Speed Smoothing Control (Pr. 653, Pr. 654) - Mitsubishi Electric FR-F740 EC Instruction Manual

Parameter
6.14.2

Speed smoothing control (Pr. 653, Pr. 654)

Vibration due to mechanical resonance influences the inverter control, causing the output cur-
rent (torque) to be unstable. In this case, the output current (torque) fluctuation can be reduced
to ease vibration by changing the output frequency.
Pr.
Name
No.
Speed smoothing
653
control
Speed smoothing
654
cutoff frequency
The above parameters can be set when Pr. 160 = 0.
Control block diagram
Speed
command
Fig. 6-106: Control block diagram
Setting method
If vibration due to mechanical resonance occurs, set 100% in Pr. 653, run the inverter at the fre-
quency which generates maximum vibration and check if the vibration will be reduced or not af-
ter several seconds. If effect is not produced, gradually increase the Pr. 653 setting and check
the effect repeatedly until the most effective value is set in Pr. 653.
If vibration becomes large by increasing the Pr. 653 setting, gradually decrease the Pr. 653 set-
ting from 100% to check the effect in a similar manner.
When the vibrational frequency due to the mechanical resonance (fluctuation of torque, speed,
and converter output voltage) is known using a tester and such, set 1/2 to 1 time of the vibrational
frequency to Pr.654. (Setting vibrational frequency range can suppress the vibration better.)
Fig. 6-107: Setting method
NOTE
Depending on the machine, vibration may not be reduced enough or an effect may not be
produced.
FR-F700 EC
Initial Setting
Description
Value Range
The torque fluctuation is reduced to reduce
0 0–200%
vibration due to mechanical resonance.
Set the minimum value for the torque varia-
20Hz 0–120Hz
tion cycle (frequency).
Acceleration/deceleration processing
Current for
torque
0
Output frequency
+
-
Speed smoothing control
Proportional
gain
Pr. 653
Cutoff frequency
Torque
fluctuation
detection range
Pr. 654 159Hz (fixed)
Motor noise, noise reduction
Parameters referred to
—
Frequency
V/f control
output
Voltage output
Cutoff frequency
Pr. 654
Current for
torque
Vibrational frequency
Refer to
Section
I002100E
I002101E
6 - 187