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

Direct Torque Control with Space Vector Modulation
K
pΨ
C
A
Ψd
Ψd
= = (5.19)
Ψd
C
T
s
For example let us assume that sampling time in digital flux control loop is equal T = 200µ
s.
The gain of P controller is:
s
K
pΨ
0.2688 0.2688
= = = 1344
(5.20)
A 0.0002
Ψd
In digital control when the sampling time changes the parameters of digitalized plant control
A Ψ d
will also change. Therefore, to keep closed loop transfer function as close as possible to
G
C
0.2688
( z)
= =
, the gain of P flux controller should also be
z − z+ C z −z+ 0.2688
Ψd
Ψ _ closed
2 2
Ψd
changed (see Table 5.1.).
Keeping constant transfer function GΨ _ closed
( z)
the flux step response for different sampling
times
T
s
= 50µ s , 100µ s , 200µ s , 400µ s , which correspond to switching frequency f s
=
20kHz, 10kHz, 5kHz, 2.5kHz are presented in Fig. 5.11.
Figure 5.11. Flux tracking performance for different sampling times T
s
= 50µ s (blue line -1), 100µ
s
(green line -2), 200µ s (red line -3), 400µ s (light blue line -4).
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