Electrical and Electronics

The high growth of the semiconductor industry over the past two decades has put Very Large Scale Integration in demand all over the world. Digital Signal Processing has played a great role in expanding VLSI device area. The recent rapid advancements in multimedia computing and high speed wired and wireless communications made DSP to grab increased attention.For an N-point transformation the direct computation of the Discrete Fourier Transform (DFT) requires N2 operations. Cooley and Turkey explained the concept of Fast Fourier Transform (FFT) which reduces the order of computation to Nlog¬2N. The FFT is not an approximation of the DFT, it's exactly equal to the DFT. FFT decomposes the set of data to be transformed into a series of smaller data sets to be transformed. The size of FFT decomposition is called "radix". Then, it decomposes those smaller sets into even smaller sets. At each stage of processing, the results of the previous stage are combined with twiddle factor multiplication. Finally, FFT is calculated for each small data set. Generally, FFT's can be decomposed using DFT's of even and odd points, which is called a Decimation-In-Time (DIT) FFT, or they can be decomposed using a first-half/second-half approach, which is called a "Decimation-In-Frequency" (DIF) FFT.A large number of FFT algorithms have been developed, but among all radix-4 are most widely used for practical applications due to their simple architecture, with constant butterfly geometry and the possibility of performing them ‘in place’. The algorithm for 16-point radix-4 FFT can be implemented with decimation either in time or frequency. In this work, the decimation in time (DIT) technique will be adopted in order to implement the 16-point radix-4 FFT.

Self-Organizing Map (SOM) can be used to quickly create a qualitative overview of the data. It maps nonlinear statistical relationships among different variables of a high dimensional input data on a low dimensional network, preserving most of the topographic relationships from the input space. Hence, for dealing the complex problem of separation of incipient faults of highly overlapping nature, an epistemological decision making approach using SOM is proposed in this paper.

This paper presents the non-linear control of an induction motor (IM). The objective of nonlinear control is to can control separately flux and the speed, several techniques of control are used for (IM), The technique of control oriented flux (FOC) which permits the decoupling between input and output variables, so (IM) is assimilate to continuous current motor , this method has a problem is how exactly oriented the axis d on the flux .However, feedback linearization amounts to cancelling the nonlinearities in a nonlinear system so that the closed- loop (CL) dynamics is in a linear form . A goal of feedback linearization is to can controlled separately flux and the speed ,the motor model is strongly nonlinear then it’s composed to the autonomous and mono-variables too under systems so every under system presented an independence loop of control for each variables is given . The space vector modulation [SVM] method gives a good tracking for the non linear control, SVM became a standard for the switching power converters and important research effort has been dedicated, tens of papers, research reports and patents were developed in the theory of space vector modulation.

Environmental friendly energy system is going to develop compared to convectional primary energy due to energy security problems. As the cost of solar energy is zero, the demand of solar energy is gradually increased in different purposes such as electricity, cooling and so on. Moreover, in the energy market, Photovoltaic (PV) inverters bear a very important role due to cost and efficiency. Hence, Transformer (TRX)-less inverter system is part and parcel where possible to reduce the overall system cost, size with high efficiency. In this review paper, different TRX-less inverter topologies are focused with the different switching conditions and the process of Leakage Current Reduction (LCR). Here is shown the basic concept of PV panel, flow chart according to the review papers, different leakage current paths and the mitigation processes.

A significant increase of the electrical equipment in modern aircrafts is leading to an increase in the demand for electrical power. The usual electrical power distribution in aircraft applications is done via a three-phase 415 Vac grid. A new trend of DC distribution is emerging employing a 270 Vdc grid. With the advancement in the power semiconductor devices and power transformers, DC-DC converters are designed with frequency ranging up to MHZ range. Increase in the switching frequency along with the sudden change in the current di/dt or voltage dv/dt generates higher order harmonics which leads to Electro Magnetic Interference (EMI). EMI noise creates malfunctioning of the circuit and also leads to miscommunication within the system and sometimes leads to device failure. Which is an undesirable condition as far as airline is considered. Hence the reduction of EMI noise is of uttermost important. This paper focus on the reduction of EMI using passive filter along with modified PWM carrier modulation technique. A circuit model for the prediction of conducted emissions due to DC/DC converters in an aircraft black box system is proposed and corresponding attenuation method is been analyzed.

