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Speed control by Real sensorless vector
control, vector control
4.4.5 Speed feed forward control, model adaptive speed control (Pr. 828, Pr. 877 to Pr.
881)
(1) Speed feed forward control (Pr. 877 = "1")
⋅ Calculate required torque in response to the acceleration/deceleration command for the inertia ratio set in Pr. 880 and
generate torque immediately.
⋅ When the speed feed forward gain is 100%, the calculation result of the speed feed forward is reflected as-is.
⋅ If the speed command changes suddenly, large torque is generated due to the speed feed forward calculation. The
maximum value of the speed feed forward is limited using Pr. 879 .
⋅ Using Pr.878, the speed feed forward result can be dulled by the primary delay filter.
By making parameter setting, select the speed feed forward control or model adaptive speed control.
The speed feed forward control enhances the trackability of the motor in response to a speed command
change.
The model adaptive speed control enables individual adjustment of speed trackability and motor disturbance
torque response.
Parameter
Number
Name Initial Value Setting Range Description
828
Model speed control
gain
60% 0 to 1000% Set the gain for model speed controller.
877
Speed feed forward
control/model
adaptive speed
control selection
0
0 Normal speed control is exercised.
1 Speed feed forward control is exercised.
2 Model adaptive speed control is enabled.
878
Speed feed forward
filter
0s 0 to 1s
Set the primary delay filter for the speed feed
forward result calculated using the speed
command and load inertia ratio.
879
Speed feed forward
torque limit
150% 0 to 400%
Limits the maximum value of the speed feed
forward torque.
880 Load inertia ratio
7 times 0 to 200 times Set the load inertia ratio to the motor.
881
Speed feed forward
gain
0% 0 to 1000% Set the feed forward calculation result as a gain.
POINT
When model adaptive speed control is selected, the data obtained from easy gain tuning is used for Pr. 828 Model
speed control gain. Perform easy gain tuning also (simultaneously). (Refer to page 105)
REMARKS
· The speed feed forward control is enabled for the first motor.
· Even if the driven motor is switched to the second motor while Pr. 877 = 1, the second motor is operated as if Pr. 877 = 0.
Sensorless
Sensorless
Sensorless
Vector
Vector
Vector
Load inertia ratio
J s
[Pr. 880]
[Pr. 881]
[Pr. 820]
Speed feed forward control
Torque control
Speed estimator
Speed
control
P gain 1
Speed control
integral time 1
IM
Actual speed controller
+
-
+
+
+
Speed command
[Block diagram]
Speed feed
forward
gain
Speed feed
forward torque
limit
Speed feed
forward
filter
[Pr. 879]
[Pr. 878]
[Pr. 821]