ABB ACQ80, Firmware Manual

Page: 57 / 390

Program features 57
Settings
• Menu - Primary settings - Motor - Control mode
• Parameter
99.04 Motor control mode
(page
264
) and
99.13 ID run requested
(page
268
).

Speed control performance
The figure below shows the typical speed control performance.

Switching frequency
The drive has two switching frequency settings: reference switching frequency
and minimum switching frequency. The drive tries to keep the highest allowed
switching frequency (= reference switching frequency) if thermally possible, and
then adjusts dynamically between the reference and minimum switching
frequencies depending on the drive temperature. When the drive reaches the
minimum switching frequency (= lowest allowed switching frequency), it starts
to limit output current if the heating up continues.
For derating, see chapter Technical data , section
Switching frequency derating
in
the
Hardware manual
of the drive.
Example 1: If you need to fix the switching frequency to a certain value with
some external filters as required, set both the reference and the minimum
switching frequency to this value and the drive will retain this switching
frequency.
Example 2: If the reference switching frequency is set to 12 kHz and the
minimum switching frequency is set to the smallest available value, the drive
maintains the highest possible switching frequency to reduce motor noise and
only when the drive heats up it will decrease the switching frequency. This is
100
t (s)
T
T
N
(%)
T
load
n
act
-n
ref
n
N
Area < 10% s
T
N
= rated motor torque
n
N
= rated motor speed
n
act
= actual speed
n
ref
= speed reference
Speed control Performance
Static accuracy 20% of motor nominal
slip
Dynamic accuracy < 10% s with 100%
torque step (with
default speed controller
tuning)
Tuned speed
controller
< 2% s with 100%
torque step