Abstract

This paper presents a Fuzzy based Maximum Power Point Tracker for Photovoltaic Applications.  The proposed system contains an accurate PV module, PWM block, Fuzzy controller block and a power conditioner block. Fuzzy input parameters are  Temperature in °C, Irradiation Level and Wind velocity  are used to generate the optimal MPPT converter duty cycle, such that solar panel maximum power is generated under different operating conditions. The converter taken for our study is BUCK converters. For the operation planning of power systems, the prediction of power tracking is inevitable for photovoltaic systems. The simulation of the proposed system is done using the MATLAB/SIMULINK. This method gives highly accurate prediction compared with the conventional methods.

Abstract

In this paper, v/f control of Induction motor is simulated for both open loop and closed loop systems. The induction motor (IM) is fed from three phase bridge inverter which is operated with space vector modulation (SVM) Technique. Among the various modulation strategies Space Vector Modulation Technique is the efficient one because it has better spectral performance and output voltage is more closed to sinusoidal. The performance of SVM technique and Sine triangle pulse width modulation (SPWM) technique are compared for   harmonics, THD, dc bus utilization and Output voltage and observed that SVM has better performance. These techniques when applied for speed control   of Induction motor by v/f method for both open loop and closed loop systems it is observed that the induction motor performance is improved with SVM. It is also shown that with the introduction of active filter the performance of IM is further improved for both the cases.

Abstract

The use of modern power electronic equipment has changed our lives but also changed the load characteristics of modern facilities. Electronic loads have earned the name “Non-linear load” to describe the way they draw the power. The injected harmonics, reactive power burden, unbalance and excessive neutral currents cause low system efficiency and poor power factor. Harmonic contamination has become a major concern for power system specialists due to its effects on sensitive loads and on the power distribution system. Due to the finite (non zero) internal impedance of the utility source, the voltage waveform at the point of common coupling (PCC) to other loads will be distorted, which may cause them to malfunction. Various standards and guidelines have been established that specify limits on the magnitudes of harmonic currents and harmonic voltage distortion at various harmonic frequencies. These have been achieved using filtering system, which consists of passive and active filters & control. The proposed work deals with the design of Active filters to reduce the voltage/current harmonics in power supply system connected to Power Electronic Systems. Brief reviews from literature for various conventional active harmonic filters that are used in many industrial power systems are presented. A new control algorithm for shunt active filter is designed which uses less number of sensors and less number of control loops. The proposed algorithm works in continuous conduction mode. The operation, analysis and design of various Active/Hybrid filters are detailed and verified through MATLAB simulation.

Abstract

In this paper an attempt is made to develop an efficient algorithm for radial distribution system planning. The proposed algorithm gives optimal feeder configuration and the optimal size of branch conductors while satisfying the constraints such as reliability, current carrying capacity and minimum voltage limit. A generalized algorithm is developed for obtaining the optimal feeder path on maximum reliability and on minimum loss criteria. For branch conductor optimization, approximate load flow technique is incorporated in this paper. The proposed method is illustrated with a numerical example consisting of one substation, two feeders and 53 load nodes.

Abstract

Capacitor placement plays an important role in distribution system planning and operation. Optimal capacitor placement can result in system loss reduction, power factor correction, voltage profile improvement, and feeder capacity release. To achieve these benefits to the utmost extent under various operating constraints, distribution engineers are required to determine the optimal locations, types, and sizes of capacitors to be placed and control settings of switched capacitors at different load levels.

A Particle Swarm Optimization (PSO) based approach is used to achieve optimal capacitor placement in radial distribution systems. Discrete nature of capacitors and different load levels are all taken into consideration in the problem formulation. Mathematically, the capacitor placement problem is a non-linear  constraints. Most conventional optimization techniques are incapable to solve this hard combinatorial problem, whereas PSO algorithm is more suitable. The proposed solution method employs to search for optimal locations, types, and sizes of capacitors to be placed and optimal numbers of switched capacitor banks at different load levels. The proposed approach has been implemented and tested on various IEEE test system with promising results.

Abstract

This paper presents a control scheme and comprehensive analysis for the unified power flow controller (UPFC) on the basis of theory1, computer simulation and experiment. UPFC offers major potential advantages for the static and dynamic operation of transmission lines, but it brings with it major design challenges, both in the power electronics and from the perspective of the power system. In this paper a new model is proposed to study the Reactive compensation of the system when the Unified Power Flow Controller (UPFC) is located at the mid point of the 400KV line between KADAPA-MADRAS lines. The results thus obtained are compared with that of the SVC. The application of UPFC is demonstrated by considering the 400KV substation of Power Grid Corporation Of India Ltd., located at chinnakampalli near kadapa.  It is shown that the UPFC has the capability of producing higher Vars in comparison with that of the SVC.

Abstract

Electric utilities are operating in an increasingly competitive market where economic and environmental pressure limits their scope to expand transmission facilities. The optimization of transmission corridors for power transfer has become of great importance. In this regard, the FACTS technology is an attractive option for increasing system operation flexibility. New developments in high current, high-power electronics are making it possible to control electronically the power flows on the high voltage side of the network during both steady state and transient operation.

