Stabilizing Speed (Automatic Frequency Regulator) - Omron VARISPEED F7 User Manual

Stabilizing Speed (Automatic Frequency Regulator)

The speed feedback detection control (AFR) function controls the stability of the speed when a load is sud-
denly applied or removed. It calculates the amount of speed fluctuation using the torque current (Iq) feedback
value and compensates the output frequency with the amount of fluctuation.
f
ref
I
q
Related Parameters
Parameter
No.
n2-01 Speed feedback detection control (AFR) gain
n2-02 Speed feedback detection control (AFR) time constant
n2-03 Speed feedback detection control (AFR) time constant 2
Setting the AFR Gain (n2-01)
Normally there is no need to change this setting. If adjustments are necessary do the following:
If hunting occurs increase n2-01.
If the response is too low, decrease n2-01.
Adjust the setting by 0.05 at a time while checking the response.
Setting the AFR Time Constants 1 and 2 (n2-02, n2-03)
Normally the setting value of n2-02 is used as AFR time constant (T in
used when:
L2-04 is set to 1 or 2 AND
output frequency > 5 Hz AND
a transient load change occurs (causing transient regeneration or overshoot at acceleration).
If OV faults occur (e.g. at the end of the acceleration) increase n2-02 and especially n2-03.
In order to prevent hunting effects caused by different response behaviours of the AFR and the Torque Com-
pensation function C4-02 should be increased together with n2-02 and n2-03.
Fig 6.47 AFR Control Loop
Factory
Name
Setting
1.00
50 ms
750 ms
f
out
Control Methods
Change
during
Open
V/f with
Opera-
V/f Loop
PG
tion
Vector
No No No A
No No No A
No No No A
Fig 6.47). The setting value of n2-03 is
Closed
Loop
Vector
No
No
No
6
45
6-