Load compensation for diesel generator system by using DSTATCOM and 1/z controller

Vol.6 No.1

Year: 2012

Issue: Jul-Sep

Title: Load compensation for diesel generator system by using DSTATCOM and 1/z controller   

Author Name: Mr.K.J.SINU SINU, Dr.M.SHANKAR   

Synopsis:   

This paper presents simulation and hardware implementation of Load compensation by using DSTATCOM. This proposed DSTATCOM systems includes 1/z controller algorithm for control the system. Contributions are made in several aspects of the whole system, including inverter design, system simulation, controller programming, and experimental setup. The algorithm used for Load compensation by using DSTATCOM is the 1/z controller algorithm. In this method the error current can be measure and compare with reference current to achieve maximum power quality and maximum power deliver to source to load. The DSTATCOM consists of a inverter circuit, which is supposed to operate as the main part of the system, a three phase inverter is used. It provides the opportunity to have either higher or lower output voltage compared with the output. The resultant system is capable of load compensation by using DSTATCOM and obtained high power quality. The 1/z controller algorithm is used to compare error current with reference current and gives gate pulses to the inverter circuit. MATLAB and Simulink were employed for simulation studies. Experimental results indicate the feasibility and improved functionality of the system.

                       

  

 

HVDS approach for reducing the Technical and Non-technical losses to enhance the Electrical Distribution System performance

Vol.6 No.1

Year: 2012

Issue: Jul-Sep

Title: HVDS approach for reducing the Technical and Non-technical losses to enhance the Electrical Distribution System performance   

Author Name: Dr P Ravi Babu, Sushma B , Ashwin Kumar B                                                            

Synopsis:   

This paper presents a new methodology for enhancing the distribution system performance by minimizing both technical and non technical losses. Most of the utility companies in developing countries are victims of major revenue losses due to technical and non technical energy losses. The non technical losses are like electricity theft, unauthorized connections, irregular billing and the technical losses are I­­­2R power losses. These losses affect the quality of supply in terms of voltage magnitude, and more tariffs imposed on genuine customers. To improve the efficiency of supply, one of the recommendations is “Boosting the distributor phase voltage, say from 100% to 152% that is, 230V to 350V and stepping down to normal operating voltage (230V) at the consumer premises by using a special voltage regulator device”. The methodology can reduce the technical and non technical losses in the electrical distribution system up to 36.12% of total power supplied to electrical distribution system. Hence the voltage profile can be improved by reducing the I­­­2R losses. As the normal operating voltage of any home appliances is 230V, in the proposed methodology the electrical distributor phase voltage is maintained up to 350V.So if any domestic consumer tries to get unauthorized/illegal power tapping connection, the home appliances are get damaged due to over voltage. Hence, with this approach there is no chance for power theft or unauthorized connections in the distribution system. When the electrical distributor operates with more voltage than the normal operating voltage, the I2R losses in the distributor will be reduced considerably.

 

A Paper ON Bidding Strategy in an Open Access of Indian Electricity Power Market: An Overview and Key Issues

Vol.6 No.1

Year: 2012

Issue: Jul-Sep

Title: A Paper ON Bidding Strategy in an Open Access of Indian Electricity Power Market: An Overview and Key Issues   

Author Name: V.Madhu Sudana Reddy, B. Subramanyam   

Synopsis:   

The main intention of Bidding strategies is to run the system in free and fair manner with desired quantity of power to the consumer’s at most economical price through safe, secure and reliable operation of the power system. Bidding arrangement is properly designed in every country to take care of other abuse of market; these arrangements are kept on changing from time to time depending on the requirement for transparent and non-discriminatory electricity market. In this paper Bidding Strategy of Indian Power Markets, important Key Issues, Electricity Act’s and Challenges in this field are analyzed and also explain about calculation of MCP (Rs/MWh) and Volume (MW) with the help of IEX on-line data.

