Motor Control - ABB ACS880 Firmware Manual

614 Parameters
No. Name / Range /
Selection
97

Motor control

97.1 Switching frequency
reference
0.000 ... 24.000 kHz
97.2 Minimum switching
frequency
0.000 ... 24.000 kHz
97.3 Slip gain
0...200 %
97.4 Voltage reserve
-5...50 %
Description
Motor model settings.
When parameter 97.9 Switching freq mode
Custom, defines the switching frequency when it is not
otherwise being internally limited.
Note: This is an expert level parameter and should not
be adjusted without appropriate skill.
Switching frequency reference.
When parameter 97.9 Switching freq mode
Custom, defines a minimum switching frequency
reference. The actual switching frequency will not fall
below this limit under any circumstances.
Note: This is an expert level parameter and should not
be adjusted without appropriate skill.
Note: The drive has internal switching frequency limits
that may override the value entered here.
Minimum switching frequency.
Defines the slip gain which is used to improve the
estimated motor slip. 100% means full slip gain; 0%
means no slip gain. The default value is 100%. Other
values can be used if a static speed error is detected
despite having the setting at full slip gain.
Example (with nominal load and nominal slip of 40
rpm): A 1000 rpm constant speed reference is given to
the drive. Despite having full slip gain (= 100%), a
manual tachometer measurement from the motor axis
gives a speed value of 998 rpm. The static speed error
is 1000 rpm - 998 rpm = 2 rpm. To compensate the
error, the slip gain should be increased to 105%
(2 rpm / 40 rpm = 5%).
Slip gain.
Defines the minimum allowed voltage reserve. When
the voltage reserve has decreased to the set value, the
drive enters the field weakening area.
Note: This is an expert level parameter and should not
be adjusted without appropriate skill.
If the intermediate circuit DC voltage U
the voltage reserve is 5%, the rms value of the
maximum output voltage in steady-state operation is
0.95 × 550 V / sqrt(2) = 369 V
The dynamic performance of the motor control in the
field weakening area can be improved by increasing
the voltage reserve value, but the drive enters the field
weakening area earlier.
Voltage reserve.
Def / Type
FbEq 16b / 32b
is set to 4.500 kHz / real32
1000 = 1 kHz / 1000 =
1 kHz
is set to 1.500 kHz / real32
1000 = 1 kHz / 1000 =
1 kHz
100 % / real32
1 = 1 % / 100 = 1 %
-2 % / real32
= 550 V and
dc
1 = 1 % / 100 = 1 %