Tuesday, April 7, 2009

Direct Torque Controlled Induction Motor Drive 2

DIRECT TORQUE CONTROL FOR INDUCTION MOTOR
USING INTELLIGENT TECHNIQUES
ABSTRACT
In this paper, we propose two approach intelligent techniques
of improvement of Direct Torque Control (DTC) of Induction
motor such as fuzzy logic (FL) and artificial neural network (ANN),
applied in switching select voltage vector .The comparison with
conventional direct torque control (DTC), show that the use of
the DTC_FL and DTC_ANN, reduced the torque, stator flux,
and current ripples. The validity of the proposed methods is
confirmed by the simulative results.


Basic direct torque control scheme based ANN
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New Direct Torque Control Scheme of Induction Motor
for Electric Vehicles
Abstract
In this paper, new scheme of direct torque
control of induction motor for electric vehicles is
proposed and the results of an investigation into
suitable torque control schemes are also presented.
The electric vehicle drive consists of rewound
induction motors and a three-level IGBT inverter.
The schemes investigated are Field Oriented Control,
Direct Torque Control (DTC), and DTC using Space
Vector Modulation. The results of Matlab-Simulink
simulations and a comparison between the control
schemes are presented. It is found that the DTC using
Space Vector Modulation scheme is best for this
application.



Circuit Diagram of Space Vector Modulation
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EXPERIMENTAL APPROACH OF DIRECT TORQUE
CONTROL METHOD USING MATRIX CONVERTER
FED INDUCTION MOTOR
ABSTRACT
This paper presents a study on direct torque control method
(DTC) using matrix converter fed induction motor. The
advantages of matrix converters are combined with the advantages
of the DTC technique: under the constraint of unity input power
factor, the required voltage vectors are generated to implement
the conventional DTC method of induction motor. However, since
the first idea about DTC method using MC fed induction motor was
suggested by [1], the current researches just focus on some
simulation results and a little un-explicit experimental result is carried
out. This paper describes the operation of induction motor under the
DTC method in steady-state and transient conditions by the
experimental results, the discussion about the trend of DTC method
using MC is also carried out. Furthermore, the entire system of
matrix converter configuration using 7.5kW IGBT modules
(FR35R12KE3V1) is explained in detail.
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DIRECT TORQUE CONTROL STRATEGY OF
INDUCTION MOTORS

Direct Torque Control of inverter-fed Induction Machine allows
high dynamic performance by means of very simple
control schemes. In this paper various direct torque control
methodologies as conventional DTC (C_DTC), modified DTC
(M_DTC) and twelve sectors (12_DTC) have been analysed
and compared in order to evaluate the influence of the motor
operating condition on steady state performances. A particula
r emphasis on stator flux trajectory, torque ripple and stator
current distortion has been made. Simulation results show the
effectiveness of the proposed methods.
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Direct Torque Control of Induction Motors
D.C. motors have been used widely during the last
century in applications where variable-speed
operation was needed, because its flux and torque can
be controlled easily by means of changing the field
and the armature currents respectively. Furthermore,
operation in the four quadrants of the torque-speed
plane including temporary standstill was achieved.
However, DC motors have basically two drawbacks,
which are the existence of commutators and brushes.
These two disadvantages implied not only periodic
maintenance but also difficulty to work in dirty and
explosive environments; difficulty that sometimes
used to become in impossibility.
On the other hand, induction motors