Mitsubishi Electric 800 Series Instruction Manual page 565

5.13.14 Speed smoothing control
V/F V/F V/F
There are times where the vibration due to mechanical resonance affect the inverter, making the output current (torque)
unstable. In such case, vibration can be decreased by reducing the deviation in the output current (torque) by changing the
output frequency.
Pr.
653 Speed smoothing control
G410
654 Speed smoothing cutoff
G411 frequency
 Control block diagram
Acceleration/deceleration
processing
Speed
command
 Setting method
• When vibration caused by mechanical resonance occurs, set 100% in Pr.653 Speed smoothing control, perform
operation at the frequency with the largest vibration, and check if the vibration is suppressed after few seconds.
• If there is no effect, gradually raise the setting value of Pr.653, perform the operation and confirmation of the effect
repeatedly, and use the value (Pr.653) with most effect as the final setting value.
• If the vibration gets larger by raising Pr.653, lower the value of Pr.653 under 100%, and perform the confirmation of result
in a same manner.
• When the vibration frequency (frequency of torque deviation, speed deviation, or converter output voltage deviation) by
the mechanical resonance with a measurement device, etc., set the frequency of 1/2 to 1 times the vibration frequency in
Pr.654 Speed smoothing cutoff frequency. (Setting vibrational frequency range can suppress the vibration better.)
Cutoff frequency
Current for
torque
Torque fluctuation
0
Pr.654
NOTE
• Depending on the equipment, the vibration may not be suppressed sufficiently or the effect is not obtained.
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5. PARAMETERS
5.13 (G) Control parameters
Name Initial value
0%
20 Hz
Output frequency
+
-
Speed smoothing control
Proportional gain
Pr.653
detection range
159 Hz (fixed) Vibrational frequency
Setting range
0 to 200% Confirm the effect by raising and lowering the value with
100% as a reference.
0 to 120 Hz Set the lower limit of the torque deviation cycle (frequency).
Frequency output
V/F control
Voltage output
Cutoff frequency
Pr.654
Current for torque
Description