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 />
• increment <strong>of</strong> torque angle ∆δ Ψ<br />
coming from torque control loop (see Fig.5.2.) is equal<br />
zero. It means that the torque is not produced,<br />
• stator flux vector position θ Ψ s<br />
and rotor flux vector position θ r<br />
are equal zero. It<br />
corresponds to situation, where the those two flux vectors lie along the α axis.<br />
In this special case the reference stator flux amplitude Ψ<br />
_<br />
=Ψ<br />
α _<br />
can be controlled<br />
s ref s ref<br />
trough the reference stator voltage component U<br />
α _<br />
= U<br />
_<br />
, when the voltage drop on the<br />
s ref s ref<br />
stator resistances in α,<br />
β axes are neglected (see Fig. 5.5). Therefore, the simplified flux<br />
control loop can be shown in Fig. 5.6.<br />
Ψ =Ψ α<br />
s _ ref s _ ref<br />
s sα<br />
Ψ =Ψ<br />
−<br />
∆Ψ sα<br />
controller<br />
P<br />
U<br />
sα _ ref<br />
= Us _ ref<br />
U β<br />
=<br />
s _ ref<br />
0<br />
PMSM<br />
Ψ sα<br />
Ψ sβ<br />
Continuous s-domain<br />
Figure 5.6. Simplified flux control loop in α,<br />
β coordinates.<br />
Simplified flux control loop in s domain is shown in Fig. 5.7, where CΨ ( s)<br />
is a transfer<br />
function <strong>of</strong> the P controller given by:<br />
CΨ() s = KpΨ<br />
(5.11)<br />
The transfer function between stator flux amplitude Ψ<br />
s<br />
=Ψ sα and stator voltage amplitude<br />
U<br />
s<br />
can be expressed as:<br />
G<br />
Ψ<br />
Ψ<br />
s 1<br />
() s = = (5.12)<br />
U s<br />
s<br />
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