oalib

OALib Journal期刊

ISSN: 2333-9721

费用：99美元

投稿

时间不限

( 2673 )

( 2672 )

( 2024 )

( 2023 )

自定义范围…

匹配条件： “Rama Reddy Sathi” ，找到相关结果约5602条。
列表显示的所有文章，均可免费获取
第1页/共5602条
每页显示 条
Embedded Controlled Isolated Bidirectional Full-Bridge DC-DC Converter with Flyback Snubber
D. Kirubakaran,Rama Reddy Sathi
Advances in Power Electronics , 2012, DOI: 10.1155/2012/730473
Abstract: An isolated bidirectional full-bridge DC-DC converter with flyback snubber for supplying a resistive load is simulated and experimentally verified. The DC-DC converter for high conversion ratio, high output power, and soft start-up capability is presented in this paper. The circuit consists of a capacitor, a diode, and a flyback converter. These components help to clamp the voltage spikes caused by the current difference between the current fed inductor and leakage inductance of the isolation transformer. The switches are operated by soft-switching technology. The suppression of inrush current which is usually found in the boost mode start-up transition is presented here. The simulated and experimental results for output voltage, output current, and power for both buck and boost modes are presented. 1. Introduction A DC-DC converter converts a source of direct current(DC) from onevoltagelevel to another. These converters are important in portable electronic devices such as cellular phonesandlaptop computers, which are supplied with power from batteries primarily. The ordinary circuit of a DC-DC converter for high power applications typically includes a bidirectional full-bridge DC-DC converter [1–3]. The current difference between the inductor and isolation transformer does not ensure a well-defined output voltage and is characterized by less reliability and efficiency. The output voltage contains voltage spikes. An active commutation can be used to control the current in the leakage inductance [4]. But it requires an additional clamping circuit to suppress the voltage spikes. An RCD passive snubber can be used to clamp the voltage. A buck converter was employed to replace RCD snubber. But it still needed complex clamping circuit [5, 6]. Active clamping increases the current stress on switches. Soft-switching capability can be used, but it is not suitable for step-down operation. In this scheme of DC-DC converter with flyback snubber (Figure 1), the snubber recycles the absorbed energy in the clamping capacitor. The voltage of the clamping capacitor can be regulated by operating the flyback snubber independently. The current does not circulate through the full-bridge switches, and hence the current stress can be reduced, improving the system reliability significantly. Figure 1: Isolated bidirectional full-bridge Dc-Dc converter with flyback snubber. 2. Configuration and Operation The operating principle of the circuit consists of two modes: (i)step-up conversion,(ii)step-down conversion. The modes of operation of boost mode are shown in Figure 2 and of
Analysis and Design of Embedded Controlled Parallel Resonant Converter
P. CHANDRASEKHAR,Sathi Rama REDDY
Annals of Dunarea de Jos , 2009,
Abstract: Microcontroller based constant frequency controlled full bridge LC parallel resonant converter is presented in this paper for electrolyser application. An electrolyser is a part of renewable energy system which generates hydrogen from water electrolysis. The DC power required by the electrolyser system is supplied by the DC-DC converter. Owing to operation under constant frequency, the filter designs are simplified and utilization of magnetic components is improved. This converter has advantages like high power density, low EMI and reduced switching stresses. DC-DC converter system is simulated using MATLAB, Simulink. Detailed simulation results are presented. The simulation results are compared with the experimental results.
Neural network based PWM AC chopper fed induction motor drive
Venkatesan Jamuna,Sathi Reddy Rama
Serbian Journal of Electrical Engineering , 2009, DOI: 10.2298/sjee0902299v
Abstract: In this paper, a new Simulink model for a neural network controlled PWM AC chopper fed single phase induction motor is proposed. Closed loop speed control is achieved using a neural network controller. To maintain a constant fluid flow with a variation in pressure head, drives like fan and pump are operated with closed loop speed control. The need to improve the quality and reliability of the drive circuit has increased because of the growing demand for improving the performance of motor drives. With the increased availability of MOSFET's and IGBT's, PWM converters can be used efficiently in low and medium power applications. From the simulation studies, it is seen that the PWM AC chopper has a better harmonic spectrum and lesser copper loss than the Phase controlled AC chopper. It is observed that the drive system with the proposed model produces better dynamic performance, reduced overshoot and fast transient response. .
Primary aneurysmal bone cyst of patella
Reddy N,Sathi Venkata
Indian Journal of Orthopaedics , 2009,
Abstract: O0 f all the aneurysmal bone cysts (ABC) occurring in the body, less than 1% are seen in the patella. We report here, a 27-year-old woman with Stage III ABC of patella. Curettage, chemical and thermal cautery of the bed followed by autogenous bone grafting of the defect was done. At two-year follow up, there was a suspicion of lucency in the middle of the patella. However a repeat curettage revealed only fibrous tissue. Now at four years of follow up, the bone graft remained well incorporated. Patient has mild anterior knee pain on stair climbing but regained normal knee function.
