Electrical and Electronics

This paper describes three phase bi-directional battery charger widely used in Energy storage application. The full bridge scheme is widely used for the high power application. The high-frequency transformer is used for the isolation purpose. This paper describes the design and simulation of a 7.75-kW, full-bridge, bi-directional isolated dc-dc converter with active front-end converter (AFC). The AFC is connected with the 3-phase ac system, which provides 650 to 700 dc voltage to dc-dc converter with lower value of THD (according to IEEE- 915) and improve power factor at input side. The dc-dc converter converts 310V from 650V for charging the battery. Software tool PSIM is used to obtain the simulation result of the converter. The closed loop system is simulated to achieved voltage and current ripple at output side less than 1% rms of rated voltage.

In this brief, a reconfigurable IDCT architecture is designed for multistandard inverse transform. The proposed architecture is used in multistandard decoder of MPEG-2, MPEG-4 ASP, H.264/AVC and VC-1. Two circuits share strategies, factor share (FS) and adder share (AS), are applied to the inverse transform architecture for saving its circuit resource.

Nowadays it is of major importance to monitor and collect information about the environment and there are several instances wherein the environs are not conducive to human presence. For underwater pipeline monitoring, detection of enemy submarines, exploration of marine life, search and rescue operations, and surveillance in hazardous environments, it is necessary to develop an unmanned remote controlled vehicle which can do all the required functions. Considering terrains under water and on land, an amphibious robot is best suited for these kinds of activities. The amphibious robot (R-CAR) designed is capable of moving on land as well as on water. It swims with the help of its flaps, rather than using conventional thrusters and control surfaces for propulsion. Through an appropriate set of gaits, this robot is capable of translatory and rotatory motion in the open water. Wheels are attached for movement on land. This robot is controlled by Dual Tone Multi Frequency (DTMF) tones produced by a mobile phone which acts as a remote. These tones are then transmitted by a transmitter-encoder module. The receiver-decoder pair placed inside the robot receives and decodes the signal to detect what key the user has pressed. This signal is then received by an on-board microcontroller which is programmed to drive the powerful servo motors by pulse width modulation. The hydro dynamically designed flaps are fastened to the servo motors which provide movement to this robot. All the electronic circuitry is enclosed in streamlined water sealed enclosure. For movement on land, wheels are driven by the DC motors which are programmed by the microcontroller. The robot was found to move satisfactorily on land as well as in water as per the design.

Rising demands on engine performance, fuel consumption, emission, etc. leads to study thermal behavior of cooling system in engines precisely. To minimize the time of 3-D numerical simulation, single phase boiling approach was used. Sub-cooled boiling heat transfer consists of two components (i.e. forced convection and boiling). The convective component is evaluated from flow analyses and to evaluate boiling heat transfer, two popular models, Chen and BDL, are considered. To study sub-cooled boiling heat transfer in engine cooling passages, a rectangular, bottom-heated, horizontal duct is simulated here to assess the effects of different working conditions (i.e. pressure, velocity and coolant type) on heat transfer. Comparing the numerical results with the experimental ones reveals that Chen model is more precise than BDL in predicting boiling heat transfer in engine cooling system.

An implementation of quarter – squarer multiplication using op-amps is described. It uses op-amp based dual squaring circuits. It eliminates the drawback of MOSFETs based quarter squarer multiplier. Verification of the feasibility of circuit configuration is established by way of test results on a proto type.

The goal of this research is to discover the most appropriate approach for finding the reflection and transmission coefficients of the dominant mode scattering by a circular dielectric/ferrite cylindrical post in a rectangular waveguide and to generalize this approach so that it can be applied to the case of the layered posts as well. Microwave waveguide post filters are practically useful and the procedure of filter synthesis using dielectric/ferrite posts requires a solution to the inverse scattering problem. Typically, an algorithm for solving the inverse scattering problem requires a lot of computation time, because in each iteration it has to solve a number of forward problems. To speed up a process of a solution of the inverse problem it is required to find an approach that provides the small computation time. The problem can be solved by using some flexible methods, such as finite element method, finite difference method and finite difference method in the time domain [1] or software based on these methods such as HFSS or Ansys. Despite great flexibility of these methods, they, require a great amount of computation time. Using some geometrical properties that reduce computational effort by solving a part of problem by analytical means or at least by converting a problem to its simpler equivalent it is possible to reduce numerical effort considerably.

Steganography is skill of hiding secret messages or hiding secret images so that only the writer and the intended recipient are aware from hidden information .Steganography is an powerful technique in terms of any type of carrier which is hiding technique that develops stimulating structures to fruitfully & successfully hide information (may be a text or an image ) in color images. Digital steganography is basically about hiding a file in, or adding a file to, another file, called the carrier file, such that the carrier file is not changed enough to raise suspicion that something may be concealed within it or appended to it. The steganography scheme on hardware platform shows huge potential by means of various advantages such as high speed implanting, specific hardware dependency, and low power consumption etc. Current developments favor using digital images, carrier files as the cover file to hide another file that contains the secret information in the form of either text or image that means carrier file. Hardware stenographic modules applied in a processor platform like FPGA which offer some essential additions to the existing benefits of software based stego systems. It also offers the Embedding rate which is very high when compared to the systems in software domain. LSB method representing a high imbedding capacity.

A three notch multilayer antenna for C-Band applications is presented in this paper. The proposed antenna is composed of a FR-4 and air gap Dielectric material, By introducing the two parts, the impedance bandwidth of the antenna can be significantly enhanced. Analysis done with ground plan. Simulation results show that the proposed antenna can operate from 3.2GHz to 4.8 GHz with low VSWRs ? 2. Stable antenna gain (dB) is also achieved over the entire operating frequency band. Furthermore, the size of the proposed antenna is very compact, which is only at the centre of the operating frequency band.

Constant Instantaneous Power Control technique for extracting reference currents for shunt active power filters has been assessed for 400Hz aircraft electric power system. Thereafter, its performance has been compared when optimized using fuzzy logic control. Critical analysis of Comparisons of the compensation ability of these two techniques based on THD and compensation time will be done and suggestions will be given for the selection of best technique to be used. The simulated results using MATLAB model are presented. That will prove the importance of the proposed control method of aircraft shunt SAF in aviation industry.

In this paper output force controlling for three degree freedom (DOF) surgical robotic arm by using genetic algorithm with PID controller. The aim of the controller is to improve and adjust the output force of the arm and optimization parameters such as kp, ki and kd by Genetic Algorithm without hid and trail method is taken. The optimization design methods often consider the system requirements for quickness, reliability, and accuracy. This robot is used in the field of surgery. So surgical robotic arm require don’t oscillate and no max. Overshoot. This paper performs to reduce the oscillation, max. Overshoot, settling time and improves stability of system.