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

Direct Torque Control with Space Vector Modulation
Dz ( )
G ( ) M
z
M
e_ ref( z)
P ( ) M
z
C ( ) M
z
∆δ Ψ
G
Mδ
( z)
U s
z −1
AM
s
ZOH
2
s + B s+
C
M
M
M ( ) e
z
Figure 5.19. Block diagram of torque control loop with prefilter (discrete domain).
Finally, the step response of closed torque control loop with prefilter at the input is
presented bellow:
a) b)
Figure 5.20. a) Torque step response for sampling time T = 200µ
s, b) with denoted rise time,
overshoot and settling time.
s
As it can be observed, the response is now characterized by overshoot about 2%, rise
time 5 samples and the settling time 15 samples.
In digital control system when the sampling time is changed the parameters of
digitalized control plant AMd, BMd,
C
Md
will also change. Therefore, the parameters of PI
torque controller will change also (see Table 2).
Simulation results for digital torque control loop in SABER package for 5KHz with and
without prefilter are shown in Fig. 5.21. Also, the torque step response for different
level of reference torque are presented in Fig. 5.22.
The settings for PI torque controller for different sampling time T s
= 50µ s , 100µ s ,
200µ s , 400µ s are summarized in Table 5.2.
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