Chapter 5 Function parameter
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Ch
ap
ter 5
3 to 8: V/F relationship curve between linear V/F and square V/F.
10:VF separate completely mode. In this mode, the output frequency and output voltage is
separated completely, no any relationship at all, the output frequency controlled by frequency
source setting , but output voltage determined by F4.12 setting.(V/F separate voltage supply
source ).V/F separated completely mode can suitable for in inductive heating, inverter power
supply, torque motor, etc applications.
11: V/F semi-separate mode,V is proportional to F in this mode, but the proportional
relationship can be set by F4.12 parameters, furthermore, the V and F proportion also relate to
rated voltage of motor and rated frequency in b0 group.Assume that input voltage source is X ( X
value range from 0~100%), the output voltage V and output frequency F proportion relationship
can be defined as : V/F=2*X*(rated voltage of motor)/(rated frequency of motor)
F4.01 Torque boost
0.0%: automatic torque boost
0.1% to 30.0%
0.0%
★
F4.02 Torque boost cut-off frequency
0.00Hz to F0.19 (maximum
frequency)
15.00Hz
★
Torque boost is mainly used to improve the characteristics of the torque low-frequency under
V/F control mode. If the torque boost is too low, the motor will work at the lower speed and power.
If the torque boost is too high, the motor will run with overexcitation, the inverter's output current
increases and the efficiency is reduced.
It is recommended to increase this parameter when the motor works with heavy load but
without enough torque. The torque boost can be reduced when the load is lighter. When the torque
boost is set to 0.0, the inverter will automatically perform torque boost, the inverter can
automatically calculates the required torque boost value according to the motor stator resistance
parameters.
Torque boost cutoff frequency: torque boost is valid below this frequency, invalid above the
set frequency.
V1
Output frequency
f1
Vb
Output Voltage
fb
V1: Manual torque boost voltage Vb: Maximum output voltage
f1: Manual torque boost cut-off frequency fb: Rated operating frequency
Figure 5-12:
Schematic diagram of manual torque boost voltage
F4.03 Multi-point V/F frequency point F1 0.00Hz~F4.05
0.00Hz
★
F4.04 Multi-point V/F voltage point V1
0.0%~100.0%
0.0%
★
F4.05 Multi-point V/F frequency point F2 F4.03~F4.07
0.00Hz
★
F4.06 Multi-point V/F voltage point V2
0.0%~100.0%
0.0%
★
F4.07 Multi-point V/F frequency point F3
F4.05~b0.04 (rated motor
frequency)
0.00Hz
★
F4.08 Multi-point V/F voltage point V3
0.0%~100.0%
0.0%
★
F4.03 to F4.08 six parameters are used to define multi-point V/F curve.
The multi-point V/F curve is set according to the load characteristics of motor, please be
noted that the relationship between three voltage points and three frequency points must be meet:
V1 <V2 <V3, F1 <F2 <F3. The setting of multi-point V/F curve is as shown in below figure.
In the state of low frequency, if the voltage is set to a higher value, which may cause motor
overheating, even burning, the inverter may appear overcurrent stall or overcurrent protection.
