Mitsubishi Electric 800 Series, Instruction Manual, Page: 623 / 727

(G) Control parameters
622
PARAMETERS
 Droop control
• Droop control is enabled for Advanced magnetic flux vector control, Real sensorless vector control, vector control, and PM
sensorless vector control.
• Output frequency will change depending on the size of the current for torque with the droop control.
Set % of the droop amount of rated torque with rated frequency (motor speed in case of Pr.288 = "10, 11") as a reference
for the droop gain.
• Upper limit of the droop compensation frequency is smaller frequency between 400 Hz and Pr.1 Maximum frequency .
• During PM sensorless vector control, the lowest frequency among 400 Hz, Pr.1 , and maximum motor frequency becomes
the upper limit droop compensation frequency.
• The droop compensation frequency is calculated as follows.
NOTE
• Setting of the droop gains should be approximately the rated slip of the motor.
• The speed loop integration can be disabled at the emergency stop using Pr.1349 Emergency stop operation selection .
(Refer to page 269 .)
 Limiting the frequency after the droop compensation (0 limit)
• By setting Pr.288 at the time of Real sensorless vector control, vector control, or PM sensorless control, the negative
frequency command when the frequency after droop compensation can be limited.

During Advanced magnetic flux vector control, the action same as the "0" setting will be performed.
Rated slip =
Synchronized speed at the time of base frequency - rated rotation speed

100 [%]
Synchronized speed at the time of base frequency
Pr.288
setting
Operation
When the output frequency after droop
compensation is negative
Droop compensation
reference
0 (initial value)
No droop control during
acceleration/deceleration
Limited at 0 Hz
(limited at 0.5 Hz under Advanced magnetic flux vector
control)
Rated motor frequency
(
Pr.84 setting)
10  Motor speed
20 
Per-unit speed control
reference frequency
(
Pr.1121 setting)
1 
Continuous droop control during
operation
Rated motor frequency
(
Pr.84 setting)
11
 Motor speed
21 
Per-unit speed control
reference frequency
(
Pr.1121 setting)
2 
Continuous droop control during
operation
Not limited (but reversed) under Vector control or PM
sensorless vector control
Limited at 0 Hz under Real sensorless vector control
Rated motor frequency
(
Pr.84 setting)
22 
Per-unit speed control
reference frequency
(
Pr.1121 setting)
Droop compensation
frequency
Torque
100%
Droop
gain
-100%
Frequency
0
Droop compensation
reference
Current for torque after filtering
Rated torque current
× K × Droop compensation frequency =
Droop compensation reference × Droop gain
100
When the output frequency is equal to or lower than the rated frequency set in Pr.84 : K ＝ 1
When the output frequency is higher than the rated frequency set in Pr.84 : K =
Output frequency
Rated frequency ( Pr.84 )