Electrical and Electronics

Voltage instability is the major concern of power system stability. It is caused due to the deficit of reactive power in the system. Improving the systems voltage by increasing the reactive power handling capacity of the system by using Static VAR Compensator, during a large disturbance is the area of study. The simulations are carried out for IEEE 14 bus system by using MATLAB/PSAT software. The result shows the effectiveness of SVC to improve the voltages when connected to a system.

In this work design and development of the conformal microstrip antenna array is demonstrated. Important system parameters and overall performance of the Array antenna is described and experimental results for reflection coefficients and far field patterns is included as well as simulated pattern and synthesis results .To improve the performance of microstrip antenna array, a modified configuration of microstrip series-fed taper array is designed. Compared to the traditional one, the novel antenna array has a better VSWR characteristic. The design procedure of the conformal antenna array is discussed and some valuable results are acquired. Numerical results are obtained and a very good agreement is observed between experimental and simulated results of such arrays.

For high bit rates and long haul optical communication systems using a single-mode fiber, a modulator with low chirp and small size are demanded. An electro-absorption modulator is very attractive because it has some advantages of not only low chirp and small size but also the elimination of polarization control through monolithic integration with a distributed feedback (DFB) laser. The modulation bandwidth of traditional lumped electro-absorption modulators (EAMs) is usually limited by the RC time constant, but the effective resistance R and capacitance C are not easily extracted for advanced device geometries. This paper has presented the important transmission characteristics of EA modulators such as transmission performance efficiency, insertion loss, extinction ratio, , over wide range of the affecting parameters for different selected electro-absorption materials to be the major of interest.

Sunlight based vitality frameworks have developed as a suitable wellspring of renewable vitality in the course of the last a few decades, and are currently generally utilized for an assortment of mechanical and household applications. Such frameworks depend on a sun oriented gatherer, intended to gather the sun's vitality and to change over it into either electrical power or warm vitality. When all is said in done, the power created in such applications depends on a very basic level upon the measure of sun powered vitality caught by the authority, and along these lines the issue of creating following plans equipped for taking after the direction of the sun over the span of the day on a year-round premise has gotten huge scope in this paper. In Aden city (Yemen), the change in the execution of a sun oriented cooker amid summer was observed to be as much as 40% for higher height edge and 70% for lower rise edge, in view of the created following calculations. Besides, it was demonstrated that the measure of sun based vitality caught by a tilted gatherer could be expanded by more than 40% by modifying the tilt point on a regular premise. Two LDRs are utilized to screen the sun powered light condition. These LDR yield is interfaced to Microcontroller through transistor. The controller consistently checks the voltage level of the LDRs and works the engine to confront the board to most extreme level of force. The day/night condition is additionally checked by these two LDRs to handicap the following in night condition. The engine is driven by H connect. This paper utilizes controlled 12V, 500mA power supply. 7805 three terminal voltage controller is utilized for voltage direction. Connect sort full wave rectifier is utilized to amend the air conditioner output of optional of 230/12V stage down transformer.

This paper presents the comparison of hybrid multilevel inverters for different voltage and power applications. Hybrid multilevel inverters improve the number of the output voltage level based on a hybrid connection of power cells. Therefore, a given number of levels can be synthesized by several multilevel configurations, significantly increasing flexibility and complexity in the design of hybrid multilevel inverter. The purpose of the circuits presented here is to minimize the reverse voltage stress and the harmonic distortion of the voltage applied to the load. As a characteristic of the proposed cells, some of the switches operate at low frequency while others are switched at high frequency. Different topologies are discussed and reviewed in brief. Voltage sharing and low output-voltage distortion are achieved. This paper presents a survey of different topologies, control strategies and modulation techniques used by these inverters.

An available gas fired diffusion-absorption heat pump 150 liter (5ft) refrigerator has been modified by substituting the original heat input by transferring solar thermal energy from solar collector to the generator. At the beginning, a pipe with 90cm height, filled with hot water (97oC) is used as a generator heat input but the Ammonia vapor does not generate because the temperature is low to allow Ammonia-Water mixture to boil. Therefore the Water is replaced by high boiling point fluid (liquid paraffin wax), boiling point 310°C), and the generator with pipe with 30cm height and 5cm in diameter. Then Ammonia vapor generates at fluid temperature of 140oC up to 190oC where the pipe near the condenser becomes hot. This mean that the Ammonia vapor generate up to the condenser. The flow rate required to supply heat input to generator, the solar collector receiver area and the volume of hot fluid storage required to operate the refrigerator for 24 hours has been calculated.

