Parameter descriptions
The percentage setting of the
Reference Modulation 750 is basically a function of the leakage induc-
tivity of the machine. The default value was selected such that in most cases the remaining deviation
of 5% is sufficient as a reserve range for the current controller. For the optimization of the controller
parameters, the drive is accelerated with a flat ramp into the area of field weakening, so that the
modulation controller intervenes. The limit is set via parameter
Reference Modulation 750. Then, the
control loop can be excited with a jump function by modifying the reference modulation (changeover
between 95% and 50%). By means of an oscillographed measurement of the flux-forming current
component on the analog output of the frequency inverter, the controlling process of the modulation
controller can be assessed. The course of the signal of the flux-forming current I
sd
should reach the
stationary value after overshooting without oscillation. An oscillating of the course of the current can
be damped by increasing the integral time.
7.9.5.6.1 Limitation of modulation controller
755 Reference Imr Lower Limit
756 Control Deviation Limitation
The output signal of the modulation controller is the internal reference flux. The controller output and
the integrating part are limited via the parameter
Reference Imr Lower Limit 755 or the product of
Rated Magnetising Current 716 and Flux Reference Value 717. The magnetizing current parameter
forming the upper limit is to be set to the rated value of the machine. For the lower limit, select a
value which also builds up an adequate flux in the machine in the field weakening area. The limitation
of the control deviation at the output of the modulation controller prevents a possible oscillation of the
control loop in the case of load surges. The parameter
Control Deviation Limitation 756 is stated as
an absolute value and acts both as a positive and a negative limit.
Reference Imr Lower Limit
Control Deviation Limitation
I
FIN
: Nominal value of frequency inverter
o
c
: Overload capacity of frequency inverter.
7.9.6 Real-time tuning (optimizing motor parameters in operation)
1520 Operation mode real-time tuning
Motor parameters measured during commissioning (setup) at standstill will change during operation,
e.g. as a result of changing motor winding temperatures. Real-time tuning compensates these chang-
es. While the drive is running, the controller settings are adjusted continuously to changing motor
properties and the control behavior is optimized. Real-time tuning can be used in V/f characteristic
control (
Configuration 30 = 110) and the field-orientated control methods (Configuration 30 = 410
or 610).
Parameter
Operation mode real-time tuning 1520 enables the following settings:
− Activation of real-time tuning.
− Optimized control parameters are to be saved after shut-down of the frequency inverter.
− Optimized controller parameters are to be applied in a new data set after a data set changeover.
239
Control functions 06/2013 Operating Instructions
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