One important FACTS component is the TCSC (Thyristor Controlled Series Compensator), which allows rapid and continuous changes of the transmission line impedance. The TCSC module consists of a series capacitor bank in parallel with a Thyristor Controlled reactor (TCR). The controlling element is the bi-directional thyristor valve.

In this, the state variable is the TCSC’s firing angle. In this paper, a method is presented to find a best possible location from among the available locations for placing the TCSC in any one of the lines of a transmission system so as to improve the transmission efficiency of the line, and to improve the voltage profiles, stability and stability of the system.

Abstract

Energy demand in India has become a critical issue, because of growing population and technology developments. The world population may reach 10 billions by 2050 A.D. The conventional sources of energy are depleting and may be exhausted by the end of this century or beginning of the next century. India is one of the lowest per capita energy consumption countries in the world. It is therefore necessary to find alternative energy sources. Non-conventional energy sources are essential at this time to the Nation. Non-conventional energy such as power production using speed break needs no fuel input to generate electric power. This project involves a different mechanism in the power generation by making the vehicle to move over the speed break. This mechanism consists of rack and pinion, DC Generator, battery and inverter control. The conversion of the load on the speed break is converted in to electric energy is adopted in this mechanism. Based on our Indian highways we adopt this project because of the presence of several speed break. By implementing this project on such highways a large amount of power can be developed so that it can be used in traffic signals, highways lights etc., without any interruption in the power supply.

Abstract

Multi-phase ac motor drives are nowadays considered for various applications, due to numerous advantages that they offer when compared to their three-phase counterparts. In principle, control methods for multi-phase machines are the same as for three-phase machines. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information of the rotor speed is extracted from measured stator currents and voltages at motor terminals. Vector-controlled drives require estimating the magnitude and spatial orientation of the fundamental magnetic flux waves in the stator or in the rotor. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of a Model Reference Adaptive System (MRAS)-based sensorless control of vector controlled five-phase induction machine with current control in the stationary reference frame. A linear neural network has been then designed and trained online by means of PI controller algorithm. The RNN-MRAS-based sensorless operation of a three-phase induction machine is well established and the same principle is extended in this paper for a fivephase induction machine. Performance, obtainable with hysteresis current control, is illustrated for a number of operating conditions on the basis of simulation results. Full decoupling of rotor flux control and torque control is realised. Dynamics, achievable with a five-phase vector controlled induction machine, are shown to be essentially identical to those obtainable with a three-phase induction.

Abstract

Direct Torque Control (DTC) is quite different from vector control and has several advantages compared to vector control. This paper presents intelligent control scheme together with conventional control scheme by fuzzy logic approach, to overcome the problems with uncertainties in the structure encountered with classical model based design. To adjust the speed of the direct torque control of induction motor drive, a fuzzy state feedback controller is proposed based on the pole placement technique. Simulation studies have been carried out for different operating conditions of the drive system, the results have been presented and compared with those of the conventional method.

Abstract

Multi-phase ac motor drives are nowadays considered for various applications, due to numerous advantages that they offer when compared to their three-phase counterparts. Adjustable speed drives are invariably supplied from a voltage source inverter. Proper modelling of voltage source inverters is important in devising appropriate control algorithm. This paper develops complete model of a seven-phase voltage source inverter based on space vector approach. The leg voltages and line voltages along with phase voltages are illustrated. The Fourier analysis of output phase-to-neutral voltages, adjacent line voltages and non-adjacent line voltages is performed for fourteen-step and Pulse Width Modulation (PWM) modes of operation. The output phase-to-neutral voltage is shown to be essentially identical to those obtainable with a three-phase voltage source inverter.

Abstract

The basic structure of the UPFC consists of two voltage source inverters; one of them is connected in parallel, while the other converter is in series with the transmission line.  The main scope of this paper involves in designing the series connected branch of the converter, which provides a regulated voltage with variable phase shift with respect to the sending end voltage. A microcontroller program has been developed to provide a required phase shift so that it can control the amount and direction of transmitting power.The experimental result of single phase lab scale model have been achieved, which showed a  good agreement with simulated results obtained from simulated model developed in Mat lab software.

Abstract

This paper presents a controller based on the principle of Dual Mode in designing the load frequency controller. Case studies justify that Dual Mode based conventional controller yields more improved control performance than the commonly used Integral Controller. Open transmission access and the evolving of more socialized companies for generation, transmission and distribution affects the formulation of AGC problem to accommodate new constraints associated with territorial of the traditional AGC two area system is modified to take into account the role of AGC in open market system functionality of each company.  So the traditional AGC two-area system is modified to take into account the effect of bilateral contracts on the dynamics.  The concept of Disco Participation Matrix to simulate these bilateral contracts is introduced and reflected in the two-area block diagram. The proposed controllers are tested for a two area single reheat system with considering the practical aspect of the problem such as Deadband and Generation rate constraint (GRC).  Simulation results show that the limitations of Integral Controller can be over come by including the Dual Mode PI controller and thereby the response of frequency and tie line power can be improved substantially following a load change in any area.