Mitsubishi Electric 800 Series Instruction Manual page 623

(G) Control 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.
Droop compensation
reference
-100%
• The droop compensation frequency is calculated as follows.
Droop compensation frequency =
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 =
NOTE
• Setting of the droop gains should be approximately the rated slip of the motor.
Rated slip
• The speed loop integration can be disabled at the emergency stop using Pr.1349 Emergency stop operation selection.
(Refer to page
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.
Pr.288
setting
0 (initial value)
10  No droop control during
acceleration/deceleration
20 
1 
11  Continuous droop control during
operation
21 
2 
Continuous droop control during
operation
22 

During Advanced magnetic flux vector control, the action same as the "0" setting will be performed.
622
PARAMETERS
Frequency
0
Current for torque after filtering
Rated torque current
Synchronized speed at the time of base frequency - rated rotation speed
=
Synchronized speed at the time of base frequency
269.)
When the output frequency after droop
Operation
Limited at 0 Hz
(limited at 0.5 Hz under Advanced magnetic flux vector
control)
Not limited (but reversed) under Vector control or PM
sensorless vector control
Limited at 0 Hz under Real sensorless vector control
Droop compensation
frequency
Droop
gain
Torque
100%
Droop compensation reference × Droop gain
× K ×
Rated frequency (Pr.84)
Output frequency
compensation is negative
100

100 [%]
Droop compensation
reference
Rated motor frequency
(Pr.84 setting)
Motor speed
Per-unit speed control
reference frequency
(Pr.1121 setting)
Rated motor frequency
(Pr.84 setting)
Motor speed
Per-unit speed control
reference frequency
(Pr.1121 setting)
Rated motor frequency
(Pr.84 setting)
Per-unit speed control
reference frequency
(Pr.1121 setting)