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CTRL/
Modulation
Limit
f
SW
Setting
from LCP
f
SW, ref
f
SW
(load)
f
SW
(U
DC
)
f
SW
( f
m
)
f
SW
(T)
Ramp
PWM
PWM (T)
PWM (f)
Protection
flag
f
SW, ref
f
SW, ref
e
3
0
b
d
5
5
0
.1
0
Illustration 24: Automatic Derating Function Block
7 0 %
f
s w
1 6 0 %
I
m
1 6 k H z @ 6 0 P W M
1 0 k H z @ S F A V M
1 0 k H z @ 6 0 P W M
7 k H z @ S F A V M
C T R L /
m o d u l a t i o n
l i m i t
f
s w
s e t t i n g
f r o m L C P
f
s w , r e f
f
s w , I
f
s w , U D C
f m o t
o r
[
H
z
]
f s
w
[
k H
z
]
1
0
S F A V
M o n l y
1
5
3 .
9 4
9 .
9
f
s
w
,
f
m
2
, f
s
w
,
f
m
3
f
s
w ,
f
m
4
f
s
w
,
f
m
1
f
s w
U
D C , T R I P
U
D C
R e q u e s t e d f
s w
U
D C , S T A R T D E R A T I N G
P W M
f m o t o r [ H z ]
S F A V M
6 0 P W M
o p t i o n a l
8 0 % - 8 6 % o f
f m o t o r , n o m
1 0 H z - 1 5 H z
T
A M B
T
P W M S W I T C H
6 0 P W M
S F A V M
t
2
t
1
T
A M B
H i g h w a r n i n g
L o w w a r n i n g
f
s w
f
s w , f s
f
s w , TAS
f
s
R a m p
f
s w , D S P
f
s w
( I
l o a d
)
f
s w
( U
D C
)
f
s w
( f
m
)
f
s w
( T )
P W M ( T )
P W M ( f
s
)
P W M
e
3
0
b
b
9
7
1
.1
0
Protection flag
(drop to f
s w,min
immediately)
Illustration 25: Interrelationship Between the Automatic Derating Contributions
The switching frequency is first derated due to motor current, followed by DC-link voltage, motor frequency, and then temperature.
If multiple deratings occur on the same iteration, the resulting switching frequency would be the same as though only the most
significant derating occurred by itself (the deratings are not cumulative). Each of these functions is presented in the following sec-
tions.
6.1.9.2 Sine-wave Filter Fixed Mode
When using sine-wave filters, it is important to operate the filters within a safe range of switching frequencies. If the switching fre-
quency is too low, the current through the filter rises, increasing the temperature with risk of damage to the filter.
During programming of the drive, it is possible to select an option for setting a minimum limit for the switching frequency. This
fixed-mode function prevents the swithcing frequencies from being too low.
AJ300847815559en-000101 / 130R0337
40 | Danfoss A/S © 2020.09
Product Features
VLT® AQUA Drive FC 202
Design Guide