6-120
îš‹ Increasing the Speed Reference Response (Feed Forward Control)
Use feed forward control to increase the responsiveness to speed references. This function is enabled for
machines for which the ASR gain cannot be increased to a large value because doing so would result in oscil-
lations. There is also the additional effect of making the system less prone to overshoot. This function is valid
only in Flux Vector Control.
Fig 6.75 Overshoot Suppression
îš„Related Parameters
* The default depends on the MxC capacity. The value for a 200 V class MxC of 5.5 kW is given.
Parameter
Number
Name
Description
Setting
Range
Default
Change
during
Run
Control Methods
Display
V/f
Open
Loop
Vector
Flux
Vector
n5-01
Feed Forward
Control Selection
Selects the feed forward controls.
0: Disabled.
1: Enabled.
0 or 1 0 No No No A
Feedfoward Sel
n5-02
Motor Accelera-
tion Time
Sets the time required to accelerate the motor
at the rated torque (T100) to the rated speed
(Nr).
J: (GD
2
) / 4, P: Motor rated output
And
0.001 to
10.000
0.168 s
*
No No No A
Motor Accel Time
n5-03
Feed Forward
Control Ratio Gain
Sets the proportional gain for feed forward
controls.
Response to the speed reference will increase
as the setting of n5-03 is increased.
0.00 to
100.00
1.0 No No No A
Feedfoward Gain
Overshoot
The overshoot is suppressed
at completion of acceleration.
Motor
speed
Motor
speed
Time (s)Time (s)
Feed-forward controlConventional speed control
2π  J[kgm
2
]  Nr[min
-1
]
[sec]ta =
60  T
100
[N
 m]
T
100
=

60

×
10
3
[N

m]
2Ï€
P[kW]
Nr[min
-1
]
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