Page 97 - Power Quality in Electrical Systems

80 Chapter Six

Line reactor

a
Motor
b Controller M

c

Figure 6.6 The line reactor in a motor controller circuit.

result is the trapezoidal waveform of Figure 6.7b, where the commuta-
tion time is the interval m. The reactor does not reduce the 5th and 7th
harmonics significantly, but does reduce the 11th harmonic and higher—
for example, the 11th is reduced from 9.1 to 6.5 percent and the 23rd
from 4.3 to 0.5 percent [6.2]. The reactor will also reduce the magnitude
of the short-circuit current within the converter.

t
0 p 2p

(a)

0 p 2p t
µ
(b)

0 p 2p t
µ
(c)
Figure 6.7 Waveforms of a six-
pulse converter [6.2].
[© 2004, IEEE, reprinted with
t permission]
0 p 2p
(d)