Torque Control Algorithms; Constant And Variable Torque; Sensorless Vector Control; Free V/F Control - Omron 3G3MX2 User Manual

"A" Group: Standard Functions
3-5-4

Torque Control Algorithms

Option Terminal
Code Symbol
~
Valid for inputs:
=, >,
Required settings:
>, 
Notes:
• No jogging operation is performed when the
set value of jogging frequency  is smaller
than the start frequency , or the value is
0 Hz.
• Be sure to stop the motor when switching the
function [JG] ON or OFF.
The inverter generates the motor out-
put according to the V/f algorithm

selected. Parameter
inverter algorithm for generating the
frequency output, as shown in the
diagram to the right (
motor). The factory default is
stant torque).
Review the following description to
help you choose the best torque con-
trol algorithm for your application.
The built-in V/f curves are oriented toward developing constant torque or vari-
able torque characteristics (see graphs below). You can select either constant
torque or reduced torque V/f control.
Constant and Variable (Reduced)
Torque - The graph at right shows
the constant torque characteristic
from 0 Hz to the base frequency
The voltage remains constant for out-
put frequencies higher than the base
frequency.
The graph above (right) shows the
variable (reduced) torque
which has a constant torque charac-
teristic from 0 Hz to 10% of the base
frequency. This helps to achieve
higher torque at low speed with
reduced torque curve at higher
speeds.
Sensorless Vector Control - You
can achieve high torque performance
(200% torque at 0.5 Hz of output fre-
quency) without motor speed feedback (encoder feedback), which is so-called
sensorless vector control (SLV control).
Free V/F Control - The free V/F setting function allows you to set an arbitrary
V/F characteristics by specifying the voltages and frequencies (
the seven points on the V/F characteristic curve.
The free V/F frequencies 1 to 7 set by this function must always be in the col-
lating sequence of "1<2<3<4<5<6<7".
Since all the free V/F frequencies are set to 0 Hz as default (factory setting),
specify their arbitrary values (being set with free-setting V/F frequency 7). The
inverter does not operate the free V/F characteristics with the factory setting.
Enabling the free V/F characteristics setting function disables the torque boost
 
selection ( / ), base frequency setting (
Function State
Name
Example (requires input configura-
tion – see page 153):
7
See I/O specs on page 195.
Inverter Torque Control Algorithms
selects the
V/F control
constant torque (V/F-VC)
V/F control,
variable (1.7) torque

for 2nd

(con-
V/F control,
Free V/f
Sensorless vector
Control (SLV)
V
100%

.
0
curve,
V
100%
0
10% Base

Section 3-5
Description
JG FW
6 5 4 3 2 1 L PCS PLC
00
A044
01
02
03
Output
Constant torque
A044 = 00
Base Max.
freq. freq.
Variable torque
A044 = 01
Base Max.
freq. freq. freq.
 
~

/ ), and maximum fre-
P24
Hz
Hz
) for
101