Function library
Selection of control mode, optimisation of operating behaviour
7−4
L
EDB82MV752 EN 5.2
7.1.1 V/f characteristic control
Description
The output voltage of the controller follows a defined characteristic. At low output frequencies, the
characteristic can be boosted. It can be adapted to different load profiles.
Linear characteristic for drives with constant load torque over the speed.
Quadratic characteristic for drives with quadratic load torque over the speed:
– Quadratic V/f characteristics are preferably used in centrifugal pump and fan drives.
However, it must be checked whether your pump or fan drive can be operated in this
operating mode!
– If your pump or fan drive cannot be used for the operation with a quadratic V/f
characteristic, the linear V/f characteristic or vector control mode must be used.
C0015
V [V]
out
f [Hz]
V
(100 %)
rmot
C0015
V [V]
out
f [Hz]
V
(100 %)
rmot
8200vec540 8200vec539
Fig. 7−2 Linear and square−law V/f characteristic
Codes for parameter setting
Code Possible settings IMPORTANT
No. Name Lenze Selection
C0014
Operating mode 2
2 V/f characteristic control V ~ f
(linear characteristic with constant V
min
boost)
Commissioning is possible without
identifying motor parameters
Advantage of identification with C0148:
– Improved smooth running at low
speeds
– V/f rated frequency (C0015) and slip
(C0021) are calculated and saved.
They must not be entered
7−2
3 V/f characteristic control V ~ f
2
(square−law characteristic with constant V
min
boost)
4 Vector control
In case of the first selection enter the
motor data and identify them with
C0148
Otherwise, commissioning is not
possible
When C0014 = 5, C0019 must be set = 0
(automatic DC injection brake is
deactivated)
5 Sensorless torque control with speed limitation
Torque setpoint via C0412/6
Speed limitation via setpoint 1 (NSET1−N1) if
C0412/1 is assigned, otherwise via maximum
frequency (C0011)
C0015
uSEr
V/f rated frequency 50.00 7.50 {0.02 Hz} 960.00 C0015 is calculated and stored under
C0148 when the motor parameters are
identified
Setting applies to all mains voltages
permitted
7−4
7−8
C0016
uSEr
V
min
boost à 0.00 {0.01 %} 40.00 à Depending on the controller
Setting applies to all mains voltages
permitted
7−4
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