Three Party Quantum Authenticated Key Distribution Protocol Using Superposition States
K. Sathi Reddy,Raja Kumar Medapati
International Journal of Computer Technology and Applications , 2011,
Abstract: This paper presents a Quantum authenticated key distribution protocol that can perform key distribution and also ensure that the participants of the communication are authentic, both implicitly and explicitly. This protocol provides new directions in Classical cryptography and Quantum cryptography.The Participants of the protocol trust the third party regarding the authentication part only. Thus the proposed protocol will be preferable for network systems which deal with highly sensitive information, such as military, hospitals, research facilities. Our protocol utilizes polarized photons in superposition states for authentication and key distribution which provides high security against many attacks.
Natural Convective Boundary Layer Flow over a Horizontal Plate Embedded in a Porous Medium Saturated with a Nanofluid  [PDF]
Rama Subba Reddy Gorla, Ali Chamkha
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.22011
Abstract: A boundary layer analysis is presented for the natural convection past a horizontal plate in a porous medium saturated with a nano fluid. Numerical results for friction factor, surface heat transfer rate and mass transfer rate have been presented for parametric variations of the buoyancy ratio parameter Nr, Brownian motion parameter Nb, thermophoresis parameter Nt and Lewis number Le. The dependency of the friction factor, surface heat transfer rate (Nusselt number) and mass transfer rate on these parameters has been discussed.
Feasibilty of Wind-Solar Hybrid System for Cleveland, Ohio, USA  [PDF]
Rama Subba Reddy Gorla, Rashid Salako
Smart Grid and Renewable Energy (SGRE) , 2011, DOI: 10.4236/sgre.2011.21005
Abstract: The most promising and most feasible application of solar-wind hybrid energy is in the area of space and service water heating. Since these heating processes require only moderate temperatures, they can be easily achieved by the use of low-cost flat-plate collectors and low cut-in wind turbines. As the heating of buildings and provision of hot water account for a very significant percent of the total energy consumption in Cleveland, the diversion of these energy demands to solar-wind hybrid energy would result in a substantial relief of our dependence on fossil fuels and other forms of energy resources.
Grating Lobe Suppression with Element Count Optimization in Planar Antenna Array  [PDF]
B. Rama Sanjeeva Reddy, D. Vakula
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2015, DOI: 10.4236/jemaa.2015.72004
Abstract: The novel approach of this paper describes the suppression of grating lobe level with the element count optimization in planar antenna array. Rectangular lattice (RL) and triangular lattice (TL) structures are chosen for determining the achievable array element patterns (EP) and further suppressing the grating lobe level. The element spacing and number of elements (10 × 20 array) are taken into account for particular lattice. Grating lobe peaks are observed for the 200-element planar array at maximum scan angle (θ) with the set frequency of 3 GHz. Further, it is found that 14°; bore sight elevation of rectangular lattice produces a transformed field of view, which permits a reduction in element count of 20.39% compared with 10° bore sight elevation. Finally, the typical values of elevation, element count and array size (25 cm2) are trained using artificial neural network (ANN) algorithm and element count is predicted after testing the network. The network shows a high success rate.
Second Law Analysis of Mixed Convection in a Laminar, Non-Newtonian Fluid Flow through a Vertical Channel
Rama Subba Reddy Gorla
ISRN Applied Mathematics , 2011, DOI: 10.5402/2011/287691
Abstract:
Copper oxide nanoparticles induces oxidative stress and liver toxicity in rats following oral exposure
Rama Narsimha Reddy Anreddy
- , 2018, DOI: 10.1016/j.toxrep.2018.08.022
Abstract: The present study aimed to evaluate the effect of Copper Oxide (CuO) Nanoparticles (NP) on liver following oral exposure in rats. A total of 18 male wister rats were used in the experiments including a control group (6 rats). NP were given to the rats with a doses (5, 50？mg/kg b.w./day) via oral gavage and a control group (received only 200？μl PBS). The treatment was continued for 14 days. The supernatants of rat Liver tissue homogenates were used to analyze for glutathione levels (GSH), Catalase, superoxide dismutase (SOD), the extent of lipid peroxidation products (Malondialdehyde, MDA). Oral administration of NP to rats caused a significant (P？<？0.05) dose dependent alterations in antioxidant enzyme activities. Data results clearly showed the significant decrease (p？<？0.05) in GSH, Catalase (CAT) and SOD activity, whereas the lipid peroxidation product (MDA) levels were increased (p？<？0.05). In conclusion, oral exposure of CuO nanoparticles to rats causes significant toxicity to the liver and it might be due to oxidative stress
第1页/共5602条
每页显示 条


Home
Copyright © 2008-2020 Open Access Library. All rights reserved.