 

Enhancement of the Maximum Loading of Distribution Systems Using Genetic Algorithm

Vol.6 No.1

Year: 2012

Issue: Jul-Sep

Title: Enhancement of the Maximum Loading of Distribution Systems Using Genetic Algorithm   

Author Name: venkata prasad, S. Sivanagaraju , T.Ramana   

Synopsis:   

It is very important to determine the loading of distribution network because it helps in distribution system planning and network reconfiguration etc. In this paper enhancement of maximum loading of radial distribution feeders using genetic algorithm is proposed. The enhancement is done by the optimal conductor selection of radial distribution system. The effect of load models on the enhancement of maximum loading is also investigated. The load growth period is also considered in the investigation. With the proposed method optimal set of conductors are selected by maintaining acceptable voltage limits and current carrying capacity of the feeders. The effectiveness of the proposed method is illustrated with 32-node practical radial distribution system. The proposed method will reduce the real and reactive power losses and also improves the voltage profile.

 

Five Level VSI Based Statcom In Fourteen Bus System

Vol.6 No.1

Year: 2012

Issue: Jul-Sep

Title: Five Level VSI Based Statcom In Fourteen Bus System   

Author Name: S.D.Sundarsingh Jebaseelan, Dr.R.Raja Prabu   

Synopsis:   

This paper deals with the performance of fourteen bus systems with and without STATCOM using five level inverter VSI circuit. The VSI is extremely fast in response to reactive power change. A Static Compensator (STATCOM) is a device that can provide reactive support to a bus. It consists of voltage source inverters connected to an energy storage device on one side and to the power system on the other. STATCOM is a device which can supply the required reactive power at low values of bus voltage and can also absorb active power if it has large energy storage. It also required having less harmonic contents in the output and higher compensation VA capacity. When the reactive power of the load is changing continuously, a suitable fast response compensator is needed. STATCOM, TCTC, UPFC, TCSC, SVC are the compensators belonging to FACTS devices. Models for the STATCOM is developed using MATLAB simulink. The simulation of the STATCOM is performed in the Simulink environment and the results are presented.

 

Modeling and study of a standalone PV system using MATLAB/SIMULINK

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: Modeling and study of a standalone PV system using MATLAB/SIMULINK   

Author Name: MOHAMMED ASLAM HUSAIN, M Faisal Jalil , M Tabish S Beg , M Naseem , Abu Tariq   

Synopsis:   

The paper presents the modeling of a standalone PV system in Matlab/Simulink environment. The PV model is developed using basic circuit equations of the photovoltaic (PV) solar cells including the effects of solar irradiation and temperature changes. A DC/DC buck converter is used to decrease the array voltage to that of battery and connected DC load. The buck converter is controlled to extract the maximum power output of PV panel. The equations of the model are presented in details. Firstly the mathematical modeling of a solar cell is done, then how a solar module, array and panel is obtained using that cell is shown clearly. Different characteristics of cell, module, and array have been obtained for different parameters. Secondly a standalone model of PV system in modeled and analyzed. Solar PV panel is a nonlinear power source that needs accurate identification of optimal operating point. It is desired to operate Solar Photo Voltaic (SPV) panel at its maximum power output for economic reasons. This paper is useful to model, simulate and study the effect of changing ambient conditions of a standalone PV system.

    

New Control Technique Applied in Dynamic Voltage Restorer for balanced and unbalanced Voltage Sag /swell

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: New Control Technique Applied in Dynamic Voltage Restorer for balanced and unbalanced Voltage Sag /swell   

Author Name: S.Deepa, S. Rajapandian   

Synopsis:   

Dynamic Voltage Restorer (DVR) is a custom power device used in power distribution networks to protect consumers from sudden sags and swells in grid voltage. This paper discussed abc to dq0 base new control algorithm to generate the pulse. The proposed control scheme is simple to design and has excellent voltage compensation capabilities. Effectiveness of proposed technique is investigated through computer simulation by using MATLAB/SIMULNK software. The simulation results have shown validation of the control system

   

Suppression Of Very Fast Transient Over Voltages Across Insulating Flange Of UHV GIS

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: Suppression Of Very Fast Transient Over Voltages Across Insulating Flange Of UHV GIS  

Author Name: A. Raghu Ram, Jinka Amarnath , Dr.Kamakshaiah

Synopsis:   

In gas insulated substations (GIS), very fast transient over voltages (VFTO) are generated due to disconnector switching operations, disconnector switches (DS) are primarily used to isolate the       operating sectioning of HV insulation from each other as safety measure, vary fast transient over voltage(VFTO)  at  an  insulating  flange   are generated due to propagation of VFTOs on the conductor of a gas bus in GIS. Generation of VFTOs cases sparkovers across the insulating flange  of  high  pressure  oil  filled  cable/GIS interface. The ionized  path formed by spark over creates  low  impedance  path  for power frequency  fault  current  due  to  disconnector switching, resulting in flange damaged  with serious  consequences. This  paper  deals  the generation  of  VFTOs  across  the  insulating flange   and   suppressions   of   VFTOs   with shunting bars, capacitors across the flange for the  providing  potential  have  been  analyzed and reported in MATLAB 7.0.

