the increasing trend was slowed in the volume phase transition region of the microgel. Under a specific set of reaction conditions, the reduction of Rhodamine-B was as fast as 0.968 and 0.571 min1 when catalyzed with palladium and silver based catalysts, respectively. The hydrodynamic radius of the particles of microgel support was found to be in the range of 65- 180 nm when pH and temperature of the medium were varied in the range of 2-12 and 25-45, respectively. The estimated diameter of silver and palladium nanoparticles fabricated in the microgel support under the same set of reaction conditions was 9-15 and 7-11 nm, respectively.
Improved Circuit Model for Simulating IGBT Switching Transients in VSCs
Naushath Mohamed Haleem,Athula D. Rajapakse,Aniruddha M. Gole 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6
This study presents a circuit model for simulating the switching transients of insulated-gate bipolar transistors (IGBTs) with inductive load switching. The modeling approach used in this study considers the behavior of IGBTs and freewheeling diodes during the transient process and ignores the complex semiconductor physics-based relationships and parameters. The proposed circuit model can accurately simulate the switching behavior due to the detailed consideration of device–circuit interactions and the nonlinear nature of model parameters, such as internal capacitances. The developed model is incorporated in an IGBT loss calculation module of an electromagnetic transient simulation program to enable the estimation of switching losses in voltage source converters embedded in large power systems.
Shah Sayyed Haleem,Wang Xiaoyuan,Abubakar Usman,Gao Peng 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.5
Permanent magnet synchronous machines, especially interior permanent magnet (IPM) synchronous machines, are being used widely nowadays in a variety of applications. The (IPM) synchronous machine vibration and noise remain one of the critical factors to consider when some new design prototype of the machine is taken into consideration. In this paper, an effi cient modular type fractional slot concentrated winding (FSCW) interior type permanent magnet synchronous motor (IPMSM) is designed, taking into account the capability of fault tolerance and open circuit fault conditions. The radial force and the associated vibration phenomenon are fi rst investigated for the modular type (IPMSM) under normal operating conditions and then under symmetrical and asymmetrical three-phase units open circuit fault conditions. Two-dimensional (2-D) Fourier Transform has been used to investigate the relationship between the faulty operating conditions and the associated induced harmonics in the radial force density of the machine. Then, a detailed harmonic structural analysis, along with a three-dimensional (3-D) transient structural analysis, is performed on the stator of the proposed machine to investigate and verify the normal healthy design approach and the machine fault operating cases under post-fault conditions. Lastly, the vibration and noise characteristics of the prototype machine under the symmetrical and asymmetrical three-phase units’ faulty conditions are thoroughly investigated for comparison purposes over a wide operating speed range. The fi ndings from this comparative analysis are validated through experiments, which confi rm the validation of the proposed design. Moreover, the associated considerations can be used by machine designers to lower the vibration and noise level in fault-tolerant modular design machines.
Redispersible Freeze-dried Quercetin-loaded Liposomal Formulations Stabilized with Lyoprotectants
윤지애,Iqra Haleem,김형민,윤새미,박기환,이재휘 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.6
Enhanced physical stability of quercetin-loaded liposomes redispersed in water after freeze-drying through four different saccharides used as lyoprotectants.