Direct Torque Control with Space Vector Modulation (DTC-SVM) of ...

Direct Torque Control with Space Vector Modulation
5.4 Speed control loop for DTC-SVM structure
The structure of speed control loop for cascade (a) and parallel (b) DTC-SVM scheme
is shown in the Fig. 5.46.
a)
U DC
Ψ s _ ref
U
s α _ ref
S A
S B
Ω m _ ref
M e _ ref
e M
∆δ Ψ
U
s β _ ref
S C
θ Ψs Ψs
I s
M e
I s
d
dt
γ m
U DC
b)
Ψ s _ ref
e Ψ
ss
U sx _ ref
s
_ ref
S A
S B
Ω m _ ref
M e _ ref
e M
U sy _ ref
U α
U
s β _ ref
S C
θ Ψs
Ψ
I s
M e
d
dt
Figure 5.46. Speed control loop for: a) cascade structure of DTC-SVM scheme, b) parallel
structure of DTC-SVM scheme.
γ
m
The mechanical speed equation (2.66) for the PMSM is:
dΩ
M M J dt
m
e
−
L
= (5.81)
Taking Laplace transformation to equation (5.81) one obtains:
M () s − M () s = JsΩ () s
(5.82)
e L m
The transfer function between mechanical rotor speed
M
e
can be expressed as:
Ω
m
and electromagnetic torque
110