Simulation and Transient Analysis of PWM Inverter Fed Squirrel Cage Induction Motor Drives

Vol.7  No.3

Year : 2014

Issue : Jan-Mar

Title : Simulation and Transient Analysis of PWM Inverter Fed Squirrel Cage Induction Motor Drives

Author Name : Khadim Siddiqui, Kuldeep Sahay , V.K. Giri

Synopsis :

Squirrel Cage Induction Motors are the widely used motors in Industries due to its simple construction, robust design and low operational costs. The utilization of Squirrel Cage Induction Motors with electronic inverters present greater advantages on cost and energy efficiency, compared with other industrial solutions for varying speed applications. The induction motor with inverters gives excellent speed torque control characteristics. In this paper, a transient behavior of a 3HP, 4 Pole, 50 Hz, 1430 rpm Squirrel Cage Induction Motor has been analyzed. The open and closed loop induction motor is fed Into Pulse Width modulation (PWM) inverter model developed in the recent Matlab/Simulink environment. The Sinusoidal Pulse Width Modulation (SPWM) variable speed drives are increasing these days and used in various industrial applications with superior performance. Since the developments in power electronics and semiconductor technology have led to improvements in power electronic systems, consequently variable voltage and variable frequency control is obtained by Voltage Source Inverters (VSC). In Induction motor drives, SPWM inverters make it possible to control both frequency and magnitude of the voltage and current applied to the motor. As a result, PWM inverter- powered motor drives are more variable and offer in a wide range better efficiency and higher performance when compared to the fixed frequency motor drives. These inverter fed-motors are recently gathering great popularity for multi-megawatt industrial drive applications. In this present paper, the open and closed loop induction motor fed with PWM inverter model has been discussed and focused on transient characteristics of the motor. The direct torque control method is used to control the induction motor in closed loop.

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Cascaded Operation of Buck Converter

Vol.7  No.3

Year : 2014

Issue : Jan-Mar

Title : Cascaded Operation of Buck Converter

Author Name : Prema Latha, Murugesan. P

Synopsis :

This paper deals with the simulation of Cascaded Interleaved Buck Converter (IBC) with open source operation having low switching losses, less ripple and improved step-down conversion ratio, which is suitable for the application where the input voltage is high. A series of active switches with coupling capacitor are employed in the power circuit. This paper deals with Cuk, Sepic and Zeta converters. All active switches are only stressed with half of the input voltage before turning on or after turning off the proposed IBC. The capacitive discharging and switching losses can be reduced considerably to have higher efficiency, higher step-down conversion ratio, higher switching frequency and a smaller output ripple compared with a conventional IBC. The model of cascaded Interleaved buck converter system are presented.

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A Modified Unbalanced Load flow solution using Branch Incidence Matrix

Vol.7  No.3

Year : 2014

Issue : Jan-Mar

Title : A Modified Unbalanced Load flow solution using Branch Incidence Matrix

Author Name : Dr. N Visali, M Satish kumar reddy, SURENDRANATHA REDDY M

Synopsis :

Distribution system is the system which supplies electrical power from generating station to consumers. But the practical loads in the radial distribution systems are generally unbalanced in nature. For analysing the system condition and also to forecast the load, the study of power flows is essential. The presence of high R/X ratio of the distribution system poses a challenge to the convergence criteria of commercial load flows such as Newton Raphson Method, Gauss Seidel method and Fast Decoupled methods. For this type of systems, some changes have been incorporated in above methods so as to obtain better convergence which are named as modified Newton Raphson Method, modified Gauss Seidel Method and Forward/Backward Sweep Methods. The pre-assumption of flat node voltage is essential to carry out the load flow solution in all these methods. A new method has been proposed to determine the solution without any preassumptive flat node voltage and also the unbalanced system is modelled as a balanced system using symmetrical components. The solution is obtained by incorporating relationship between node currents and branch currents using a concept of Branch Incidence matrix and thereby eliminating the need for flat voltage profile. The proposed method has been presented in three sections. In First section 1 the formation of the branch incidence matrix by modelling of unbalanced Radial Distribution System comprising of transformers, switches, capacitors etc. using symmetrical components, In section 2 node voltages and power losses are calculated using branch incidence matrix and system parameters. Finally in section 3, the results obtained are compared with the existing methods. The proposed method is solved for three different unbalanced Radial Distribution Systems such as IEEE 13 node, 19 node and 25 node systems and the results are presented.

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Sensorless Speed Control of Permanent Magnet Linear Synchronous Motor using Extended Kalman Filter

Vol.7  No.3

Year : 2014

Issue : Jan-Mar

Title : Sensorless Speed Control of Permanent Magnet Linear Synchronous Motor using Extended Kalman Filter

Author Name : B Arundhati, K. Alicemary , S.Koteswar Rao , Thota.Raghavendra

Synopsis :

This paper proposes the Sensorless Speed Control of Permanent Magnet Linear Synchronous Motor (PMLSM) using Extended Kalman Filter (EKF). Linear Speed and position of PMLSM is estimated using EKF. The mathematical model for PMLSM & EKF is established. The simulation model for sensor and sensor-less speed control of PMLSM using EKF is constructed using MATLAB/ SIMULINK. The linear motor speed and position are compared for both sensor and sensorless using EKF. It is observed that the estimated speed and position values are almost similar to actual values. Though it has disadvantages such as complex algorithm and larger matrix operations, sensorless speed control eliminates the requirement of mechanical sensor and hence reduces the drive cost and enhances reliability.

