Motilal Nehru National Institute of Technology Allahabad

About: Motilal Nehru National Institute of Technology Allahabad is a education organization based out in Allahabad, Uttar Pradesh, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 2475 authors who have published 5067 publications receiving 61891 citations. The organization is also known as: NIT Allahabad & Motilal Nehru Regional Engineering College.

Tailoring of enhanced interfacial polarization in WO3 nanorods grown over reduced graphene oxide synthesized by a one-step hydrothermal method

Abstract: In the present report, well-defined WO3 nanorods (NRs) and a rGO–WO3 composite were successfully synthesized using a one-pot hydrothermal method. The crystal phase, structural morphology, shape, and size of the as-synthesized samples were studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. The optical properties of the synthesized samples were investigated by Raman, ultraviolet-visible (UV-Vis) and photoluminescence (PL) spectroscopy. Raman spectroscopy and TEM results validate the formation of WO3 (NRs) on the rGO sheet. The value of the dielectric constant (e′) of WO3 NRs and rGO–WO3 composite is decreased with an increase in frequency. At low frequency (2.5 to 3.5 Hz), the value of e′ for the rGO–WO3 composite is greater than that of pure WO3 NRs. This could be due to the fact that the induced charges follow the ac signal. However, at higher frequency (3.4 to 6.0), the value of e′ for the rGO–WO3 composite is less compared to that of the pure WO3 NRs. The overall decrease in the value of e′ could be due to the occurrence of a polarization process at the interface of the rGO sheet and WO3 NRs. Enhanced interfacial polarization in the rGO–WO3 composite is observed, which may be attributed to the presence of polar functional groups on the rGO sheet. These functional groups trap charge carriers at the interface, resulting in an enhancement of the interfacial polarization. The value of the dielectric modulus is also calculated to further confirm this enhancement. The values of the ac conductivity of the WO3 NRs and rGO–WO3 composite were calculated as a function of the frequency. The greater value of the ac conductivity in the rGO–WO3 composite compared to that of the WO3 NRs confirms the restoration of the sp2 network during the in situ synthesis of the rGO–WO3 composite, which is well supported by the results obtained by Raman spectroscopy.

FRS-DAB Converter for Elimination of Circulation Power Flow at Input and Output Ends

Abstract: Dual active bridge (DAB) converter is the most suitable converter to transfer high power with bidirectional power flow capability and isolation. However, it has the drawbacks of circulation power flow (CPF) and limited range of zero voltage switching (ZVS). To overcome these drawbacks, several modulation strategies have been proposed; however, the CPF can be eliminated either at input or output voltage ends. In order to eliminate the CPF at both input and output sides, a novel front and rear end switch DAB (FRS-DAB) bidirectional dc–dc converter has been proposed in this paper. It has the advantages of lower current stress, extension of ZVS range, higher power transfer capacity, and improved efficiency compared to the conventional DAB converter. The paper presents the detailed operating modes and analysis of power flow control for the proposed FRS-DAB converter. The operation and analytical results of the proposed converter have been verified through the experimental results using an FPGA Spartan 3AN processor.