Torque Control W/ Freq. Limit - Lenze i55AE125B Manual

Motor control
Optimisation of the control loops
Motor controller settings
8.4.4.8

Torque control w/ freq. limit

In general, the inverter is operated in a mode that controls the motor frequency. Alternatively,
the inverter can be configured in such a way that it controls a motor torque within a defined
frequency range.
Typical applications for such a torque control with frequency limitation are winders and pack-
aging machines.
Preconditions
A torque control is only possible in the motor control type
vector control (SLVC) [4]" or "Servo control (SC ASM) [2]". Thus, first this motor control type
must be configured. For details see the following chapter:
4Sensorless vector control (SLVC)
4Servo control for asynchronous motors (SC-ASM)
After configuring the sensorless vector control (SLVC), one of the following optimisations must
be carried out for a torque control as precise as possible:
4Automatic motor identification (energized)
4Automatic motor calibration (non-energized)
Details
Setpoint selection:
Instead of a frequency setpoint in [Hz], a torque setpoint has to be defined for the torque
•
control. This can be either a value in percent with reference to the rated motor torque set
in 0x6076 (P325.00) or a value in [Nm] if defined via the network.
The standard setpoint source for the torque control can be selected in
•
(P201.03) (default setting: Analog input 1).
Corresponding functions make it possible to change over to other setpoint sources during
•
operation.4Setpoint change-over
Limitation of the torque range:
The positive and negative torque limit can be set independently of each other.
•
Frequency limitation / speed limitation:
The adjustable speed limits serve to protect against very high speeds. High speeds can
•
occur if a pure torque is selected without a counter torque being available (load-free
machine).
The torque control controls the assigned torque setpoint within the set speed limits. The
•
actual speed results from the load conditions of the application. If the actual speed rea-
ches the set speed limits, it is kept on the respective limit value. This protective function is
also called "speed limitation".
The lower and upper speed limit for speed limitation can be set independently of each
•
other. They can also be defined via analog inputs or network.
In the following, the steps required for configuring the torque control with frequency limita-
tion are described.
206
0x2C00 (P300.00)
^ 173
^ 176
^ 199
^ 200
^ 546
= "Sensorless
0x2860:003