Electrical and Electronics

This paper provides the designing of mosfet with different materials and compare which material is better for the designing. In previous time the mosfet is design by the combination of silicon and silicon oxide now we are using gallium arsenide and silicon dioxide as one combination and gallium arsenide and silicon nitride as another combination.

The need for renewable energy sources is on the rise because of the acute energy crisis in the world today. India plans to produce 20 Gigawatts of Solar power by the year 2020, whereas we have only realized less than half a Gigawatt of our potential as of March 2010. Solar energy is a vital untapped resource in a tropical country like ours. The main hindrance for the penetration and reach of solar PV systems is their low efficiency and high capital cost. To maximize a photovoltaic (PV) system's output power, continuously tracking the maximum power point (MPP) of the system is necessary. Maximum power point tracking (MPPT) is a technique that grid tie inverters, solar battery chargers and similar devices use to get the maximum possible power from one or more solar panels. Solar cells have a complex relationship between solar irradiation, temperature and total resistance that produces a non-linear output efficiency known as the I-V curve. It is the purpose of the MPPT system to sample the output of the cells and apply the proper resistance (load) to obtain maximum power for any given environmental conditions. Maximum power point tracking (MPPT) algorithms provide the theoretical means to achieve the MPP of solar panels; these algorithms can be realized in many different forms of hardware and software.

Maximum power point trackers (MPPTs) play a vital role in photovoltaic (PV) systems because they increase the efficiency of the solar photovoltaic system by increasing the power output. MPPT algorithms are necessary because PV arrays have a non linear voltage-current characteristic with a unique point where the power produced is maximum. The output power from the solar panel varies with solar irradiance, temperature and so on. To increase the power extracted from the solar panel, it is necessary to operate the photovoltaic (PV) system at the maximum power point (MPP). This paper presents the Matlab/simulink arrangement of perturb & observe (P&O) and incremental conductance (INC) MPPT algorithm which is responsible for driving the dc-dc boost converter to track maximum power point (MPP). This paper also presents the theoretical analysis of variable step size (VSS) of INC MPPT which can effectively improve the tracking speed and accuracy of maximum power.

Differential Evolutionary Algorithm is a simple but powerful computing tool for real parameter optimization. This article describes the application of this technique for designing a PID controller for Electromagnetic levitation system (EMLS).EMLS is inherently unstable and strongly non-linear in nature. Classical controllers designed for this system give no satisfactory performance. Little change in the operating air gap position deteriorates the controller performance making the system unstable. Therefore a need arises to make one controller such that it will give the optimum performance in the sense of changing gap positions .To that end Differential Evolutionary Algorithm (DEA) is used to fulfil this goal. The analysis is performed within the mathematical programming environment of MATLAB using both DEA and Conventional Genetic Algorithm (CGA) and a detailed comparative study is presented.

Nowadays traffic are very high near the signals to overcome long time IR sensors are used. These IR sensors are placed near the junction it senses the heavy traffic in that signals switches to green to make move on that heavy traffic vehicles. By implementing this the wastage of time can be reduced on the roads.

The power dissipation in a system-level attributes to buses is increasing in VLSI circuits. Therefore reduce of power consumption in switching activity at the I/O ports can save significant save of power. Change of voltage level on the wires significant power consumptions. As the technology scaled down, the increased wire aspect ratio (height/width) reduce the spacing between individual bus wires. This resulted in the domination of coupling capacitance. There are so many techniques have been proposed to reduce the coupling activity along with the self-switching activity. Initially, Bus invert method can be applied to encode buses without prior knowledge of data statistics. Another encoding technique called “Sequence Switch Coding for low-power data transmission” (SSC) was proposed by Myungchul Yoon to minimize Self Transition activity in buses. Among the Bus Invert method and Sequence Switch Coding, the Bus Invert method has gained popularity because of its better energy reduction (upto25.45%). However, both Bus Inver and SSC bus encoding techniques reduce only self transitions and do not consider the effect of coupling transitions. Therefore, it is important to minimize the power dissipation and cross talk delay by minimizing the both self transitions and coupling transitions on bus for the fast and safe VLSI circuits. A new technique isintroduced by doing some modifications to existing SSC technique given by Myungchul Yoon et.al, to reduce the energy dissipation and delay on DSM bus through encoding the data on the bus.

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.