Direct Torque Control Based on Space Vector Modulation with Adaptive
Stator Flux Observer for Induction Motors
ABSTRACT:
This
paper describes a combination of direct torque control (DTC) and space vector
modulation (SVM) for an adjustable speed sensor less induction motor (IM)
drive. The motor drive is supplied by a two-level SVPWM inverter. Using the IM
model in the stator – axes reference frame with stator current and flux vectors
components as state variables. In this paper, a conventional PI controller is
designed accordingly for DTC-SVM system. Moreover, a robust full-order adaptive
stator flux observer is designed for a speed sensor less DTC-SVM system and a
new speed adaptive law is given. By designing the observer gain matrix based on
state feedback control theory, the stability and robustness of the observer
systems is ensured. Finally, the effectiveness and validity of the proposed
control approach is verified by simulation results.
KEYWORDS:
1.
DTC
2.
Stator Flux Observer
3.
Torque Ripple
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1
Block Diagram of DTC-SVM system
CONCLUSION:
A
novel DTC-SVM scheme has been developed for the IM drive system, In this
control method, a SVPWM inverter is used to feed the motor, the stator voltage
vector is obtained to fully compensate the stator flux and torque errors.
Furthermore, a robust full-order adaptive flux observer is designed for a speed
sensor-less DTC-SVM system. The stator flux and speed are estimated synchronously.
By designing the constant observer gain matrix, the robustness and based on
state feedback stability of the observer systems is ensured. Therefore, the
proposed sensor-less drive system is capable of steadily working in very low
speed, has much smaller torque ripple and exhibits good dynamic and
steady-state performance.
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[2] Y. S. Lai and
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[5]
A. Arias, J. L. Romeral, and E. Aldabas, “Fuzzy logic direct torquecontrol,” in
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