Control of Chaos in Positive Output Luo Converter by means of Time Delay Feedback

Authors:Nagulapati Kiran

Abstract

Faster development in Dc to Dc converter techniques are undergoing very drastic changes due to that major advancements like low voltage, high power density in electronic industry. Chaos is a kind of quasi-stochastic behaviors of determinate nonlinear system. It is a non-linear phenomenon specifically found in all non-linear systems. The dc-dc converters exhibit a wide range of bifurcation and chaotic behavior under certain operating conditions. This paper analyses the behavior of Luo converter under current control mode. As the reference current is increased, the system becomes unstable to chaos. This is shown by means of bifurcation diagram. This is stabilized by means of time delayed feedback control method. The simulation is done using PSIM.

Index Terms

Chaos, Bifurcation, Positive Output Luo Converter,Time Delayed Feedback Control

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Control of Chaos in Positive Output Luo Converter by means of  Time Delay Feedback 

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Optimal Reactive Power Planning for Loss Reduction and Improvement of Voltage Profile Using Cuckoo Search Algorithm

Authors: K.R.VADIVELU , G.V. MARUTHESWAR

Abstract

This paper proposes an application of Fast Voltage Stability Index (FVSI) to Reactive Power Planning (RPP) using Cuckoo Search Algorithm (CSA). FVSI is used to identify the weak buses for the Reactive Power Planning problem which involves process of experimental by voltage stability analysis based on the load variation. The point at which Fast Voltage Stability Index close to unity indicates the maximum possible connected load and the bus with minimum connected load is identified as the weakest bus at the point of bifurcation. The proposed approach has been used in the IEEE 30-bus system.  Results show considerable reduction in system losses and improvement of voltage stability with the use of Fast Voltage Stability Index for the Reactive Power Planning problem.

Index Terms

Power systems, Reactive Power Planning, Fast Voltage Stability Index, Differential Evolution

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Optimal Reactive Power Planning for Loss Reduction and Improvement of Voltage Profile Using Cuckoo Search Algorithm

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Simulation Design, Control and Analysis of Induction Motor based AC Chopper

Authors: Cholleti Sriram, Voraganti David, Janardhan Rao

Abstract

To use the induction motor for various applications, controlling of speed is necessary. By having different speed control techniques of induction motor, stator voltage control is the only speed control technique which it can vary the voltage keeping supply frequency as constant at the input side of the motor, it can be provided by AC Chopper. By varying the stator voltage using ON-OFF control PWM technique of AC chopper, the control of speed of an induction motor is achieved. This paper proposes a stator voltage speed control technique of induction motor based AC chopper. This paper also discusses the simulation design, control and analysis of induction motor by using electro dynamics equations with the help of Simulink/MATLAB.  

Index Terms

Stator Voltage Control, Induction Motor, AC Chopper, ON-OFF control, PID Control

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Simulation Design, Control and Analysis of Induction Motor based AC Chopper 

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An Internet Protocol Quality of Service Algorithm for the Protection of Smart Power Systems

Authors: V.ARULKUMAR , S.THANGAVEL

Abstract

The paper proposes a new concept of protection philosophy for Distribution Grids with high penetration of renewable energy. Conventional protection concepts are normally based on protection schemes that consist of definite or inverse time overcurrent relays. In future power systems, these schemes can lead to high fault clearing times, unselective tripping and massive Bus disconnections, which are not acceptable in a deregulated multi owner energy market. This work proposes an efficient intelligent communication based protection algorithm that implements different multi functional protection principles supported by blocking schemes. The real time organization of both the hardware architecture and communication infrastructure of the protection algorithm is illustrated in detail. Special emphasis is given to the network reconfiguration scenario cases and detailed simulation results of such illustrative studied cases are provided. The new protection strategy guarantees protection selectivity and provides Bus unit availability during and after the fault. The intelligent algorithm is applied on existing Distribution network and meaningful conclusions are derived. It is shown that the algorithm enables a uniform fault clearing time (in the order of 78 ms) for all the geographically dispersed circuit breaker positions. The overall combination of this setup is assumed in the MATLAB/Simulink platform and the output parameters are investigated with the existing topology.

 Index Terms

Communication based protection, DG availability, intelligent algorithm, and Utility Power Grid.

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An Internet Protocol Quality of Service Algorithm for the Protection of Smart Power Systems

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Power Quality Enhancement Using Multi-Level Cascaded H-Bridge Based D-STATCOM with IRP Theory

Authors: S.K.meeravali,  K.Chandrasekhar

Abstract

This paper presents a three-phase, five-level and seven level cascaded multilevel voltage source inverter based active filter to improve the power factor and power quality in the distribution network. Cascaded multilevel configuration of the inverter has the advantage of its simplicity and modularity over the configurations of the diode-clamped and flying capacitor multilevel inverters. Shunt compensation for medium voltage distribution systems requires higher rating for voltage source converters (VSCs). Ratings of the semiconductor devices in a VSC are always limited; therefore, for higher rated converters it is desirable to distribute the stress among the number of devices using multilevel topology.  The DSTATCOM helps to eliminate the Total Harmonics Distortion (THD) drawn from a Non-Linear Diode Rectifier Load (NLDRL).  The compensation process is based on concept of p-q theory.   The simulation of the proposed system is carried out in the MATLAB environment using Simulink and power system toolboxes.

