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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Sensorless Speed <strong>Direct</strong> <strong>Torque</strong> <strong>Control</strong> <strong>with</strong> <strong>Space</strong> <strong>Vector</strong> <strong>Modulation</strong> (<strong>DTC</strong>-<strong>SVM</strong>)<br />
Is<br />
α<br />
Is<br />
β<br />
U<br />
s α<br />
Ψ<br />
sα<br />
Ψ sβ<br />
Ω =<br />
Ψs<br />
d<br />
dt<br />
θ Ψ s<br />
dδ Ψ<br />
dt<br />
−<br />
1<br />
p b<br />
Ω m<br />
U<br />
s β<br />
Figure 6.12. Block diagram <strong>of</strong> stator flux vector based rotor speed estimator.<br />
The synchronous speed<br />
Ω<br />
Ψs<br />
is calculated based on the stator flux estimator:<br />
θ Ψ s<br />
Ψ<br />
sβ<br />
= arctg( )<br />
Ψ<br />
sα<br />
(6.22)<br />
and the calculation <strong>of</strong><br />
ΩΨs<br />
can be done as:<br />
The estimation <strong>of</strong> the synchronous speed<br />
dθ θ<br />
s Ψs( k) −θ<br />
Ψ<br />
Ψs( k−1)<br />
Ω<br />
Ψs<br />
= = (6.23)<br />
dt T<br />
s<br />
Ω<br />
Ψs<br />
based on the derivative <strong>of</strong> the position <strong>of</strong><br />
stator flux space vector can be modified taking in to account equation (6.22), which<br />
finally gives [12]:<br />
Ψ<br />
Ω =<br />
Ψs<br />
sα<br />
dΨ<br />
sβ<br />
−Ψ<br />
dt<br />
Ψ +Ψ<br />
sβ<br />
2 2<br />
sα<br />
sβ<br />
dΨ<br />
dt<br />
sα<br />
(6.24)<br />
Digital implementation <strong>of</strong> equation (6.24) can be written as:<br />
Ψ Ψ −Ψ Ψ<br />
Ω =<br />
Ψ T<br />
sα( k−1) sβ( k) sβ( k−1) sα( k)<br />
Ψs( k) 2<br />
s<br />
s<br />
(6.25)<br />
Also from equation (2.27b) in stator flux coordinate system the synchronous speed<br />
can be obtained as:<br />
Ω<br />
Ψs<br />
U − R I E<br />
Ω<br />
Ψs<br />
= =<br />
Ψ Ψ<br />
sy s sy sy<br />
s<br />
s<br />
(6.26)<br />
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