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Importance of Energy Conservation, Energy Management and their Opportunities

Vol.7  No.3

Year : 2014

Issue : Jan-Mar

Title : Importance of Energy Conservation, Energy Management and their Opportunities

Author Name : Shekhappa Ankaliki

Synopsis :

This article presents the different sources of energy, importance of energy conservation, energy management and their opportunities available at utility and customer side in the present day scenario. The article has discussed the environment, economics, sustainable development, energy independence, green fuels, clean energy, energy conversion and safety in electrical engineering.

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Modeling, Control and Implementation of Dc-Dc Converters for Variable Frequency Operation

Vol.7  No.2

Year : 2013

Issue : Oct-Dec

Title : Modeling, Control and Implementation of Dc-Dc Converters for Variable Frequency Operation

Author Name : Shailaja Rout, Pradosh Ranjan Parida , Dr. Chinmoy Kumar Panigrahi , Dr M.Basu

Synopsis :

In this work the authors propose a novel approach in modelling and controller design of the synchronous dc-dc step down converters. Power electronic converters are mainly periodic variable systems due to their variable switched systems. The generalized or enhanced the state space averaging is a better approach than the state space averaging as it defines them by a unified set of differential equations, capable of representing circuit waveforms. This model is then used to design a PID controller which will help us in understanding the converter dynamics.

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Power Quality improvement using D-Statcom

Vol.7  No.2

Year : 2013

Issue : Oct-Dec

Title : Power Quality improvement using D-Statcom

Author Name : P. Venkata Kishore, Rama Reddy

Synopsis :

The D-STATCOM is a shunt connected FACTS device which supplies reactive power to the load to improve the voltage stability of the load buses. The D-STAT COM in multi bus system is capable of reducing the losses and improving the voltage regulation. This work deals with the comparison of Push Pull and Voltage Inverter based D-STATCOM for multi bus system. Eight bus system is modeled using the elements of SIMULINK. The models are developed for eight bus systems with and without D-STATCOM. The two D-STATCOM systems are compared with respect to total harmonic distortion and reactive power comparison. The D-STATCOM is studied with respect of the voltage stability improvement at the load buses. The results of VSI based D-STATCOM system are compared with those of Push pull inverter based D-STATCOM system.

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Optimal Selection of Capacitors for Radial Distribution Systems to improve Annual Cost Savings & Loss Minimization using Optimization Techniques in Mat Lab Environment

Vol.7  No.2

Year : 2013

Issue : Oct-Dec

Title : Optimal Selection of Capacitors for Radial Distribution Systems to improve Annual Cost Savings & Loss Minimization using Optimization Techniques in Mat Lab Environment

Author Name : SURENDRANATHA REDDY M, M Satish kumar reddy

Synopsis :

The problem of voltage deviation and power loss is mostly addressed in distribution system by growing domestic, industrial and commercial load day by day. To minimize these problems, effective planning of distribution system is required. This effective and reliable planning of distribution system is achieved by optimized placement of control device (capacitor) in distribution networks. The idea for optimal capacitor placement is determined that location of the capacitor is to be installed in the distribution network buses where power losses should be minimum and cost saving should be maximum. This paper presents a new and efficient approach for capacitor placement in radial distribution systems that determine the optimal locations and size of capacitor with an objective of improving the annual cost saving, the voltage profile and reduction of power loss. The solution methodology includes an algorithm that employs Plant Growth Simulation Algorithm (PGSA) and Genetic algorithm to estimate the optimal size of the capacitors at the optimal buses determined. The effectiveness of the proposed method is applied to 33 and 69 bus IEEE radial distribution systems. Result shows that after placement of capacitor in candidate buses the energy loss has been reduced.

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Real Time Implementation of Speed Control of PMLSM with Space Vector Pulse Width Modulation using dSPACE

Vol.7  No.2

Year : 2013

Issue : Oct-Dec

Title : Real Time Implementation of Speed Control of PMLSM with Space Vector Pulse Width Modulation using dSPACE

Author Name : B Arundhati, K. Alicemary , Suryakalavathi , K. Shankar

Synopsis :

This paper proposes speed control of permanent magnet linear synchronous motor using Space Vector Pulse Width Modulation (SVPWM). Among the various modulation strategies Space Vector Modulation Technique is the efficient one because of its better spectral performance, better dc bus utilization and easier digital realization. With SVPWM the performance of PMLSM is improved because it eliminates all the lower order harmonics in the output voltage of the inverter when compared to the conventional SPWM technique. The open loop & closed loop simulation model for SVPWM with PMLSM is constructed using MATLAB/SIMULINK. Hardware is implemented and validated Using dSPACE ds1104 controller board.

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Comparison of Advanced State Estimation Techniques for Optimal Placement Solution of Pmu's in Interconnected Power Networks

Vol.7  No.2

Year : 2013

Issue : Oct-Dec

Title : Comparison of Advanced State Estimation Techniques for Optimal Placement Solution of Pmu's in Interconnected Power Networks

Author Name : Naveen Kumar, Suryakalavathi

Synopsis :

Monitoring and supervision is an important aspect in view of security of an interconnected power system. The work presented here gives a comparison of various advanced state estimation techniques for optimal placement of Phasor Measurement Units in Power Networks. These techniques meet two requirements i.e. to ensure the complete system observability and at the same time find the optimal locations of Phasor Measurement Units with the minimum cost. The problem is formulated as a mono-objective optimization problem and its resolution is made by implementing seven algorithms which are mentioned in this paper. The proposed algorithms are demonstrated using five test networks that include a practical system. The simulation results ensure the complete system observability.

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