Direct Torque Control with Space Vector Modulation (DTC-SVM) of ...
Direct Torque Control with Space Vector Modulation (DTC-SVM) of ...
Direct Torque Control with Space Vector Modulation (DTC-SVM) of ...
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<strong>Direct</strong> <strong>Torque</strong> <strong>Control</strong> <strong>with</strong> <strong>Space</strong> <strong>Vector</strong> <strong>Modulation</strong><br />
Ωm<br />
1 1<br />
GΩ<br />
() s = = = (5.83)<br />
M Js Js<br />
e<br />
Continuous s-domain<br />
The block diagram <strong>of</strong> speed control loop is shown in Fig. 5.47, where CΩ ( s)<br />
is a<br />
transfer function <strong>of</strong> the PI speed controller given by:<br />
KiΩ<br />
KpΩ( s+<br />
)<br />
1<br />
K<br />
pΩ<br />
CΩ() s = KpΩ(1 + ) = (5.84)<br />
T s s<br />
iΩ<br />
and DΩ ( s)<br />
is approximated transfer function <strong>of</strong> closed torque control loop for cascade<br />
or parallel <strong>DTC</strong>-<strong>SVM</strong> structure.<br />
M L<br />
Ω m _ ref<br />
M e ref<br />
_<br />
CΩ () s<br />
D () s<br />
G () s<br />
Ω<br />
M e<br />
Ω<br />
Ω m<br />
Figure 5.47. Block diagram <strong>of</strong> speed control loop in s-domain.<br />
Discrete design<br />
The transfer function for PI controller in discrete system using backward difference<br />
method for discretization process is expressed as:<br />
K<br />
pΩ<br />
( z − )<br />
KpΩ<br />
+ KiΩ<br />
CΩ( z) = ( KpΩ + KiΩ)<br />
(5.85)<br />
( z −1)<br />
K<br />
pΩ<br />
Where: KiΩ<br />
= Ts- integration and K<br />
p Ω<br />
proportional gain <strong>of</strong> speed controller, T s<br />
-<br />
T<br />
sampling time.<br />
iΩ<br />
111