i-manager's Journal on Electrical Engineering (JEE)


Volume 5 Issue 3 January - March 2012

Research Paper

Enhancement Of Power Transmission CapabilityOf VSC-HVDC System Using Fuzzy Controller

M. Ramesh * , A. Jaya Laxmi**
* Associate Professor, Department of EEE, Medak College of Engineering and Technology, Kondapak
** Associate Professor, Department of EEE, Jawaharlal Nehru Technological University, Kukatpally, Hyderabad.
M. Ramesh and A. Jaya Laxmi (2012). Enhancement Of Power Transmission Capability Of VSC-HVDC System Using Fuzzy Controller. i-manager’s Journal on Electrical Engineering, 5(3), 1-8. https://doi.org/10.26634/jee.5.3.1710

Abstract

In planning and operating today’s stressed power systems, the ability to maintain voltage stability has become a growing concern. Although the term voltage stability is being extensively used in the literature and in industry, general agreement on exactly what constitutes voltage stability does not yet exist. This is largely because distinctions between phenomena which represent different forms of instability are often subtle. Also, the physical aspects of voltage instability may not be well understood due to the complex nature of the phenomenon and the variety of ways in which it can manifest itself in power systems. Recently, due to advancement of power electronics technology, High Voltage Direct Current (HVDC) transmission technology has been utilized to enhance power system stability. The HVDC is very reliable, flexible and cost effective. Advances in artificial intelligence techniques such as Fuzzy, ANN etc. and Power Semiconductor devices have made tremendous impact in the improvement stability of HVDC system. A case is made to present overview of the artificial intelligence techniques   possibility of including these techniques in modern power system and practices.

Research Paper

Comparison between Direct Control Method and Indirect Control Method of Non Linear Sliding Mode Controller for DC-DC Buck Converter

G.S. Rajanna* , H.N. Nagaraj**
* Research Scholar, Department of Electrical & Electronics Engineering, JNTU, Hyderabad.
** Principal, AIT &M VTU, Belgaum.
G.S. Rajanna and H.N. Nagaraj (2012). Comparison Between Direct Control Method And Indirect Control Method Of Non Linear Sliding Mode Controller For DC-DC Buck Converter. i-manager’s Journal on Electrical Engineering, 5(3), 9-15. https://doi.org/10.26634/jee.5.3.1733

Abstract

A major disadvantage of applying sliding mode control (SMC) to dc-dc buck converter is that switching frequency is affected by line and load variations. To maintained constant switching frequency, two different methods incorporated to design a sliding mode controller for dc-dc buck converter is presented in this paper. The first method is called direct SMC, employed as a general sliding mode control (SMC) with hysteresis method to suppress the switching frequency in which output of SMC controller is applied directly to power switch. The second method, Indirect sliding mode control, is based on the modified integral variable structure control (MIVSC), in which the output of the SMC controller applied to the switch through Pulse width modulation (PWM). Two methods are compared by simulation (MATLAB/SIMULINK). The result gives that the indirect SMC is able to suppress the switching frequency and exhibits better load and line disturbance rejection than the direct SMC control method.

Research Paper

Dynamic Improvement of Distributed Generators Connected To Distribution Networks Using DSTATCOM

P. Harshavardhan Redd* , J.N. Chandra Sekhar**, Mareddy Padma Lalitha***
* Assistant Professor, Department of EEE, Annamacharya Institute of Technology and Sciences, Rajampet.
** Assistant Professor, Department of Electrical and Electronics Engineering, S.V.U. College of Engineering, S.V.University, Tirupathi.
*** Professor and HOD, Department of Electrical and Electronics Engineering, Annamacharya Institute of Technology and Sciences, Rajampet.
P. Harshavardhan Reddy, J.N. Chandra Sekhar and M. Padma Lalitha (2012). Dynamic Improvement Of Distributed Generators Connected To Distribution Networks Using DSTATCOM. i-manager’s Journal on Electrical Engineering, 5(3), 16-22. https://doi.org/10.26634/jee.5.3.1738

Abstract

This paper presents a dynamic study about the influences of distributed generators (induction and synchronous machines) and distribution static synchronous compensator (DSTATCOM) devices on the dynamic behavior of distribution networks. The performance of a DSTATCOM as a voltage controller or a power factor controller is analyzed.  The impacts of these controllers on the stability and the protection of the system with distributed generators are studied. Simulation is to be carried out using DSTATCOM as voltage controller and power factor controller.

Research Paper

Single Phase Induction Motor Drives for Low Power Applications

Karpagam* , A. Nirmal Kumar**, M. Suresh***
* Associate Professor, Department of Electrical and Electronics Engineering, Jansons Institute of Technology, Coimbatore, Tamil Nadu.
** Professor and Head, Department of Electrical and Electronics Engineering, Info Institute of Engineering, Coimbatore, Tamil Nadu.
*** Assistant Professor, School of Electrical Sciences, Department of Electrical and Electronics Engineering,Kongu Engineering College, Erode, Tamil Nadu.
J. Karpagam, A. Nirmal Kumar and M. Suresh (2012). Single Phase Induction Motor Drives For Low Power Applications. i-manager’s Journal on Electrical Engineering, 5(3), 23-30. https://doi.org/10.26634/jee.5.3.1739

Abstract

Single-phase induction motors are widely used in fractional power applications such as fans, refrigerators and air conditioners. An improvement in its performance means a great saving in electrical energy.The motor can be operated at constant speed or controlled by ON/OFF strategy which results in poor performance and low power factor.An inverter-fed variable frequency motor is a typical example of such improvement. Nowadays, a direct AC-to-AC converter commonly termed as Matrix Converter has a simple structure and many attractive features. These converters have the characteristics such as four quadrant operation, unity input power factor, no dc-link capacitor and high quality voltage/current waveforms. Matrix Converters are replacing the conventional Voltage Source Inverters. In this regard, this paper presents a comprehensive analysis of the performance of the single-phase induction motor when it is fed with single phase inverters and matrix converters. Sinusoidal Pulse Width Modulation (SPWM) technique is used to generate the firing pulses for power switches of the inverter and matrix converter. Simulations were done using MATLAB/Simulink software package and the results were analyzed and presented.

