Lenze i950 Series, Manual

Page: 272 / 500

13.6.5.7 Imax controller
Defining the behaviour at the current limit (Imax controller)
The maximum output current or the current limit is defined by the
0x6073 "max. current"
parameter. In case of the V/f characteristic control, an Imax controller is implemented for
complying with this limit. If the motor current exceeds the set maximum current, the Imax
controller is activated.
•
The Imax controller changes the rotating field frequency so that the motor current does
not exceed the current limit. In motor mode, the frequency is reduced and in generator
mode it is increased.
•
The gain and reset time of the Imax controller can be parameterised.
Optimising the Imax controller
The automatic calculation serves to determine starting parameters of the Imax controller
which are sufficient for many applications. Thus, an optimisation is not required for most of
the applications.
The automatic calculation is made via the parameter 0x2822:019 = 1.
The parameters of the Imax controller must be adapted if
•
a power control is implemented with great moments of inertia.
Recommendation:
Step 1: increase reset time in
4
0x2B08:002
Step 2: reduce gain in
4
0x2B08:001
•
vibrations occur with V/f characteristic control during the operation of the Imax controller.
Recommendation:
Step 1: increase reset time in
4
0x2B08:002
Step 2: reduce gain in
4
0x2B08:001
•
overcurrent errors occur due to load impulses or too high acceleration/deceleration
ramps.
Recommendation:
Step 1: reduce reset time in
4
0x2B08:001
Step 2: increase gain in
4
0x2B08:002
Parameter
Address Name / setting range / [default setting] Info
0x2B08:001 V/f Imax controller: Gain
0.000 ... [0.001] ... 1000.000 Hz/A Gain factor Vp of the Imax controller.
0x2B08:002 V/f Imax controller: Reset time
1.0 ... [100.0] ... 2000.0 ms Reset time Ti of the Imax controller.
13.6.5.8 Flying restart controller
Parameter
Address Name / setting range / [default setting] Info
0x2BA1 Flying restart circuit
0 ... [15] ... 100 %
Configuring the motor control
Options for optimising the control loops
Motor control settings
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