Control Structure In Vvc - Danfoss VLT AutomationDrive FC 301 Design Manual

Basic Operating Principles

3.6.3 Control Structure in VVC

3 3
Ref.
+

_
P 7-20 Process feedback
1 source
P 7-22 Process feedback
2 source
Illustration 3.6 Control Structure in VVC
See 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 3.6, 1-01 Motor Control Principle is set to [1] VVC
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 is 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.
20
VLT
+
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)
+ Open Loop and Closed Loop Configurations
®
AutomationDrive FC 301/FC 302 Design Guide, 0.25-75 kW
P 1-00
Con g. mode
P 3-**
Ramp
+

_
P 7-00 Speed PID
feedback source
+
and 1-00 Configuration Mode is set to [0] Speed open loop. The
MG33BF02 - Rev. 2013-12-20
P 4-19
Max. output freq.
+f max.
Motor
controller
-f max.
P 4-19
Max. output freq.
P 7-0*
Motor
Speed
PID controller
+f max.
-f max.