Journal of Electrical & Electronic Systems

This paper presents the investigations on the effect of wind energy system’s participation on dynamic stability margins available on AGC of interconnected power system. A two area power system model interconnected via EHVAC tie-line is considered for the study. Each of the areas is consisting of hybrid sources of power generation like; hydro, thermal, gas and wind power plants. Various participation factors for electrical energy received from wind power plants, along with the energy from thermal, gas and hydro plants, are considered for the investigations. Moreover, any reduction of generation from thermal power plant is supposed to be supplied by wind power plant for fuel saving and to reduce emissions to environment. The optimal AGC regulators are designed using full state vector feedback control theory. Following the achievement of optimal gains of AGC regulators, the system closed-loop system eigenvalues are obtained for various case studies. The investigations of the closed loop eigenvalues carried out reveal that all the closed-loop eigenvalues are lying in the negative half of s-plan for all case studies and thus ensure the closed-loop system stability. Also, closed-loop eigenvalues are found to be sensitive to reduction in thermal generation and subsequent increase in electrical energy from wind power plants. It is also observed that the computed complex eigenvalues have shown a considerable decrease in the magnitude of its imaginary part when reduction of thermal generation is met by wind power generation. The reduced magnitudes of imaginary parts of closed-loop eigenvalues result in cost effective controller realization and improvement in system stability. On the other hand, the replacing the deficit caused in the supply with wind energy has no undesirable emissions to environment.

Thin films of microcrystalline silicon (μc-Si) were deposited by (LPCVD: Low Pression Chemical Vapour Deposition) to realise Au-μcSi Schottky diodes which are powerful devices to determine several μc-Si characteristic parameters which are never obtained with simple layers without serious difficulties. Therefore, good quality Schottky devices have been successfully made and present an excellent reproducibility. The current voltage (I-V) characteristics of these devices have given an ideality factor (n) in the range (1.5-2) and a barrier height Ф(I-V) between 0.63 and 0.97eV. This last parameter was found lower than the barrier height Ф(C-V) deduced from the capacitance-voltage characteristics (C-2-V). This difference is attributed to the existence of insulated interface layer as several other authors.

Under the discipline I have discussed about a concept to generate electricity using the gravitational force. A structure which is able to work itself for generating electricity, basic concept behind this is to utilize the structural and gravity both. A general structure and its arrangement for generation, various other aspects or application for the structure is being discussed.

Simultaneous acquisition of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) aims to combine the strength of both methods by investigating brain activity with the high temporal resolution of the former and the good spatial precision of the later. However, simultaneous EEG-fMRI measurements are technically challenging because both methods interfere with the other modality. The main confounding factors are the pulse artefact (PA) caused by pulsatile motion linked to the cardiac cycle and the gradient artefact (GA) produced by the temporally varying magnetic fields required for MR imaging. Both of these artefacts are orders of magnitude larger than the neuronal activity of interest, but their inherent periodicity facilitates reasonable artefact correction by post-processing techniques such as average artefact subtraction (AAS), Optimal Basis Set (OBS). While the different post processing methods for PA artefact are being used to-date, but their comparison were not studied yet. In this work, different methods - OBS, simple mean (AAS) and Gaussian-weighted mean (GWM) - implemented in open source FMRIB tool-box, were used for PA correction and to compare their performance in artefact correction while retaining the neuronal information. It has been found that, of the three different PA removal methods, OBS is better in preserving bio-signal while removing PA successfully.

In this paper a low power delay locked loop with a closed loop duty cycle corrector is proposed. The duty cycle corrector circuit is a dual loop circuit which receives a clock signal with 30%~70% duty cycle and generates a clock signal with 50% ± 2% duty cycle. The power consumption of the overall circuit is 1.2 mW. This circuit is fabricated in 0.18 um CMOS technology. Measurement results show that the RMS jitter of the proposed work is 4 ps at 1 GHz.

High-dose-rate (HDR) brachytherapy is an effective internal radiation therapy procedure for treating malignant neoplasms. This technique is widely used in breast cancer treatments to destroy residual cancer cells surrounding the lumpectomy cavity following surgery. This is done by inserting a balloon catheter into the cavity that is inflated with saline as well as a medium of radiographic contrast. Then the radioactive isotope is positioned into the center of the balloon using an HDR unit to deliver the prescribed dose to a volume surrounding the balloon. Most of the currently available treatment planning systems (TPS) for brachytherapy, including Nucletron Oncentra, estimate dose using proprietary algorithms which use a pre-calculated dose metric derived from Ir-192 placed in a water phantom. However, they do not take into account variations in attenuation due to inhomogeneities in different tissues. This may lead to several questions: do these TPS estimate absorbed dose correctly within the target tissue? What are the effects on breast-air interface within the target volume? Does a radiographic contrast medium in the balloon alter the dose distribution calculated by TPS? These uncertainties and doses can be quantified by using the data recorded in a tissueequivalent patient phantom which is aided by a PN junction commercial diode detector and an electrometer. During this investigation, we used a cubical water phantom and Mammosite® single lumen balloon system to measure effects on breast-air interface, the diode detector was placed on the phantom wall to simulate the tissue air interface. Measured data were compared with predictions from the Oncentra TPS for the same geometry. These results may help quantify uncertainties in the predicted versus actual skin doses used during the treatments. This in turn could increase the clinicians’ predictive power regarding potential excessive skin dose that could cause toxicity in patients.

