Conventional Method And Space Vector Pulse Width Modulation Technique For Ripple Reduction

3279 Words Nov 13th, 2014 14 Pages
Direct Torque Control of Induction Motor Simulation using Conventional Method And Space Vector Pulse Width Modulation Naveen Chander
PG Student
Electrical Engineering
NITTTR
Chandigarh, India snl.naveen@gmail.com Dr. S. Chatterji
Professor & Head
Electrical Engineering
NITTTR
Chandigarh, India

Dr. Lini Mathew
Associate Professor
Electrical Engineering
NITTTR
Chandigarh, India

Abstract—This paper proposes direct torque control of induction motor simulation using conventional method and space vector pulse width modulation technique for ripple reduction. Direct Torque Control (DTC) is a control technique used in AC drive systems to obtain high performance torque control and thereby controlling the speed of induction motor. The
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Hence the scheme proves itself superior to the DC machine. The problem faced by FOC scheme is complexity in its implementation due to dependence of machine parameters, reference frame transformation. Later DTC was introduced. Direct torque control (DTC) method is used to control the torque (finally speed) in variable frequency drives of three-phase AC electric motors. From the measured voltage and current of the motor an estimate of the motor 's magnetic flux and torque is calculated. Integrating the stator voltages, stator flux linkage is estimated. Cross product of measured motor current vector and estimated stator flux linkage vector results in estimated torque. The estimated flux magnitude and torque are then compared with their reference values. If either the estimated flux or torque deviates from the reference more than allowed limits, the transistors of the variable frequency drive are turned OFF and ON in such a way that the flux and torque errors will return in their tolerant bands as fast as possible. Thus direct torque control is one form of the hysteresis control. The method requires only the stator resistance to estimate the stator flux and torque.
The basic DTC scheme [1] consists of two comparators with specified bandwidth, switching table, voltage source inverter, flux and torque estimation block. Like every control method has some advantages and disadvantages, DTC method has too. Some of the advantages are lower parameters dependency, making
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