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Speed control
4.4.7 Speed estimation gain and current control gain (Pr.730, Pr.824, Pr.825)
(1) Speed control P gain 2 (Pr.730)
Set the proportional gain for the speed estimator with 200 rad/s as 100%.
Setting this parameter higher improves the trackability for speed command changes. It also reduces the speed
fluctuation caused by an external disturbance.
(2) Torque control P gain (Pr.824)
The 100% current loop proportional gain is equivalent to 1000 rad/s.
For general adjustment, make setting within the range 50 to 200% as a guideline.
Set the proportional gain.
Increasing the value improves trackability in response to a current command change and reduces current variation with
disturbance. However, a too large gain will cause instability, generating harmonic torque pulsation.
(3) Torque control integral time (Pr.825)
Set the integral time of current control.
Decreasing the value shortens the time taken to return to the original torque if current variation with disturbance occurs.
(4) Adjustment procedure
Usually, use Pr.820 and Pr.821 for adjustment of the speed control gain, and set "9999 (initial value)" in Pr.730, Pr.824, and
Pr.825.
Make adjustment when any of such phenomena as unusual motor and machine vibration/noise/current and overcurrent
has occurred.
1)Check the conditions and simultaneously change the Pr.824 value.
2)If you cannot make proper adjustment, change the Pr.825 value and repeat step 1).
Adjust if any of phenomena such as unusual vibration, noise, or overcurrent is produced by the motor or machinery.
Parameter
number
Name
Initial
value
Setting
range
Description
730
Speed estimation
P gain
9999
0 to 300% Set the proportional gain for the speed estimator.
9999
MM-GKR motor
The following value is set: 200% for 0.1K and 125% for
0.2K to 0.4K.
S-PM geared
motor
100% is set.
824
Torque control P
gain
9999
0 to 200% Set the current loop proportional gain.
9999
MM-GKR motor
The following value is set: 200% for 0.1K and 150% for
0.2K to 0.4K.
S-PM geared
motor
50% is set.
825
Torque control
integral time
9999
0 to 50ms Set current loop integral compensation time.
9999
MM-GKR motor
The following value is set: 2.5ms for 0.1K and 6.7ms for
0.2K to 0.4K.
S-PM geared
motor
20.0ms is set.
Adjustment Method
Set Pr.824 a little lower and Pr.825 a little higher. First lower Pr.824 and check the motor for unusual vibration/noise and
overcurrent. If the problem still persists, increase Pr.825.
Pr.824
Decrease the value 10% by 10% until just before unusual noise and current are improved, and set about
0.8 to 0.9 of that value.
Note that a too low value will produce current ripples, causing the motor to generate sound synchronizing
the cycle of current ripples.
Pr.825
Increase the current value double by double until just before an unusual noise and current does not occur,
and set about 0.8 to 0.9 of that value.
Note that taking a too long time will produce current ripples, causing the motor to generate sound
synchronizing the cycle of current ripples.