ASDA-B2
Chapter 6 Control Modes of Operation
Revision May, 2018
6-35
Resonance suppression with low-pass filter
Low-pass Filter
Cut-off Frequency
of Low-pass Filter
= 10000 / P2-25 Hz
-
0db
Resonance
conditions
is suppressed
.
.
Gain
Frequency
Gain
Frequency
Gain
Frequency
Low-pass
Frequency
Low-pass
Frequency
Resonance
Frequency
Attenuation
Rate -3db
Resonance
Point
Resonance
Frequency
When the value of P2-25 is increased from 0, BW becomes smaller. Although it solves the
problem of resonance frequency, the response bandwidth and phase margin is reduced.
Also, the system becomes unstable.
If users know the resonance frequency, notch filter (parameter P2-23 and P2-24) can
directly eliminate the resonance. In this case, notch filter will be more helpful than low-pass
filter. However, if the resonance frequency drifts because of time or other factors, notch
filter will not do.