Browsing by Author "Mallikarjuna, B."

Now showing 1 - 4 of 4

Analysis of Wireless Charging System for Low-Power Appliances
(Institute of Electrical and Electronics Engineers Inc., 2024) Mangamuri, R.; Kuriti, C.S.; Divvi, S.S.; Mallikarjuna, B.; Kishan, D.
Wireless power transfer stands out as a transformative technology that provides a hassle-free, secure, and effective method for charging of power appliances without the constraints of cables. In this paper, performance analysis of a wireless mobile charging system (lower power appliances) based on a well-established principle electromagnetic induction has been carried out. The system comprises transmitter and receiver circuits featuring wireless power transfer coils. These coils are designed and simulations using ANSYS Maxwell software to analyze the impact of coil misalignment on mutual inductance and coupling coefficient variations of the wireless charging system. The electromagnetic coupled coils are deployed in a charging circuit model designed in MATLAB/Simulink model to demonstrate its dynamic behaviour, showcasing the system's capability to generate a stable 5 V DC voltage for lower power appliances. This study highlights the practicality of optimizing the design of wireless charging system. Â© 2024 IEEE.
Characterization and thermal analysis of laser metal deposited ?-TiAl thin walls
(Elsevier Editora Ltda, 2021) Mallikarjuna, B.; Bontha, S.; Krishna, P.; Balla, V.K.
The present work focuses on investigating the effect of process variables (power, travel speed, powder flow rate) on microstructure and mechanical properties of Laser Metal Deposited (LMD) ?-TiAl thin walls. To this end, LMD technique was used to deposit ?-TiAl thin walls at different processing conditions. Microstructures of as-deposited samples were investigated using both optical and scanning electron microscopy. X-ray diffraction (XRD) technique was used to determine the phases present. Microhardness measurements were carried out along both longitudinal and build directions. Microstructural analysis of as-deposited samples revealed a fine lamellar structure comprising of ? and ?2 phases. Colony size of 30–60 ?m and lamellar spacing between 0.1 and 0.7 ?m were observed. XRD analysis confirmed the presence of ? and ?2 phases. Comparison of elemental analysis results on both powder and as-deposited samples revealed a negligible loss of Al and no oxygen pick up in the deposited thin walls. Hardness values were found to decrease with an increase in wall height, and hardness values increased marginally (5%) with an increase in travel speed. Further, 3D transient thermal analysis was also carried out to complement the LMD of thin walls in terms of melt pools and cooling rates. It was found that the melt pool depth (MPDc = 0.266 mm) is smaller at the centre than the edge (MPDe = 0.513 mm) of the wall. A higher cooling rate of 1.05 × 105 °C/s near the wall substrate was found for 200–12. © 2021
Design of a Multi-Mode DC-DC Converter for High-Power Wireless Charging of Electric Vehicles
(Institute of Electrical and Electronics Engineers Inc., 2024) Kishan, D.; Mallikarjuna, B.; Ahmad, M.W.; Chub, A.
The design of high-power wireless power transfer (WPT) systems has been the subject of substantial research due to the increasing demand for fast, efficient, and effective battery charging methods for electric vehicle (EV) customers. This paper proposes a DC-DC converter capable of operating in three distinct modes. It incorporates an H6-Bridge inverter, which can be configured as half bridge-half bridge (HB-HB), half bridge-full bridge (HB-FB), and full bridge-full bridge (FB-FB), and is connected through LCC-Series networks to a dedicated H6-Bridge configuration. This innovative design enables efficient charging of EVs with battery voltage classes ranging from 400V to 800V without affecting the current ratings of the converter's components. Furthermore, the paper presents an analysis of an equivalent circuit WPT system for battery packs with output voltages of 400V, 600V, and 800V. To validate its effectiveness, a 7.2 kW power converter with a 600V input and a variable output range from 400V to 800V was simulated, achieving an impressive maximum efficiency of 94.2% across a wide spectrum of output voltages. Â© 2024 IEEE.
Experimental investigation on additive manufactured single and curved double layered microchannel heat sink with nanofluids
(Springer Science and Business Media Deutschland GmbH, 2023) Narendran, G.; Mallikarjuna, B.; Nagesha, B.K.; Gnanasekaran, N.
For the latest high density compact devices, thermal management is crucial for their effective heat dissipation and system reliability. In literature, microchannel heat sink has been established as one of the advanced heat transfer techniques to fulfill the cooling demands of high power electronic applications. However, maldistribution in microchannels causes flow induced high temperature zones (FITZ) which reduces the electrical performance owing to electrical-thermal instability of the integrated chips. One way to mitigate the FITZ is by allowing more coolant inlets in these zones. In the current study, this is achieved by redesigning double layer microchannel heat sink (DMCHS) specific to the FITZ of I-type microchannel configuration using additive manufacturing (AM). Two AM microchannels were tested, one is a single layer microchannel heat sink (MCHS) and another one is a curved double layer microchannel (C-DMCHS). The curved channels were introduced in the bottom channels of C-DMCHS to mitigate FITZ compared to conventional DMCHS. AM microchannels are compared for Nusselt number and friction factor characteristics with the conventional straight channels, and heat treated AM microchannels. From experimental observation, Ti64 3D printed microchannel with Graphene oxide (GO-0.12%) nanofluid developed 75.4% more pressure drop than the Ti64 heat treated microchannel. The results additionally show that the C-DMCHS delivered 26.5% lower FITZ temperature than MCHS. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.