Mitsubishi Electric FR-A700 Instruction Manual page 122

Speed control by real sensorless vector
control, vector control
(2) Speed feed forward control (Pr. 877 = "1")
⋅ Calculate required torque in responce 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.
(3) Model adaptive speed control (Pr. 877 = "2")
⋅ 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.
⋅ 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, the Pr. 818 Easy gain tuning response level setting needs to be
changed (increased).
(4) Combination of easy gain tuning
The following table indicates the relationships between the speed feed forward/model adaptive speed control and easy
gain tuning function.
Load inertia ratio
(Pr. 880)
Speed control P gain 1
(Pr. 820)
Speed control integral time 1
(Pr. 821)
Model speed control gain
(Pr. 828)
Speed feed forward gain
(Pr. 881)
♦Parameters referred to♦
Pr. 820 Speed control P gain 1, Pr. 830 Speed control P gain 2
Pr. 821 Speed control integral time 1, Pr. 831 Speed control integral time 2
112
Easy Gain Tuning Selection (Pr. 819) Setting
0
Manual input
Manual input
Manual input
Manual input
Manual input
Refer to page 104
1
Inertia ratio estimation value
found by easy gain tuning is
displayed.
Manual input enabled only
during a stop.
Tuning results are displayed.
Write disabled
Tuning results are displayed.
Write disabled
Tuning results are displayed.
Write disabled
Manual input
Refer to page 104
2
Manual input
Tuning results are displayed.
Write disabled
Tuning results are displayed.
Write disabled
Tuning results are displayed.
Write disabled
Manual input