Page 339 - Power Electronics Handbook

Output voltage control 329
The harmonics, as calculated from equation (13.21), are given in Tables
13.16-13.19 for values of fdfs = 4, 6, 10, 20 respectively.
It should be noted that for bi-directional switching even harmonics are
absent from the output, apart from the inverter operating frequency and its
triplen harmonics. For unidirectional switching all even harmonics are
missing.
The lower harmonic content with bi-directional switching, when the
inverter operating frequency is higher than the output frequkcy, is less
than for a quasi-square wave. It is also less than that obtained with

Table 13.16 Ii.nwdc content ofa square modulated M-direetioolll wave d&/& = 4

Harmonic R. M.S. voltage as percentage of d.c. supply
number
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
-
~ ~~~ ~~
1 8.6 17.3 26.2 35.1 44.1 53.2 62.4 71.6 80.8 90.0
2 0 0 0 0 0 0 0 0 0 0
3 1.67 3.73 6.16 8.91 12.0 15.3 18.8 22.4 26.2 30.0
4 88.9 85.6 80.2 72.8 63.7 52.9 40.9 27.8 14.1 0
5 1.11 1.48 1.11 0 1.80 4.22 7.18 10.5 14.2 18.0
6 0 0 0 0 0 0 0 0 0 0
7 7.94 14.3 18.7 20.6 20.1 17.1 11.8 4.70 3.74 12.9
8 0 0 0 0 0 0 0 0 0 0
9 8.98 18.1 26.2 32.3 35.6 35.8 32.8 27.0 19.0 10.0
10 0 0 0 0 0 0 0 0 0 0
11 2.17 5.45 9.22 12.8 15.5 16.9 16.7 14.9 11.9 8.18
12 26.7 17.6 4.67 9.27 21.2 28.5 29.6 24.3 13.6 0
13 0.52 0.86 3.79 7.51 11.1 13.6 14.4 13.3 10.6 6.92
14 0 0 0 0 0 0 0 0 0 0
15 7.04 9.68 7.04 0 9.06 17.1 21.4 20.5 14.7 6.00

Tabk 13.17 Hvmonle content ofa square modulated bi-direetiolul wave wlthf& = 6
Harmonic R.M.S. voltage as percentage of d.c. supply
number
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

1 8.82 17.7 26.6 35.6 44.6 53.7 62.7 71.8 80.9 90.0
2 0 0 0 0 0 0 0 0 0 0
3 2.45 5.06 7.83 10.7 13.8 16.9 20.1 23.4 26.7 30.0
4 0 0 0 0 0 0 0 0 0 0
5 0.78 1.86 3.22 4.82 6.66 8.68 10.9 13.2 15.6 18.0
6 88.9 85.6 80.2 72.8 63.7 52.9 40.9 27.8 14.1 0
7 0.41 0.38 0.10 1.00 2.30 3.95 5.90 8.09 10.4 12.9
8 0 0 0 0 0 0 0 0 0 0
9 2.06 3.45 4.10 3.97 3.07 1.44 0.82 3.58 6.70 10.0
10 0 0 0 0 0 0 0 0 0 0
11 8.34 15.3 20.4 23.0 23.2 20.7 15.9 9.04 0.80 8.18
12 0 0 0 0 0 0 0 0 0 0
13 9.02 17.8 25.3 30.8 33.4 33.1 29.7 23.8 15.9 6.92
14 0 0 0 0 0 0 0 0 0 0
15 2.75 6.00 9.25 12.0 13.8 14.5 13.8 12.0 9.25 6.00