The nonlinear dynamics of an autonomous chaotic oscillator, using two different stages operational amplifier coupled by mean of diode employed as the nonlinear device, recently introduced by Giannakopoulos and Deliyannis is considered with some particular modifications. These modifications are necessary for generating new type of oscillations, the regular and chaotic pulse oscillations according to the nature of operational amplifiers. Based on the nonlinear diode equation, the transfer voltage function of operational amplifiers in open loop configuration, and an appropriate selection of the state variables, a mathematical model is derived for a better description of the dynamics of the system. The complexness of oscillations is characterized using the bifurcation diagrams and the phase portraits. Some PSPICE simulations of the nonlinear dynamics of the oscillator are presented in order to confirm the ability of the oscillator to generate both the regular and chaotic pulse oscillations, according to the appropriate choice of its components.

Nowadays power quality is the most important issues in distributed power grids. Hysteresis current is one of the factors that reduce power quality in grid. This paper describes a hysteresis current controller inverter with application of a grid-connected PV system with application of LCL filter. The aim of this project is to reduce the hysteresis current magnitude and its THD by three levels PV gride connected inverter and remain in steady state inverter while reducing the switching frequency, reduces the losses. In addition, we add to this inverter, L filter and next time add LCL filter. We observe the function of each of them on the hysteresis current control. In fact, reducing hysteresis current causes improves power quality and final aim of this project is to improve the power quality of distribution network. This control method provides, unity power factor, load harmonic distortion reduction and reduce hysteresis current amplitude to 2.2 A. So by this method we improved power quality of distributed grid. This system uses one of the main sources of renewable energy. In this paper we want to do a complete simulation for hysteresis current control software using MATLAB / SIMULINK and SIM POWER toolbars.

Present paper proposes a power measurement technique of a single phase electrical load. The proposed method is a low cost power measurement technique. The load which is taken into consideration is either resistive load such as bulb or inductive load like single phase induction motor. This method is based on a low cost analogue IC (AD633) which does the analogue multiplication of the two input signals. In fact, AD633 is well suited for applications such as power measurement, modulation and demodulation, automatic gain control, voltage-controlled amplifiers, and frequency doublers. In present work AD633 is employed for power measurement. The AD633 output voltage give the multiplication of corresponding current and voltage signals of the load and produces pulsating signal/voltage at the double of the supply frequency. The higher frequency output of AD633 is attenuated by a low pass filer of an appropriate cut-off frequency (90 Hz). The corresponding DC component of the multiplier IC output obtained at the output of the active RC low- pass filter is found to be proportional to the average load power consumed. The output of RC low pass filter was plotted against different values of load using MATLAB code. The linearity of these plots was checked through the linear curve fit and the original plots for the validation purposes.

The ultimate purpose of this paper is to develop a remote controlled security door using a microcontroller. It is a means of enforcing security features of the entire building structure, equipped with appropriate management control. In this paper we have designed system that allows unlocking a secure door remotely. The main aim of this paper is to help users improve the door security of sensitive locations, from car parks, shopping centres or corporate head offices to airports, banks or nuclear power plants. This paper takes a cursory look at other security methods of controlling access, their disadvantages and then goes on to the design of the hardware as well as software programming to lock or unlock the door. Both software and hardware for the system were developed in this paper by using microcontrollers, relays, sensors, induction motors and some mechanical system to demonstrate the response of the output and input devices.

When there is a packet loss in given network, it cannot change the route all by itself. Administrator manually have to configure the given network and thereby provide access to the router which has efficient route to the client. By using Hot standby routing Protocol (HSRP), it automatically configures the router (also called auto redundancy) which is facing user traffic, with router which has highest priority after active router. It is enabled through HSRP. It reduces network congestion and enables soft operation. We use Open short path first (OSPF) protocol in this project as it has higher convergence rate which leads to very less packet loss. Based on the IP address present in the IP packet header, OSPF transmits the packets. Our main agenda of the project is to reduce packet loss and provide efficient transport of information to the clients who expect more accuracy round the clock and also provide auto redundancy, low cost.