Syahrun Nizam Md Arshad @ Hashim
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Syahrun Nizam Md Arshad @ Hashim
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Syahrun Nizam, Md Arshad @ Hashim
Alternative Name
Arshad, S. N.M.
Arshad, Syahrun Nizam Bin M.
Nizam Md Arshad, Syahrun
Md Arshad, Syahrun Nizam
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Scopus Author ID
56177750400

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Study of soil resistivity using wenner four pin method: Case study

2020-12-07 , Sazali M.S. , Wooi Chin Leong , Wong T.S. , Syahrun Nizam Md Arshad @ Hashim , Abdul-Malek Z. , Nabipour-Afrouzi H.

Soil resistivity is usually measured at the selected site either for new installation or in the existing grounding system. In this paper, soil resistivity test has been done to study the soil resistivity around the 33 kV substation according to IEEE 81-1983 standard. A factory site located in Kulim Hi-tech, Malaysia has been selected to research on the soil resistivity. The soil resistance measured in this study is then be calculated in using the soil resistivity formula. The soil resistivity shows that the longer the distance between rods, the lower the resistivity of soil due to larger soil volume. The lowest soil resistivity around the substation is 3.454 Ω.m, which is on the left side of the substation with a distance of 5 meters between the rods followed by front side with 15.71 Ω.m, right side with 34.243 Ω.m and backside with 45.239 Ω.m. While the highest soil resistivity is 176.306 Ω.m on the right side of the substation with a 2-meter distance between each rod.

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Design new voltage balancing control series connected for HV-IGBT's

2021-08-01 , Fahmi M.I. , Mukmin M.F. , Liew Hui Fang , Wai C.L. , Aazmi M.A. , Syahrun Nizam Md Arshad @ Hashim

The insulated gate bipolar transistors (IGBTs) are widely used in various applications as they require low gate drive power and gate voltage. This paper proposes an active gain circuit to maintain voltage stability of series-connected IGBTs for high voltage applications. The novel gate driver circuit with closed-loops control amplifies the gate signal while restricting the IGBT emitter voltage below a predetermined level. With the proposed circuit, serial-connected IGBTs can replace high-voltage IGBTs (HV-IGBTs) for high-voltage applications through the active control of the gate signal time delay. Closed-loop controls function is to charged current to the gate to restrict the IGBT emitter voltage to a predetermined level. This paper also presents the experiment on the gate driver capability based on a series-connected IGBTs with three IGBTs and a snubber circuit. The experimental results show a voltage offset with active control with a wide variation in load and imbalance conditions. Lastly, the experimental results are validated with the simulation results, where the simulation results agree with the experimental results.

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First Principles Enhanced Electronic Band Structure of Back Contact in CdTe Solar Cells using DFT+U Method

2023-01-01 , Ahmad N.I. , Nurhafiza Azizan , Kar Y.B. , Doroody C. , Syahrun Nizam Md Arshad @ Hashim , Ahmad Zaidi Abdullah , Jamal A.

Cadmium telluride (CdTe) superstrate solar cells have captivated the industry with their remarkable cost-effectiveness. However, optimizing the composition and optoelectrical properties of optimal back surface field (BSF) which can act as a lattice matching interface between the back contact and absorber layer remains a key challenge due to the work function disparity of p-CdTe with metal contacts. In this study, the influence of the Hubbard U parameter on the calculated electronic properties of ZnTe as an optimal BSF compound is presented using the density functional theory (DFT) technique. The Hubbard U value progressively increased from 1 to 4.2 to analyze its influence on the band diagram and Total Density of States (TDOS) in a full comparison of DFT and DFT+U approaches. As the value of Hubbard U increased, the band gap energy exhibited a corresponding increase from 1.20 eV to 2.24 eV, respectively. In comparison, the DFT+U approach with a value of 4.2 exhibited superior accuracy in predicting the band gap of ZnTe, yielding a value of 2.24 eV that closely approximated experimental measurements. This finding reinforces the relevance of employing Hubbard U to achieve more accurate and reliable band gap values for any material doping.

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