Page 149 - Uninterruptible Power Supplies

Static Uninterruptible Power Supplies
Static Uninterruptible Power Supplies 147

35 Apk
14 Arms
21 Apk CF ~ 2.5
10 Arms THD 100%
10 Arms

I S I L
SOURCE
I
R S L S A NON–
AIM
V S FILTER LOAD LINEAR
CURRENT LOAD
SENSE

Figure 5.5

The three waveforms below show the performance of the AIM Filter.
The left hand waveform is a “harmonic-rich” load current waveform that is typical
of “problem” non-linear loads.
In the center is the current waveform from the AIM Filter, which when combined with the
harmonic load current, produces a substantial cancellation of the offending harmonics
resulting in the desired smooth sinusoidal current waveform from the distribution system.
In this particular case, the harmonic content has been reduced from approximately
78 percent to 6 percent, a reduction of 13 to 1.

HARMONIC-RICH WAVEFORM PRESENTED
TO INCOMING SUPPLY
Figure 5.6

mon use. This device is the result of the combination of the properties
of the bipolar transistor and the MOSFET.
The bipolar transistor has advantages of high current and high volt-
age characteristics and the MOSFET of speed and single gate drive

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