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

Direct Torque Control with Space Vector Modulation
The discrete transfer function of digital filter for T = 200µ
s and f = 25Hz
can be
calculated as:
0.015466 (z+1)
FΩ ( z)
= (5.94)
(z-0.9691)
Hence, the transfer function speed control loop with digital filter:
s
c
G
Ω _ closed
Ωm( z) CΩ( z) DΩ( z) GΩ( z)
( z)
= =
Ω ( z) 1 + C ( z) D ( z) G ( z) F( c)
m_
ref
Ω Ω Ω
(5.95)
And finally
G
=
Ω _ closed
( z)
=
K
( K + K )( z−b)( z−
) aA
pΩ
pΩ iΩ 1
Ωd
KpΩ
+ KiΩ
K
z bz c z z z b K K z aA a z
2
pΩ
( − + )( −1)( −1)( −
1) + (
pΩ +
iΩ)( − )
Ωd
1( + 1)
KpΩ
+ KiΩ
(5.96)
Selecting
K Ω
, K Ω
will influence poles placement of closed speed control loop and as
p
i
a consequence also speed step responses can be selected.
In order to select the best value of PI speed controller it is recommended to use the
SISO tools from Matlab package to tune the parameter of PI speed controller.
The speed response with digital filter simulated in SIMULINK is shown in Fig. 5.50
and simulated in SABER in Fig. 5.51 is presented.
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