Performance and Analysis of Switching Function Based Voltage Source Inverter Fed Induction Motor

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


Abstract

In industries, the three phase squirrel cage induction motor is widely used due to its simple construction, robust design and low operational costs. The exploitation of squirrel cage induction motor with power semiconductor devices based inverters presents the greater advantages on cost and energy efficiency, compared with other industrial solutions for varying speed applications.  Since, Inverter fed-induction motors are gathering great attractiveness for multi-megawatt industrial drive applications these days. In the present paper, an extensive simulation has been carried out for open and closed loop models of 3HP, 50 Hz, 1430 RPM switching function based voltage source inverter fed into induction motor.  The transient analysis has been carried out by both models. The analysis has been carried out in the recent MATLAB/Simluink environment. The open and closed loop models give encouraging results and observed that the closed loop model gives better results as compared to open loop model with reduced harmonics. Six motor signatures are used for analysis purpose; these are stator current, rotor current, rotor speed, electromagnetic torque, q-axis rotor flux and q- axis stator flux respectively. Though, it has been seen that the stator current parameter has been widely used parameter in last two decades with Motor Current Signature Analysis (MCSA). Therefore, in the harmonic analysis only stator current parameter is used. The torque control method is used for controlling the induction motor in closed loop due to its advantages over vector or field-control method.

Index Terms

Squirrel Cage Induction Motor (SCIM), Voltage Source Inverter (VSI), Pulse Width Modulation (PWM), Direct Torque Control, Open/Closed Loop, MATLAB/Simulink.

 

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Performance and Analysis of Switching Function Based Voltage Source Inverter Fed Induction Motor

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Backward/Forward Sweep Based Distribution Load Flow Method

Authors: Sunisith and  K. Meena


Abstract

The function of an electric power system is to connect the power station to the consumer loads by means of inter connected system of transmission and distribution networks. Therefore, an electric power system consists of three principal components:  The power station, the transmission lines and the distribution system. The power flow method is a fundamental tool in application software for distribution management system. In this paper, a method to solve the distribution power flow problem has been introduced. The reason, why the convergence of these widely used methods deteriorates when the network becomes radial, is also well analyzed. Subsequently, a theoretical formulation of backward/forward sweep distribution load flow method is described. This proposed method has clear theory foundation and takes full advantage of the radial structure of distribution systems. The numerical test proved that, this method is very robust and has excellent convergence characteristics.

Index Terms

Backward/Forward Sweep, Distribution load flow method

 

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Backward/Forward Sweep Based Distribution Load Flow Method

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Methodology for Alleviation of Voltage Excursions in Large Power Systems

Authors: Sunisith, T. Manidhar and M. Rajendar


Abstract

The purpose of reactive power scheduling is to improve the voltage profile of the system. This objective is achieved by installing reactive power sources at appropriate locations in a large power network. Proper adjustment of these sources is of paramount importance in obtaining the desired goal. This paper presents a methodology for alleviation of over voltage and under voltage conditions in the day to day operation of power systems by minimizing the sum of the squares of the voltage deviations from preselected desired values. The above objective function is selected to meet the recent requirements of utilities that are paying increasing attention to the problem associated with the voltage profile in power system. To achieve the desired objective, the control variable selected are tap position of transformers, reactive power injection of VAR sources and generator excitations. The proposed algorithm is applied to IEEE 30-bus systems and the results are obtained satisfactory with the proposed approach.

Index Terms

Alleviation of Voltage Excursions, Genetic Algorithm, Reactive Power Injection

 

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Methodology for Alleviation of  Voltage Excursions in Large Power Systems

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Application of Neurofuzzy in Power System for Short Term Load Forecasting

Authors: Sunil Kumar and Kapil Dev Sharma

Abstract

 Short-term load forecasting (STLF) is a necessary daily task for power dispatch. Its accuracy affects the economic operation and reliability of the system. This paper  presents a solution methodology using fuzzy logic approach and artificial neural network for short term load forecasting and is implemented on historical weather sensitive data i.e. temperature, humidity, wind speed and historical load data for forecasting the load. The proposed fuzzy logic approach is implemented on weather sensitive data and the accuracy of the result is compared using two different membership functions. Artificial neural network approach is implemented on the proposed non-fully connected neural network consists of five fully connected supporting networks representing weather variables, day type and load data as inputs.

Index Terms

Load forecasting, Neural model, Fuzzy logic, Neurofuzzy

 

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Application of Neurofuzzy in Power System for Short Term Load Forecasting 

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Modified Clonal Selection Algorithm based Power System Stabilizers for Damping Power System Oscillations in Multi-machine Power System

Authors:  Naresh, M. Ramalinga Raju and S. V. L. Narasimham


Abstract

In this paper, a novel Modified Clonal Selection Algorithm (MCSA) has been proposed for optimal design of Conventional Power System Stabilizers (CPSS) to damp low frequency power oscillations in a multi-machine power system. Based on the process of elimination of foreign antigens by the immune cells in any biological system, this paper attempts to optimize three constants each of several Power System Stabilizers (PSS) present in New England 10-machine, 39-bus power system. A multi-objective problem has been formulated to optimize a composite set of objective functions comprising the damping factor, and the damping ratio of the lightly damped electromechanical modes. The eigenvalue analysis and nonlinear simulation results presented under a wide range of operating conditions show the effectiveness and robustness of the proposed MCSA based PSS and its ability to provide efficient damping to low frequency oscillations. Further, all these time domain simulation results have been compared with conventional and clonal selection algorithm based PSS to show the superiority of the proposed design approach.

 

Index Terms

 Damping, Modified clonal selection algorithm, Multi-objective optimization, Power system stabilizer

 

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Modified Clonal Selection Algorithm based Power System Stabilizers for Damping Power System Oscillations in Multi-machine Power System

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