The proposed system presents power-control strategies of a grid-connected hybrid generation system with versatile power transfer. This hybrid system allows maximum utilization of freely available renewable energy sources like wind and photovoltaic energies. For this, an adaptive MPPT algorithm along with standard perturbs and observes method will be used for the system. Also, this configuration allows the two sources to supply the load separately or simultaneously depending on the availability of the energy sources. The turbine rotor speed is the main determinant of mechanical output from DG energy and Solar cell operating voltage in the case of output power from solar energy.The inverter converts the DC output from non-conventional energy into useful AC power for the connected load. In order to utilization distributed generation (DG) unit interfacing converters to actively compensate harmonics, this paper proposes an enhanced current control approach, which seamlessly integrates system harmonic mitigation capabilities with the primary DG power generation function. As the proposed current controller has two well- decoupled control branches to independently control fundamental and harmonic DG currents, local nonlinear load harmonic current detection and distribution system harmonic voltage detection are not necessary for the proposed harmonic compensation method. Moreover, a closed-loop power control scheme is employed to directly derive the fundamental current reference without using any phase-locked loops (PLL). The proposed power control scheme effectively eliminates the impacts of steady-state fundamental current tracking errors in the DG units. Thus, an accurate power control is realized even when the harmonic compensation functions are activated hybrid system operates under normal conditions which include normal room temperature in the case of solar. The simulation results are presented to illustrate the operating principle, feasibility and reliability of this proposed system.

Relevant background material about speech recognition is presented, along with a critical review of previous hardware implementations. Accurate real-time speech recognition is not currently possible in the mobile embedded space where the need for natural voice interfaces is clearly important. The continuous nature of speech recognition coupled with an inherently large working set creates significant cache interference with other processes. Hence, real-time recognition is problematic even on high-performance general-purpose platforms. This paper provides a detailed analysis of CMU's latest speech recognizer (Sphinx 3.2.). Several optimizations are then described which expose parallelism and drastically reduce the bandwidth and power requirements for real-time recognition. A special-purpose accelerator for the dominant Gaussian probability phase is developed for a 0:25_ CMOS process which is then analyzed and compared with Sphinx's measured energy and performance on a 0:13_ 2.4 GHz Pentium 4 system. The results show an improvement in power consumption by a factor of 29 at equivalent processing throughput. However after normalizing the process, the special-purpose approach has twice the throughput, and consumes 104 times less energy than the general-purpose processor. The energy-delay product is a better comparison metric due to the inherent design trade-offs between energy consumption and performance. The energy-delay product of the special-purpose approach is 196 times better than the Pentium 4. These results provide strong evidence that real-time large vocabulary speech recognition can be done within a power budget commensurate with embedded processing using today's technology.

This paper presents an advanced step to the concept of car black-box in developing a comprehensive vehicle safety system which would not only record the video and audio, but also try to prevent a possible collision by limiting the speed of the vehicle in accident-prone areas. In case of an accident, the time and location (co-ordinates) is sent through GSM to a preset number for immediate rescue and treatment of accident, also recorded data can be used for forensics which would reveal law enforcement authority about the failure that caused accident, and give manufacturer an idea for improvement. So the motto is to develop an embedded integrated system consisting of microcontroller, power supply unit, sensors, memory, motor driver unit and GPS/GSM modem.

MIMO technology plays a vital role in wireless communication which uses multiple antennas at both transmitter and receiver side. As the demand of data rate is increasing day by day, there is a need of high throughput, wide coverage, capacity and improved reliability. Integration of OFDM with MIMO holds the potential to drastically increase the data rate in future wireless communication system without increasing the transmit power and bandwidth. In this paper we mainly focus on the advantage of using MIMO-OFDM system and the drawback of using SISO, SIMO, MISO systems which have been verified using simulation. Performance of the systems is measured with respect to BER, capacity and finally the data rate is determined. The simulation results are obtained using MATLAB/SIMULINK software.