  

A New Improved Fuzzy Logic Based Power System Stabilizer

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: A New Improved Fuzzy Logic Based Power System Stabilizer  

Author Name: SABAPATHI D, R. Anita   

Synopsis:   

Power System Stabilizer (PSS) is installed in the Automatic Voltage Regulator (AVR) of the generator, it must be capable of providing appropriate stabilization signals over a broad range of operating conditions and disturbances. Traditional PSS relay on robust linear design methods. In order to eliminate to cover a wide range of operating conditions, expert or rule based controllers have also been proposed. Fuzzy logic as a robust control design method has shown promising results. In this paper, a systematic approach to fuzzy logic control design is proposed.  This paper presents a study of Fuzzy Logic Power System Stabilizer (FLPSS) for stability enhancement of a two-area four-machine system. In order to accomplish the stability enhancement, speed deviation (??) and acceleration power deviation (?p) of the rotor synchronous generator have been taken as the inputs to the fuzzy logic controller. These variables show significant effects on damping the generator shaft mechanical oscillations. The stabilizing signals have been computed using fuzzy membership function depending on these variables. The performance of the system with FLPSS is compared with Conventional Power System Stabilizer (CPSS) and the system with PSS.

Transmission Loss Allocation in Transaction Frame-work using Genetic Algorithm

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: Transmission Loss Allocation in Transaction Frame-work using Genetic Algorithm   

Author Name: S.V.N.L.Lalitha, Maheswarapu Sydulu   

Synopsis:   

Using a physical flow based approach, power injected at a bus can be expressed as a product of transaction amounts and transaction co-efficients for all buses except slack bus. Since the slack bus has to compensate for the system losses, transaction co-efficients corresponding to system slack bus include an additional component to account for the loss and thus necessitate the need to be calculated iteratively. This paper proposes a Zbus method for direct determination of the loss allocation among transactions provided the transaction co-efficients are known. An attempt is made to find the transaction co-efficients corresponding to slack bus using Genetic Algorithm (GA). Case study is performed on IEEE 24 bus RTS with multiple transactions and the test results are compared with the results of existing methods.  

Induction Machine Bearing Fault Diagnosis With Discrete Wavelet Transform Using Vibration Signal

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: Induction Machine Bearing Fault Diagnosis With Discrete Wavelet Transform Using Vibration Signal   

Author Name: Ashwani Kumar Chandel, Raj Kumar Patel   

Synopsis:   

Condition monitoring and fault diagnosis of electrical machinery are of great concern in industries. Pre fault detection in machinery can save millions of rupee required as emergency maintenance cost. In the present paper a methodology for the diagnosis of bearing faults in an induction machine has been given. The proposed discrete wavelet transform methodology extracts principal features from vibration signals caused by the faulty bearings and subsequently analyse these for determining the type of fault. The discrete wavelet transform is fed with the accelerometer signals and it is found that the impulses appear periodically with time period corresponding to defect frequencies. The results thus obtained reveal that the proposed pre-faults detection method is very efficient and effective.

Power Control Scheme of Zero Headed Power Generation by SVPWM Technique

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: A Novel Power Control Scheme of Zero Headed Power Generation by SVPWM Technique   

Author Name: Sriharsha Yeswant, K. Narasimha Raju   

Synopsis:   

This paper presents an approach to the Power Regulatory Scheme for the Zero Headed Power Generation. In this scheme the system is mathematically modeled and is simulated in MATLAB. In Zero Headed Power Generation Scheme a Helical Turbine, which harnesses kinetic Energy of hydro Currents of water into Mechanical Energy, is used. The Mechanical Energy thus created is converted in to Electrical Energy by Synchronous Generator.  The mathematical equation for the Helical Turbine is obtained and the synchronous generator is mathematically modeled and the generator specifications regarding to 150KW are specified. The output power from the synchronous generator is regulated by control circuit with the help of SVPWM technique [1]. The controller is used for the variations in the flow rate of water. A closed loop control loop is designed to obtain standard voltage and standard frequency by PI Controller logic. The system has been simulated for with and without controller and the results are compared.