Research Paper

Harmonic Elimination Using Pattern Search Method

M. Narayanan* , K. Keerthivasan**, Jovitha JeromeJ***
* Assistant Professor, Department of Electrical and Electronics Engineering, Karpagam University, Coimbatore, India.
** Associate Professor, Department of Electrical and Electronics Engineering, Karpagam University, Coimbatore, India.
*** Professor, Department of Electrical and Instrumentation and Control Engineering, PSG college of Technology, Coimbatore, India.
M. Narayanan, K. Keerthivasan and Jovitha Jerome (2012). Harmonic Elimination Using Pattern Search Method. i-manager’s Journal on Electrical Engineering, 5(3), 31-36. https://doi.org/10.26634/jee.5.3.1742

Abstract

The problem of low power factor, power loss, heating of the machine and telephonic interference necessitates techniques to eliminate harmonics. The main objective of harmonic elimination is to produce the fundamental while not generating specifically chosen harmonics. The output voltage waveform of an inverter is given by Fourier series expansion which contains both the fundamental and the harmonics. Suitable technique has to be used to solve the transcendental equation. Traditional optimization methods suffer from various drawbacks, such as prolonged and tedious computational steps and convergence to local optima, thus, the more the number of harmonics to be eliminated, the larger the computational complexity and time. So in this research work, Pattern Search (PS) method has been employed to eliminate the harmonics. Using pattern search technique, the transcendental equations are solved and switching times (angles) that produce only the fundamental without generating any specific harmonic order is found. This is referred to as harmonic elimination or programmed harmonic elimination as the switching angles are chosen (programmed) to eliminate specific harmonics.

Research Paper

Parallel Resonant Full Bridge Isolated AC-DC ZVS Converter

V Sivachidambaranathan* , Subhransu Sekhar Dash**
* Research Scholar, Sathyabama University, Chennai.
** Professor & Head, SRM University, Chennai.
Sivachidambaranathan V and Subhransu Sekhar Dash (2012). Parallel Resonant Full Bridge Isolated AC-DC ZVS Converter. i-manager’s Journal on Electrical Engineering, 5(3), 37-42. https://doi.org/10.26634/jee.5.3.1744

Abstract

Resonant power converters have many advantages over Pulse Width Modulation (PWM) power converters, such as lower switching losses at higher switching frequencies, easier EMI filtering, reduced component stress and higher efficiency. High switching loss considerably reduces the converter efficiency. The use of soft-switching techniques, alleviate switching loss problems and allow a significant increase in the converter switching frequency. At increased frequency the converter can employ smaller sized magnetic elements and filter components. Most of the switching losses are eliminated Resonant Converters. The advantages of Parallel Resonant Converter (PRC) are that the output dc filter capacitor does not carry high ripple current and also it exhibits good voltage regulation. In the present work Parallel Resonant Converter (PRC) with Zero Voltage Switching (ZVS) for the 12 V DC output is designed with High Frequency (HF) and the simulation results are presented.

Research Paper

DSP Implementation Of SVM Based Open Loop V/Hz Control Of Induction Motor

J. Chandrakala* , Y.P. Obulesu**, Penchalababu V***
*-** Assistant Professor, Lakireddy Bali Reddy College of Engineering, EEE Department, Vijayawada, India.
*** Research scholar, Sri Vasavi College of Engineering, EEE Department, Tadepalligudem, India.
Chandrakala B,Y.P. Obulesu and Penchalababu V (2012). DSP Implementation Of Svm Based Open Loop V/Hz Control Of Induction Motor. i-manager’s Journal on Electrical Engineering, 5(3), 43-48. https://doi.org/10.26634/jee.5.3.1746

Abstract

Voltage-source inverters with space vector PWM strategy are gaining importance in high power high performance industrial applications. This paper presents open loop V/HZ control of induction motor drive based space vector pulse width modulation (SVPWM) technique. The proposed system has been implemented using DSP (TMS320F2812) controller and demonstrated through hardware and simulation results. From the results it shows that this system makes a good performance on motor control.

Research Paper

A Novel Direct Torque Control Of Sensorless Induction Motor Drive With Reduced Flux And Torque Ripple

R. Rajendran* , N. Devarajan**
* Assistant Professor, Department of IT, Karpagam College of Engineering, Coimbatore.
** Professor, Department of EEE, Government College of Technology, Coimbatore.
R. Rajendran and N. Devarajan (2012). A Novel Direct Torque Control Of Sensorless Induction Motor Drive With Reduced Flux And Torque Ripple. i-manager’s Journal on Electrical Engineering, 5(3), 49-53. https://doi.org/10.26634/jee.5.3.1748

Abstract

In this paper simulation of a novel Space Vector Modulated Direct Torque Control (DTC-SVM) of sensorless induction motor is presented. Classical direct torque control (DTC) of induction motor drive is simple in nature and known to produce quick response but there is usually undesired torque and flux ripple. This paper introduces an improved flux and torque estimator based DTC-SVM which has a low-pass filter based voltage model with compensations of amplitude and phase. The proposed scheme is able to reduce the flux and torque ripple significantly while maintaining the simplicity and robustness of conventional DTC at the most.