Now
a day’s induction motor
drives are highly demanding to design both mechanical and electrical drive
system which is used widely in many industrial applications. Recent years many
mathematical models for induction motor drive using Simulink models are
employed. Scalar and Vector control method can be applied to induction motors
in three phases symmetric as well as unsymmetrical two-phase form. The mathematical
and Simulink operation of the induction motor drive can be studied and it is
equivalent to a DC motor by the vector control method. With the combined
performance of the numerical electronics and power electronics we are capable
to smoothly control the variable speed and torque in low power industrial
operations. With the help of technological achievements, several command and
control techniques are developed by the technologists to control the time, flux
and torque of the industrial electrical machine drives. The direct torque
control (DTC) technique is one of the most advanced mechanisms in control
operation of torque and speed. This technique with SVPWM gives fine regulation without
rotational speed controlled feedback. The electromagnetic torque and stator
flux are estimated in DTC technique only stator currents and voltage and it is independent
of the parameters of the motor except for the Rs i.e. stator resistance [7].
KEYWORDS:
1. Controller
2. DTC
3. IDM
4. SVPWM
and switching table.
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.1.
DTC block diagram
Fig.2.
Electromagnetic torque
Fig.3.
Rotor speed
Fig.4.
Stator current
Fig.5.
d-axis stator flux
Fig.6.
q-axis stator flux
Fig.7.
Electromagnetic torque
Fig.8.
Rotor speed
Fig.9.
Trajectory of direct axis stator and quadrature axis
flux
(stationary reference frame)
Fig.10.
Electromagnetic torque
Fig.11.
Rotor speed
Fig.12.
Direct axis stator flux
Fig.13.
Quadrature axis stator flux
Fig.14.
Direct axis stator current
Fig.15.
Quadrature axis stator current
Fig.16.
Stator flux trajectory
Fig.17.
Rotor flux trajectory
CONCLUSION:
The
proposed paper highlights to create a Simulink model of DTC in induction motor drive. The DTC
technique allows the decoupled control of torque and stator flux operate indipendently.
The control process is simulated with the help of simpower system MATLAB
Simulink block set and Sector determination with open-loop induction motor
drive is obtained. In conventional DTC technique, high torque ripple is
produced because the voltage space vector which are considered is applied for
the whole switching period without considering the torque error value. This
torque ripple can be minimized in order to achieve a smooth operation of the
drive system and its performances, by changing the duty cycle ratio of the
voltage vector which are selected during each switching cycle period, based on
the stator flux position and torque error magnitude. This constitutes the basic
of SVPWM technique. here simulate DTC scheme based on SVPWM technique and
comparative study of conventional DTC-SVM scheme is derived and studied.
REFERENCES:
[1]
Takahashi Isao, Noguchi Toshihiko, ,,’’A New Quick-Response IEEE Transactions
on Industry Applications , Vol. IA-22No-5, Sept/Oct 1986.
