11-05-2013, 03:28 PM
Design of Direct Torque Controller of Induction Motor (DTC)
Design of Direct.pdf (Size: 388.01 KB / Downloads: 109)
Abstract
Induction motors are currently used in many industrial applications. Thus, their control techniques have
received a lot of interest. An efficient method of induction motor control is the direct torque control
(DTC). In this project, a DTC model has been developed and tested using a MATLAB/SIMULINK
package. A 6 kW three phase induction motor has been used in order to run and evaluate the developed
model. Simulation results have shown the validity and high accuracy of the proposed model. The
independence of torque and stator flux control has been confirmed. However, further work should be
done in order to limit the significant variation in the starting up stator current caused by any small
variation in the stator flux in the developed DTC model.
INTRODUCTION
Because of their robustness, cheapness, high speed operation and less maintenance requirements, the
induction motors (IM) are the most common type of electromechanical drive in industrial, commercial and
residential applications. To reach the best efficiency of induction motor drive (IMD), many new techniques of
control have been developed in the last few years.
DTC BLOCK DIAGRAM
DTC was introduced by Takahashi (1984) in Japan and then in Germany by Depenbrock (1985) [4]. Unlike
the traditional vector control, DTC doesn’t require coordinate transformation, PI regulators, PWM and position
encoders. Hence, DTC is much simpler. Moreover, Both DTC and VC provide good dynamic response but DTC
is less sensitive to the motor parameter variations [5].
DTC Block diagram is shown in Fig.7.Basically, both torque and stator flux need to be estimated so that they
can be directly controlled in a way that keeps them within a hysteresis band close to the desired values. This is
achieved by choosing the appropriate sector in space vector modulation which will be described in section X.
According to [6], the torque produced by a