This paper presents a new approach to the Automatic detection and classification of electrocardiogram (ECG) signals is of huge importance for diagnosis of cardiac abnormalities. A method is proposed here to classify different cardiac abnormalities like Ventricular Arrythmias, Myocardial infarction,Myocardial hypertrophy and Valvular heart disease. Support Vector Machine (SVM) has been used to classify the patterns inherent in the features extracted through Continuous Wavelet Transform (CWT) of different ECG signals. CWT allows a time domain signal to be transformed into time-frequency domain such that frequency characteristics and the location of particular features in a time series may be highlighted simultaneously. Thus it allows accurate extraction of feature from non-stationary signals like ECG. Then the support vector machine (SVM) with Gaussian kernel is used to classify different ECG heart rhythm. In the present work, SVM in regression mode has been successfully applied for the classification of cardiac abnormalities with good diagnostic accuracy.

This paper deals with the simulation of three, five, seven and nine level output using H- bridge inverter. This paper presents H – bridge inverter simulated using MATLAB with different levels (like three, five, seven and nine level). The percentage (%) total harmonic distortion THD is calculated. The harmonic reduction is achieved by selecting appropriate switching angles. The functionality verification of the three level, five level, seven level and nine level output is done using MATLAB.

The identification of linear structures are done in geophysical images. The problem of identification of curvilinear structures in real and synthetic geophysical images is faced for the first time. Here we propose a method for automatic enhancement and detection of curvilinear structures. The accurate identification of line structures in geophysical images plays an important role in geophysical interpretation and the detection of subsurface structures. The method was applied on geophysical images in an effort to recognize the linear patterns of subsurface architectural structures that exist in archaeological sites. The method efficiently combines a rotation and Scale-invariant filter and a pixel-labelling method, providing a robust enhancement and detection of mostly line structures in 2-D gray scale images. Mainly they are used in archaeological sites.

Gradual development in power systems has caused so many problems in control and optimum using of electrical storage systems. Storing of electrical energy has made new capabilities in improving the current control methods. Quick access to these kinds of energies lets us direct control for supplying the consumers in electrical grid network. These methods are powerful to control and solve the current economical and technical problems of the compound and large power systems. On the other hand, using the various methods of direct energy storage can produce suitable capacity to store the electrical energy for the power industry. Among all of the energy storage systems, pumped storage power plants when they committed, because of their special characteristics, have a unique situation. In this paper, the feasibility assessment of the usage of pumped storage power plants for the Iranian grid has been discussed by WASP-IV program.

Various applications, like in underground mines and oil and gas industries, require remote operation of vector-controlled medium-voltage variable speed drives via a long motor feeder. The use of voltage source inverters in such cases leads to motor overvoltage and harmonic quality problems. The current source inverter (CSI) is ideally matched to these applications be-cause of its motor-friendly voltage output. Speed sensorless operation is mandatory due to the long motor feeder. Although the model reference adaptive system (MRAS) is a powerful and proven speed estimation tool, its implementation in long motor feeder drives faces many challenges. Among them, and addressed in this paper, are inherent dc offset in its stator model, the need for actual motor voltage and current values, and oscillations in the estimated speed due to errors in the motor current measurement signals. In this paper, a sensorless CSI vector-controlled drive, suitable for long motor feeder applications, is studied. Improved speed estimation is achieved by proposing 1) a modified dc-offset eliminator for an MRAS speed estimation and 2) a compensation technique for mo-tor current’s measurement errors. Intensive experimental results, for a low-voltage scaled model, along with simulations validate the effectiveness of the proposed technique. In this Proposed Control technique of the space vector modulation Technique (SVPWM) is applied to 5 level inverter controls in the proposed DTC_SVPWM based induction motor drive system, thereby dramatically reducing the torque ripple. Then the controller based on space vector modulation is designed to be applied in the control of Induction Motor (IM) with a three-level Inverter. This type of Inverter has Several advantages over the standard Five-level CSI, such as a greater number of levels in the output voltage waveforms, Lower dv/dt, less harmonic distortion in voltage and current waveforms and lower switching frequencies Eliminated By SVPWM Tech. simulation results are reported to demonstrate its effectiveness. The entire control scheme is implemented with Matlab/Simulink.