INVT Goodrive350 Series Operation Manual page 140

Goodrive350 IP55 High-ingress Protection Series VFD
output frequency of the VFD and the linear speed or be calculated through the thickness or
sensor, of which, the linear speed is widely used for the calculation and if using this method, it
is necessary to select whether enable the function of coil diameter limiting.
(3) PID adjustment module: mainly set in P09 group, with two sets of PID parameters available.
The linear speed synchronization and stable tension can be kept through PID adjustment, but
PID parameters can be adjusted according to the site commissioning. Parameters can be
switched between two groups of PID parameters to PID improvement.
(4) Detection and processing module of materials break. The function is valid when enabling
the materials detection.
(5) Pre-drive: if the pre-drive function terminal is valid, when automatic volume-changing, after
starting the VFD, the drum will run at the setting linear speed, if the terminal is invalid, the VFD
will automatically switch to the corresponding control mode.
5.5.20.3 Open-loop tension torque control mode
Open loop means no tension feedback signal; the mode controls the tension through the motor
torque control directly. The rotation speed changes with the linear speed of the material
automatically. The basic is: in frizzy control system, the relationship between the tension F of
the roller with materials, current coil diameter D and output torque of the shaft is: T = F × D /2.
If the output torque can be adjusted according to the variation of coil diameter, the tension can
be controlled. In order to ensure the constant tension in the process of acceleration and
deceleration, there is internal friction compensation module and inertia compensation module
in the VFD to calculate the real time the moment of inertia, and compensate the torque
according to the current speed rate of change. The control principle is:
Tension
reference
Rotational inertia of
mechanical system
Rotational inertia
of material
Relevant modes:
(1) Linear speed input modes: Linear speed input modes: two functions, one is used to count
the synchronous frequency in torque control system according to the linear speed; the other is
used to count the coil diameter according to the linear speed.
(2) Tension setting modes: Set the tension with the control system, need to adjust according to
the actual situation. After confirmation, the value remains the same, and for some need to
improve the winding, tension taper function can be selected to raise the tension with the
Calculate the frequency
according to the tension
+
T=J*dΩ/dt
+
Basic reference
frequency
Inertia torque
compensation
+
+
Friction torque
compensation
-122-
Basic operation guidelines
Motor reference
+
frequency
+