 

Index Terms

DSTATCOM, Voltage Regulation, Power Quality, Cascaded H-Bridge, Multilevel Inverters

 

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Power Quality Enhancement Using Multi-Level  Cascaded H-Bridge Based D-STATCOM with IRP Theory 

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Modified Three-Phase Four-Wire UPQC Topology with Reduced DC-Link Voltage Rating

Authors: P.Ankineedu Prasad , N.Venkateswarlu. V.Ramesh, L.V.Narasimharao

Abstract

Active Power Filters mainly divided based on converters used, i.e. based on converter type, topology and the number of phases. Converter types are Current Source Inverter (CSI) with inductive energy storage or Voltage Source Inverter (VSI) with capacitive energy storage. The topology can be shunt, series or combination of both. The third classification is based on the number of phases, such as single phase systems, three phase systems or three phase four wire systems. Criterion for selection of dc link capacitor and interfacing filter design are also discussed.

Index Terms

UPQC,VSI,FACTS, Stastcom

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Modified Three-Phase Four-Wire UPQC Topology with Reduced DC-Link Voltage Rating

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Compensation of Unbalanced Sags/Swells by Single Phase Dynamic Voltage Restorer

Authors: S.Manmadha Rao, S.V.R.Lakshmi Kumari,  B.Srinivasa Rao


Abstract

Power quality is the most important aspect in the present power system environment. Among all the power quality problems most frequently occurring disturbances, affecting the quality of power are voltage sags and swells. Custom power device, Dynamic Voltage Restorer (DVR) connected in series with a goal to protect the loads from source side voltage disturbances. In this paper single phase DVR is adopted for each phase instead of using three  phase DVR to compensate unbalanced sags/swells. Programmable voltage source is used to create sags/swells with required magnitude and time period. In this paper voltage type Impedance Source Inverter (ISI) is employed to compensate deep voltage sags/swells. DVR’s employed as series compensators in IPFC scheme to compensate voltage disturbances in individual feeders. Comparative study between PI and Fuzzy controllers is done. The project is carried out in Matlab/Simulink software.

 

Index Terms

Dynamic voltage restorer (DVR), Impedance source inverter (ISI), Interline power flow controller (IPFC)

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Compensation of Unbalanced Sags/Swells by Single Phase Dynamic Voltage Restorer

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Optimal Sizing and Placement of DG in a Radial Distribution Network using Sensitivity based Methods

Authors: Nitin Singh, Smarajit Ghosh, Krishna Murari

Abstract

In recent years, the power industry has experienced significant changes on the power distribution systems primarily due to the implementation of smart-grid technology and the incremental implementation of distributed generation. The distribution power system is generally designed for radial power flow, but with the introduction of DG, power flow becomes bidirectional. Whether the impact of the DG is positive or negative on the system will depend on the location and size of the DG. This paper focuses on testing various indices and using effective techniques for the optimal placement and sizing of the DG unit by minimizing power losses and voltage deviation. A 33-bus radial distribution system has been taken as the test system. The feasibility of the work lies on the fast execution of the programs as it would be equipped with the real time operation of the distribution system and it is seen that execution of the DG placement is quite fast and feasible with the optimization techniques used in this work.

Index Terms

Distribution Network, Distributed Generation, Load flow, Loss Sensitivity Analysis, Voltage Sensitivity Analysis

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Optimal Sizing and Placement of DG in a Radial Distribution Network using Sensitivity based Methods

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Performance and Analysis of Direct Torque Control Induction Motor FED PWM Inverter Drives

Authors: Khadim Moin Siddiqui, Kuldeep Sahay, V.K.Giri


Abstract

AC asynchronous electrical motors especially squirrel cage induction motor presents the greater advantages on cost and energy efficiency as compared with other industrial solutions for varying speed applications. The force-commutated power electronics switches (GTOs, MOSFETs, and IGBTs etc) based inverters are widely employed these days in the conversion of constant speed into variable speed induction motors. Due to the invention of these advanced power electronics switches (GTOs, MOSFETs, IGBTs etc) with improved characteristics, the PWM inverter fed induction motors are widely replacing DC motors and thyrister bridges day by day in the industries. The torque control or field control method may be used with PWM inverter fed induction motors jointly and can achieve the same flexibility in speed and torque control as with DC motors. In this present paper, an IGBT inverter fed squirrel cage induction motor with torque control technique is developed and simulated in the recent MATLAB/Simulink environment and observed the transient characteristics of the used motor. Many motor parameters have been used for induction motor analysis purpose. Further, V/f control and Total Harmonics Distortion (THD) analysis has also been carried out. Though, the stator current parameter of the motor has been widely used from last three decades with Motor Current Signature Analysis (MCSA) technique. Therefore, in the THD analysis, only stator current motor parameter has been analysed.

Index Terms

Squirrel cage induction motor (SCIM), Induction Motor (IM), Pulse width modulation (PWM), Insulated Gate Bipolar Transistor (IGBT), Time Domain Analysis, Direct Torque Control (DTC), V/f Control, MATLAB/Simulink

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Performance and Analysis of Direct Torque Control Induction Motor FED PWM Inverter Drives

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An Effective Technique for Load-Flow Solution of Radial Distribution Networks

Authors: Krishna Murari ,Smarajit Ghosh, Nitin Singh


Abstract

A new method has been developed for load-flow solution of radial distribution systems using matrix method.  The motive of this paper is to propose a technique to identify the nodes beyond each branch with less computational time. The formulated equations have been solved using matrix method. In order to find branch current, node voltage and power loss in the radial distribution network matrix method has been used. Efficacy of this method has been implemented on 33- bus radial distribution systems with constant power (CP), constant current (CC), constant impedance (CZ)  composite and exponential load modelling. The suggested method converges well for constant power, constant current, constant impedance, composite and exponential load modeling. The advantages of proposed method have compared with several existing methods in terms of relative value CPU time and memory size. The proposed method requires much less time to converge and also require less memory size when compared with the several existing methods.

Index Terms

Constant Power Load, Distribution system, Load flow, Load Flow Equations, Radial Distribution systems

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An Effective Technique for Load-Flow Solution of Radial Distribution Networks

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