Design of Optimal Reduced Order Observer for Three- Area Load Frequency Control in a Deregulated Environment Interconnected with HVDC Link

Vol.5 No.4

Year: 2012

Issue: Apr-Jun

Title: Design of Optimal Reduced Order Observer for Three- Area Load Frequency Control in a Deregulated Environment Interconnected with HVDC Link   

Author Name: T. Anilkumar, Dr.N.Venkataramana   

Synopsis:   

This paper presents a reduced order observer solve load frequency control problem in a three-area deregulated environment when interconnected with HVDC link. The performance of the proposed method is compared with optimal state feedback controller. This proposed control strategy can estimate measurable state variables as well as it gives good dynamic response as a controller.

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

Vol.5 No.3

Year: 2012                

Issue: Jan-Mar

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

Author Name: R. Rajendran, N. Devarajan   

Synopsis:   

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.

 

 

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

Vol.5 No.3

Year: 2012                

Issue: Jan-Mar

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

Author Name: Chandrakala, Y.P. Obulesu , Penchalababu   

Synopsis:   

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.

 

Parallel Resonant Full Bridge Isolated AC-DC ZVS Converter

Vol.5 No.3

Year: 2012                

Issue: Jan-Mar

Title: Parallel Resonant Full Bridge Isolated AC-DC ZVS Converter   

Author Name: Sivachidambaranathan, Subhransu Sekhar Dash   

Synopsis:   

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.

Harmonic Elimination Using Pattern Search Method

Vol.5 No.3

Year: 2012                

Issue: Jan-Mar

Title: Harmonic Elimination Using Pattern Search Method   

Author Name: M. Narayanan, K. Keerthivasan , Jovitha Jerome   

Synopsis:   

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.

Single Phase Induction Motor Drives for Low Power Applications

Vol.5 No.3

Year: 2012                

Issue: Jan-Mar

Title: Single Phase Induction Motor Drives for Low Power Applications   

Author Name: Karpagam, A. Nirmal Kumar , M. Suresh   

Synopsis:   

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.

Dynamic Improvement of Distributed Generators Connected To Distribution Networks Using DSTATCOM

Vol.5 No.3

Year: 2012                

Issue: Jan-Mar

Title: Dynamic Improvement of Distributed Generators Connected To Distribution Networks Using DSTATCOM   

Author Name: harshavardhan reddy poreddy, J.N. Chandra Sekhar , mareddy Padma Lalitha   

Synopsis:   

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.

 

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

Vol.5 No.3

Year: 2012                

Issue: Jan-Mar

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

Author Name: Rajanna GS, H.N. Nagaraj   

Synopsis:   

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.

 

Enhancement Of Power Transmission Capability Of Vsc-Hvdc System Using Fuzzy Controller

Vol.5 No.3

Year: 2012                

Issue: Jan-Mar

Title: Enhancement Of Power Transmission Capability Of Vsc-Hvdc System Using Fuzzy Controller   

Author Name: RAMESH MARPU, A.Jaya Laxmi , Rajanna GS   

Synopsis:   

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.

 

Implementation Of Genetic Algorithm For Optimal Multistage Electrical Distribution System Planning

Vol.5 No.2

Year: 2011

Issue: Oct-Dec

Title: Implementation Of Genetic Algorithm For Optimal Multistage Electrical Distribution System Planning   

Author Name: P. Ravi Babu, K Anish Kumar   

Synopsis:   

This paper describes a genetic algorithm approach to the optimal multistage planning of distribution networks. The authors describe a mathematical model and algorithm that they have developed and experimented with success. This paper also reveals the results of the proposed methodology on 50 bus test system.

