UNIFREM v.3.41x
10 May 2017
Page 58 from 180
Name [ID]
Description
Def.
Torque
Main controlled quantity is the motor torque Torque [69] (page 16).
Speed source [1000]
Setting the rotor speed calculation method, which will be used for
mathematical models and speed regulation.
IRC1
IRC1
Speed feedback is taken from IRC1.
IRC2
Speed feedback is taken from IRC2.
Min(IRC1,IRC2)
Speed feedback is taken as a minimum from IRC1 and IRC2.
Max(IRC1,IRC2)
Speed feedback is taken as a maximum from IRC1 and IRC2.
Average(IRC1,IRC2) Speed feedback is taken as an average between IRC1 and IRC2.
ARC
Speed feedback is read from the absolute positon senosr extension module.
Special
The source of the actual speed is the parameter value Special speed [1002] (page
58).
Special speed [1002]
Parameter that represents the special source of the real rotor speed as an
alternative source of the measured speed.
0,00 Hz
-
1000,00
Hz
÷
1000,00 Hz
If there is need to regulate the speed using the speed voltage generator, its output
connects to an analog input. In special settings of this input this parameter will be
selected as a signal, where the AIN should log. It can be used to configure backup
and support signals in some special applications.
7.5.2 V/f CONTROL
Group of parameters number [81]
Setting the dependence between the output voltage and the frequency (V/f curve) and operation modes
designated for the motor V/f (scalar) control.
V/f CURVE
Group of parameters number [382]
Calculation of the output motor voltage.
MENU \ SETTINGS \ CONTROL AND REGULATION \ V/F CONTROL \ V/F CURVE
Name [ID]
Description
Def.
V/f Type [347]
V/f Curve type. Selecting the features of the V/f control method operation.
□
IR
compensation
Turns on the stator resistance loss compensation [973] (page 59). Requires correct value
of the motor parameters and the stator resistance Stator resistance [345] (page 45).
□ ST controller
Turns on the starting torque controller [29] (page 59) to boost starting torque.
Starting
voltage [90]
Starting voltage of the V/f curve.
0,00 %
0,00 % ÷ 25,00
%
Starting voltage affects torque and motor current in the range of overexcitation, which is
bounded by parameter Frequency shift [98] (page 58). For high torque starts (high friction,
inertia), it should be set higher than the default value preset by motor macro parameters.
Low power motors in general need higher starting voltage than the high power motors.
End
voltage
[94]
End voltage of the V/f curve.
100,0 %
5,0 % ÷ 150,0
%
End voltage is the value of V/f curve at the nominal frequency of Nom. frequency [4] (page
44) . Normally set to 100%, representing a nominal motor voltage. For achieving a slight
power increase, it can be set to more than 100%. Value lower than 100% causes lower
motor excitation in whole speed range and is suitable for testing motor of higher power than
the nominal power of the converter.
Frequency
shift [98]
Frequency shift of the V/f curve.
5,0 Hz
0,0
÷
If the motor has to be overexcited to achieve higher torque in its whole speed range, it can
also be adjusted up to the value of Nom. frequency [4] (page 44), e.g. crane lifts.
V/f
exponent
[91]
V/f curve exponent.
1,00
0,60 ÷ 2,00
Affects the curvature of the whole V/f curve to an exponential shape. The exponent value
1.00 represents the linear shape and the value 2.00 a quadratic process. Using the
exponential V/f curve has its significance in pumps and fans, where the load torque grows
with the rotation speed and field weakening of the motor is allowed at low speed to save
energy.
