Space Vector Modulated – Direct Torque Controlled (DTC – SVM ...

2. Voltage Source Inverter Fed Induction Motor Drive
of the effective switching frequency and switching losses. The discontinuous space
vector modulation techniques, like all the space vector methods, correspond to the
carrier based modulation method. It will be widely described in the next section.
a)
DPWM1
U 3 (010)
t 0 = 0
t 7 = 0
U 2 (110)
1
0.8
U A0
U A
t 0 = 0
t 7 = 0
0.6
0.4
U 4 (011)
t 7 = 0
t 0 = 0
U 0 (000) U 1 (100)
U 7 (111)
0.2
0
-0.2
t 7 = 0
t 0 = 0
-0.4
U N0
t 0 = 0
t 7 = 0
-0.6
-0.8
t 0 = 0
t 7 = 0
U 6 (101)
-1
U 5 (001)
0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02
Time
b)
DPWM2
U 3 (010)
t 7 = 0
U 2 (110)
1
0.8
U A0
0.6
t 0 = 0 t 0 = 0
0.4
U A
U 4 (011)
U 0 (000) U 1 (100)
0.2
0
U 7 (111)
-0.2
t 7 = 0
U 5 (001)
t 0 = 0
t 7 = 0
U 6 (101)
-0.4
-0.6
U
-0.8
N0
-1
0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02
Time
c)
DPWM3
t 7 = 0
U 3 (010)
t 7 = 0
t 0 = 0
t 0 = 0
U 2 (110)
1
0.8
0.6
U A0
U A
U 4 (011)
t 0 = 0
t 0 = 0
t 7 = 0
U 0 (000) U 1 (100)
U 7 (111)
t 7 = 0
0.4
0.2
0
-0.2
-0.4
t 7 = 0
t 7 = 0
U 5 (001)
t 0 = 0
t 0 = 0
U 6 (101)
-0.6
U
-0.8
N0
-1
0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02
Time
d)
DPWM4
U 3 (010)
t 0 = 0
U 2 (110)
1
0.8
0.6
U A
U A0
U 4 (011)
t 7 = 0
t 7 = 0
U 0 (000) U 1 (100)
U 7 (111)
0.4
0.2
0
-0.2
t 0 = 0
t 0 = 0
-0.4
-0.6
U N0
U 5 (001)
t 7 = 0
U 6 (101)
-0.8
-1
0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02
Time
Fig. 2.16. The discontinuous space vector modulation
26