Environmental Engineering Reference
In-Depth Information
1.5
U
12
(
i
)
0
1.5
0
100
200
300
400
0
i
359
(a)
1.5
U
23
(
i
)
0
1.5
0
50
100
150
200
250
300
350
400
i
0
359
(b)
1.5
U
31
(
i
)
0
1.5
0
100
200
300
400
i
0
359
(c)
Figure 6.17 SVPWM line-to-line voltages: (a) phase
a
-
b
voltage (
U
12
), (b) phase
b
-
c
voltage (
U
23
) and (c) phase
c
-
a
voltage (
U
31
).
A comparison of various PWM schemes is given in Section 6.6 for
completeness.
6.5 Multilevel inverters
In HV systems such as light rail and other utility interface applications such as the
SST, discussed in Section 6.1, the trend is towards both higher voltage devices and
