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Fine adjustment of gains for speed control
The following table indicates the relationships between the speed feed forward control and easy gain tuning
function.
For details of easy gain tuning, refer to the Instruction Manual (basic) for details.
Pr. 877 Setting
Description
0 Normal speed control is exercised.
1
Speed feed forward control is exercised.
c Calculate required torque in responce to the acceleration/deceleration command for the inertia ratio set in
Pr. 880 and generate torque immediately.
d When inertia ratio estimation has been made by easy gain tuning, the inertia ratio estimation result is used
as the Pr. 880 setting, from which the speed feed forward is calculated.
e When the speed feed forward gain is 100%, the calculation result of the speed feed forward in 1) is
reflected as-is.
f 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 restricted using Pr. 879.
g Using Pr. 878, the speed feed forward result can be dulled by the primary delay filter.
2
Model adaptive speed control is enabled.
At this time, the motor's model speed is calculated to feed back the model side speed controller. This model
speed is also used as the actual speed controller command.
The inertia ratio in Pr. 880 is used for calculation of the torque current command value given by the model
side speed controller.
When inertia ratio estimation has been made by easy gain tuning, Pr. 880 is overwritten by the inertia ratio
estimation result, and that value is used to calculate the torque current command value.
The torque current command value of the model side speed controller is added to the output of the actual
speed controller, and the result is used as the iq current control input.
Pr. 828 is used for model side speed control (P control), and the first gain in Pr. 820 is used for the actual
speed controller. The model adaptive speed control is valid for the first motor only.
When Pr. 877 = 2, switching to the second motor handles the second motor as Pr. 877 = 0.
CAUTION
The adequate gain value for the model and actual loop parts are set according to the responce setting of
easy gain tuning under model adaptive speed control. To increase the responce level, Pr. 818 "responce
setting"needs to be changed (increased).
Easy Gain Tuning Selection (Pr. 819) Setting
012
Load inertia ratio
(Pr. 880)
Manual input
Inertia ratio estimation value
found by easy gain tuning is
displayed.
Manual input enabled only
during a stop.
Manual input
Model speed control gain
(Pr. 828)
Manual input
Tuning results are displayed.
Write disabled.
Tuning results are displayed.
Write disabled.
Speed feed forward gain
(Pr. 881)
Manual input Manual input Manual input
REMARKS
Calculate the inertia reference of the SF-V5RU (H) using the moment of inertia J on page 196.
Related parameters
• Pr. 820 "speed control P gain 1" (Refer to page 175.)
• Pr. 821 "speed control integral time 1" (Refer to page 175.)
• Pr. 830 "speed control P gain 2" (Refer to page 175.)
• Pr. 831 "speed control integral time 2" (Refer to page 175.)