Danfoss VLT AutomationDrive FC 302, Руководство по программированию, Страница: 146 / 346

7-00 Speed PID Feedback Source
Option: Function:
[9] Frequency
input 33
[11] MCB 15X
[12] MCB 102
Absolute
The option is only available for MCB 102
Encoder module option with version 4.00 and
newer and when
parameter 17-00 Encoders
Connected is set to [1] Two Encoders .
[13] 24V encoder
27/29
Single signal generated from 24V High
Threshold Logic (HTL) encoder connected to
terminals 27 and 29. Configure the 24V
encoder interface in
parameter group 5.7* 24V
Encoder Input .
Program terminals 27/29 to [0] No operation .
7-00 Speed PID Feedback Source
Option: Function:
The option is named as 24V encoder in
software version 8.XX.
3.8.2 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 big motor.
Illustration 3.47 shows the concept of the feature:
130BE197.10
Set-point
Calculation
External Set-point Ramp
Droop
Speed
PID
Torque
PID
M2
M3
VLT 2
VLT 3
Set-point
Calculation
Ramp
Droop
Speed
PID
-
Set-point
Calculation
Ramp
Droop
Speed
PID
Torque
PID
M1
VLT 1
-
-
Torque
PID
Illustration 3.47 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
frequency converter 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 frequency
converter 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.
Parameter Descriptions
VLT
®
AutomationDrive FC 301/302
144 Danfoss A/S © 10/2018 All rights reserved. MG33MP02
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