 

 

 

   

Minimization Of Torque Ripple By Svm In Direct Torque Control Of Pmsm Drives

Vol.5 No.2

Year: 2011

Issue: Oct-Dec

Title: Minimization Of Torque Ripple By Svm In Direct Torque Control Of Pmsm Drives   

Author Name: sudhakar Ambarapu, Vijaya Kumar M   

Synopsis:   

An improved DTC scheme based on space vector modulation (SVM) for Permanent Magnet SynchronousMachine(PMSM) drives. The new scheme provides a alternative option for the improvement of DTC controlled PMSM in reducing the torque ripple. Closed-loop control of both torque and flux is developed with proportional Integral controllers. The stator voltage vector is generated through Space Vector Modulation unit. The torque and flux ripples are greatly reduced with space vector modulation technique comparing with classical switching-table based DTC scheme. The analysis of the control principle provides a guide to design the controller parameters. Modeling results present the features effectiveness of the proposed scheme.

 

 

 

   

Real-Time Designing And Modeling Of Online Monitoring Of Energy Consumption Using Gprs System

Vol.5 No.2

Year: 2011

Issue: Oct-Dec

Title: Real-Time Designing And Modeling Of Online Monitoring Of Energy Consumption Using Gprs System   

Author Name: P. Sujatha, P. Ram Kishore Kumar Reddy , Vijaya Kumar M   

Synopsis:   

With the development of technology, electrical automation is coming up as an optimal solution for monitoring and auditing of power consumptions. In conventional approach of power monitoring, manual readings and monitoring for the forecasting of load dispatching and consumption were made. In such an approach the error of processing is quite large. In this paper, automation of monitoring and load consumption using wireless GPRS based communication system is proposed. The designing and modeling of measuring and monitoring unit is also proposed. The developed system is tested for its feasibility over a real time distribution system and the results were evaluated.

 

 

 

   

Time-Frequency Domain Techniques For Identification Of Power System Transients

Vol.5 No.2

Year: 2011

Issue: Oct-Dec

Title: Time-Frequency Domain Techniques For Identification Of Power System Transients   

Author Name: Ashwani Kumar Chandel, P. Srikanth   

Synopsis: 

In the present work power system transient disturbances using Stockwell and Hartley Stockwell transforms have been identified. Stockwell transform (ST) is utilized previously for the real time prediction of the disturbance as it is able to accurately determine the sudden burst in the signal. However, in some cases the frequency resolution of ST is low. Consequently, Hartley Stockwell transform (HST) has been proposed which has a good frequency resolution. A comparison of proposed HST technique with ST considering various test cases has been carried out, which shows its efficacy.

 

 

   

A Comparative Analysis Of Pulse Width Modulation Techniques For Voltage Source Inverter Fed Induction Motor Drive

Vol.5 No.2

Year: 2011

Issue: Oct-Dec

Title: A Comparative Analysis Of Pulse Width Modulation Techniques For Voltage Source Inverter Fed Induction Motor Drive   

Author Name: R. Rajendran, N. Devarajan   

Synopsis:   

Adjustable speed drive system requires variable voltage and frequency supply which is invariably obtained form a threephase voltage source inverter. A number of pulse width modulation schemes are used to obtain variable voltage and frequency supply form an inverter. The most widely used PWM schemes for a three phase VSI are carrier based sinusoidal PWM (SPWM) and space vector PWM (SVPWM). There is an increasing trend of using space vector PWM because of their easier digital realization and better dc bus utilization. The MATLAB/SIMULINK simulation results show the superiority of the SVPWM compared to SPWM for an adjustable induction motor drive.

 

   

Performance Of Sepic Converter And Z-Converter For D.C. Motor

Vol.5 No.2

Year: 2011

Issue: Oct-Dec

Title: Performance Of Sepic Converter And Z-Converter For D.C. Motor   

Author Name: S.A. Elankurisil, S.S. Dash   

Synopsis: 

This paper presents the sepic converter and z converter performance are analyzed, sepic converter produces very high voltage for giving small Input voltage, reduce the total harmonic distortion to improve the efficiency form 89% to 95%. The matlab version 7.3 using for simulation results at constant frequency is used in UPS, high density discharge lamp fuel cell system and photovoltaic systems. Hardware is closely agree with the simulation result sepic converter is more advantages than z-converter they are high step up capability, design flexibility and distributed voltage stress can be achieved. To maintain continuous Input current and clamped voltage stress on switch.