Parameter Group 7-** Controllers; Speed Pid Droop - Danfoss VLT AutomationDrive EZ FC 321 Programming Manual

VLT® AutomationDrive EZ FC 321
Programming Guide
Selection
Rated torque (0–T )
nom
Power (0–P
nom)
Speed (0–Speed )
max
Option
[0]*
[1]

4.8 Parameter Group 7-** Controllers

4.8.1 Speed PID Droop

This feature implements precise torque sharing between multiple motors on a common mechanical shaft. Speed PID droop is useful
for marine and mining applications where redundancy and higher dynamics are required. Speed PID droop allows to reduce inertia
by utilizing multiple small motors instead of 1 large motor.
External Set-point
Illustration 63: Concept of Speed PID Droop
The value in parameter 7-01 Speed PID Droop ensures that the load is shared equally between the motors. If the torque on the motor
is 100% of nominal motor torque, the drive reduces its output to this motor by 100% of the value in parameter 7-01 Speed PID Droop.
If the torque is 50% of nominal motor torque, the drive reduces its output to this motor by 50% of the value in parameter 7-01 Speed
PID Droop. This ensures that the motors share the load evenly. A side effect of using speed PID droop is that the actual shaft speed
does not match the reference exactly. Speed PID droop is not efficient in low-speed applications because the adjustment range may
be insufficient.
188 | Danfoss A/S © 2021.08
Name
Off
On
Drive 1
Set-point
Ramp
Calculation
Drive 2
Set-point
Ramp
Calculation
Drive 3
Set-point
Ramp
Calculation
0–20 mA
[105]
[106]
[107]
Description
Filter off.
Filter on.
Speed
-
PID
Droop
Speed
-
PID
Droop
Speed
-
PID
Droop
Parameter Descriptions
4–20 mA
[135]
[136]
[137]
Torque
M1
PID
Torque
M2
PID
Torque
M3
PID
AU373327181955en-000101 / 130R1208