
Notch Filter
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013 121
Notch Filter The 700 Vector has a notch filter in the torque reference loop used
to eliminate mechanical resonance created by a gear train. [Notch Filter Freq]
sets the center frequency for the 2 pole notch filter, and [Notch Filter K] sets the
gain.
Figure 24 Notch Filter Frequency
Due to the fact that most mechanical frequencies are described in Hertz, [Notch
Filter Freq] and [Notch Filter K] are in Hertz as well. The following is an
example of a notch filter.
A mechanical gear train consists of two masses (the motor and the load) and
spring (mechanical coupling between the two loads). See Figure 25
.
Figure 25 Mechanical Gear Train
The resonant frequency is defined by the following equation:
Figure 26
shows a two mass system with a resonant frequency of 62 radians/
second (9.87 Hz). One Hertz is equal to 2ðπ radians/second.
Gain
0 db
Hz
Notch Filter Frequency
Notch Filter K
Jm is the motor inertia (seconds)
Jload is the load inertia (seconds)
Kspring is the coupling spring constant (rad
2
/sec)
resonance Kspring
Jm Jload+()
Jm Jload×
---------------------------------
=
Comentarios a estos manuales