Electrical and Electronics

Power system performance is a?ected by dynamic characteristics of hydraulic governor-turbines during and following any disturbance, such as occurrence of a fault, loss of a transmission line, a rapid change of load or hydraulic transients. Accurate modeling of hydraulic governor-turbines is essential to characterize and diagnose the system response during an emergency. In this paper, the identification/development and implementation of hydraulic systems in power plants via literature survey and computer based simulations have been described and it has been analyzed with comparing different models. This article examines the responses of different models through simulation in MATLAB/SIMULINK. The results obtained provide an insight into the interaction between electrical and hydraulic system of hydro power plant governed by di?erent governor settings, so that the system may remain unaffected during any disturbance.

This paper presents an improvement method for future smart electricity grid performance using high efficiency solar cells. The smart grid offers several advantages for the connection of solar (renewable) energy sources to provide an efficient operation and better performance of the power systems. Finite-difference time domain (FDTD) method is employed to simulate the light transmission, reflection and absorption of high efficiency solar cell structures. Simulation results show that the reflection loss is reduced with the use of nanostructures compared with the flat type substrates. Therefore, the proposed solar cells will inject more energy into the electricity grid and hence improving the overall system performance.

Zero crossing detection is the most common method for measuring the frequency or the period of a periodic signal. This paper presents a comparative study of various zero crossing detector techniques. The accuracy of measuring zero crossing for synchronizing power system control and instrumentation requires a diverse approach to minimize phase detection errors from signals corrupted with noise and extraneous signals. An approach to detect zero crossing with the use of opto coupler is detailed describe in the paper. The issues related to the previous approaches has been discussed along with their pros and cons.

In this study, comparison between two controllers i.e. PID controller and fuzzy logic controller is done for the proposed dc-dc closed loop boost converter. The simulation, modeling and stability analysis of DC-DC Boost converter for Solar Electric system is done using space averaging technique in order to study its time domain, frequency domain and pole-zero domain analysis. A feedback controller for DC-DC boost converter is Designed to obtain constant output voltage of 24 V.A fuzzy logic controller is later used to control the output voltage of the boost converter. Simulation results show that fuzzy logic controlled boost converter has fast transient response, better steady-state response, and the proposed converter is less sensitive to load changes as compared to that of PID controller.

This paper presents a photovoltaic array (PVA) simulation model to be used in Matlab-Simulink GUI environment. The model is developed using basic circuit equations of the photovoltaic (PV) solar cells including the effects of temperature changes and solar irradiation. This PVA model is used with boost converter to analyze its output and usage for various constant DC operations efficiently. Further an applications of solar panel of low output voltage is shown in which the panel is simulated with boost converter and then its output is given to an SVPWM fed inverter which provides 3 phase AC supply for 3 phase induction motor, which is feeding half of the industrial world. The advantage of using PID controller with closed loop converters is also shown in this paper, which provides constant DC. The simulation of closed loop converter with solar panel is done and the results are presented

MIMO techniques increases the spectral efficiency of the transmission and increasing capacity by using Spatial Multiplexing and Precoding. MIMO Spatial Multiplexing is the simultaneous use of the same frequencies to transmit independent data streams. Precoding (mixing) of the two streams is used to optimize the transmission into the channel so that the receiver has the best chance of recovering the original data streams. Several nonlinear precoding methods including dirty paper coding is used to achieve the capacity region for MIMO. In this paper capacity of the MIMO system and sum rate comparison is analyzed by suggesting a modified precoding technique and a round robin user scheduling algorithm.

An innovative concept of International Mobile Telecommunications – Advanced (IMT-Advanced) which is specified by the International Telecommunications Union – Radio Communication Sector (ITU-R), aims to perform a peak data rate of up to 1 Gbps for low mobility and 100 Mbps for high mobility. A study item on Long Term Evolution (LTE)-Advanced has been commenced to meet the above need by the 3rd Generation Partnership Project (3GPP), that supports the transmission over a much wider bandwidth than the LTE systems. The techniques for efficient resource allocation for LTE-Advanced systems with aggregation of multiple Component Carriers (CC) are deeply analyzed in this paper. Bandwidth based resource allocation using carrier load balancing methods like Round-robin, Mobile Hashing and Walsh code methods, have been used and their performance analysis is done in terms of the throughput and coverage. It proposes a cross component carrier packet scheduling algorithm for an effective resource allocation among the users with aggregation of component carrier in comparison with the independent packet scheduling per CC. To study the multi carrier system, Long Term Evolution (LTE)-Advanced users and LTE Rel’8 users are selected. The various carrier load balancing methods are compared based on independent and cross CC packet scheduling and then coverage performance, cell throughput and user throughput are analyzed with the help of Full buffer and finite buffer transmission system.

This paper presents an optimum design technique of broadband two elements Yagi array antenna. The optimization parameter for the proposed antenna is the impedance bandwidth using appropriate dimensions of ground plane and in Yagi array, dipole is replace by patch, all element design in form patch. In this paper we observed effect with and without ground plane on impedance bandwidth. Appropriate Spacing is used between elements; all elements designed on scale of reflector, the proposed antenna can be used for C-Band application. For validation of proposed geometry IE3D Simulator is used.

The advent of wireless communications both inside and outside the home-office environment has led to an increased demand for effective encryption systems. The beauty of encryption technology comes out in more pronounced way when there is no absolute relation between cipher and original data and it is possible to rebuild the original image in much easier way. As chaotic systems are known to be more random and non-predictable, they can be made utilized in achieving the encryption. The transposition technology of encryption systems requires scrambleness behaviour in order to achieve the encryption of the data. This srambleness behaviour can be derived from the randomness property of chaos which can be better utilized in the techniques like transposition system. In wireless communication systems, bandwidth utilization is an important criterion. In order to use encryption system in wireless communication; key space plays an important role for the efficient utilization of the bandwidth. In this paper we present a chaos-based encryption algorithm for images. This algorithm is based on pixel scrambling where inthe randomness of the chaos is made utilized to scramble the position of the data. The position of the data is scrambled in the order of randomness of the elements obtained from the chaotic map and again rearranged back to their original position in decryption process.

With the rapid increase in number of women suffering from breast cancer, it’s early detection aids in fast and effective treatment. Mammography, which is currently the most popular method of breast screening has some limitation and microwave imaging offers an attractive alteration. Microwave imaging is attractive due to high contrast in dielectric properties between cancerous and non-cancerous tissue. The paper presents different type of feeding mechanism to the micro strip patch antenna used in microwave imaging and its comparison in an urge of getting an ultra-wide band of 3GHz within the frequency range of 3.2 GHz to 10.6 GHz. The antenna is Designed and simulated using Ansoft High Frequency Structure Simulator (HFSS)