Control Structure In Vvc Plus - Danfoss VLT AutomationDrive FC 300 Design Manual

Introduction
3.2.4 Control Structure in VVC
3 3
Ref.
+

_
P 7-20 Process feedback
1 source
P 7-22 Process feedback
2 source
Illustration 3.3 Control Structure in VVC
See the chapter Active/Inactive Parameters in Different Drive Control Modes in the Programming Guide for an overview of
which control configuration is available, depending on selection of AC motor or PM Non salient motor. In the configuration
shown in Illustration 3.3, 1-01 Motor Control Principle is set to [1] VVC
loop. The resulting reference from the reference handling system is received and fed through the ramp limitation and speed
limitation before being sent to the motor control. The output of the motor control is then limited by the maximum
frequency limit.
If 1-00 Configuration Mode is set to [1] Speed closed loop the resulting reference will be passed from the ramp limitation and
speed limitation into a speed PID control. The Speed PID control parameters are located in parameter group 7-0* Speed PID
Ctrl. The resulting reference from the Speed PID control is sent to the motor control limited by the frequency limit.
Select [3] Process in 1-00 Configuration Mode to use the process PID control for closed loop control of e.g. speed or pressure
in the controlled application. The Process PID parameters are located in parameter group 7-2* Process Ctrl. Feedb and 7-3*
Process PID Ctrl..
18
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VLT
plus
P 4-13
Motor speed
high limit (RPM)
P 1-00
P 4-14
Con g. mode
Motor speed
high limit (Hz)
High
Low
P 4-11
Motor speed
Process
low limit (RPM)
P 4-12
Motor speed
low limit (Hz)
plus Open Loop and Closed Loop Configurations
MG33BE02 - VLT
®
AutomationDrive FC 300 Design Guide, 0.25-75 kW
P 1-00
Con g. mode
P 3-**
Ramp
+

_
P 7-00 Speed PID
feedback source
plus
and 1-00 Configuration Mode is set to [0] Speed open
®
is a registered Danfoss trademark
P 4-19
Max. output freq.
+f max.
Motor
controller
-f max.
P 4-19
Max. output freq.
P 7-0*
Speed Motor
PID controller
+f max.
-f max.