Parameter descriptions
7.9.5.2 Torque controller
The sensorless field oriented control for ASM (configuration 410) and the sensorless field oriented
control for PSM (configuration 610) can be used for sensorless torque control alternative to the speed
control. The torque control is usable above the
Frequency Limit 624. Below the Frequency Limit 624
the current impression is active with the current reference frequency as reference value. In this case
the torque is not controlled, but results depending on the load and the
Starting current 623. To
achieve a starting in torque control, the reference frequency should be set higher than
Frequency
Limit
624. This is guaranteed in example by setting Minimum frequency 418 > Frequency Lim-
it
624.
f <
Frequency Limit 624: Current impression
f ≥
Frequency Limit 624: Direct Torque Control
The
Frequency Limit 624 is set automatically during the motor setup.
The energy saving function shouldn’t be used when using the Torque controller, since it influences the
control dynamics significantly.
An overview of important parameters for using the Torque Controller is compiled in chapter 6.7.8
“Torque control”.
7.9.5.2.1 Torque reference
The reference torque can be specified as follows:
• Set parameter
n-/T-Control Change-Over 164 to "6 - On" or link it to a digital signal and switch
this on.
• Via parameter
Reference Percentage Source 1 476 or Reference Percentage Source 2 494, select
a source for the reference torque.
For example:
− The reference torque can be set via the arrow keys of the operator panel if the following setting is
selected:
Reference Percentage Source 2 494 = "5 - keypad motorpoti (factory setting)".
− The reference torque can be set via multifunction input 1 (MFI1A) if the following setting is select-
ed:
Reference Percentage Source 1 476 = "1 - analog value MFI1A (factory setting)".
− 100 % Torque refer to the calculated Torque from
Rated Mech. Power 376 (Motor power) and
Rated Speed 372 (Motor nominal speed).
Parameter
Torque 224 shows the actual torque.
Select an applicable operation mode for parameter
Operation Mode Flying Start 645. Refer to chap-
ter 7.3.5 “Flying Start”.
7.9.5.2.2 Upper limit and lower limit of the frequency in Torque Control
767 Frequency Upper Limit
768 Frequency Lower Limit
In many cases limitation of the speed is required in the operating points with reduced or without load
torque, because the speed regulates itself to the torque reference and the load behavior. To avoid an
unintentional speed (mostly too high speeds, in some cases also too small speeds and avoidance of
current impression), the frequency is limited by
Frequency Upper Limit 767 and Frequency Lower
Limit
768 by the speed controller.
As from the limit value the drive is controlled to maximum speed (
Frequency Upper Limit 767 and
Frequency Lower Limit 768), which corresponds to the behavior of the speed controller. Additionally,
the controller limits the speed to
Maximum Frequency 419. This limitation is set by the speed control-
ler – changes in the speed controller affect the speed behavior in the limit area of the 3 mentioned
parameters.
In the current impression, the speed is limited additional to
Minimum Frequency 418 – in Direct
Torque Control this limit is not active.
231
Control functions 06/2013 Operating Instructions
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