67
When power cell bypass mode is symmetrical bypass, once a failed power cell is
bypassed, power cells at the same level output zero voltage to make VFD keep normal
operation.
When the modulation ratio is above maximum modulation ratio of symmetrical bypass
after power cell bypass occurs, VFD output speed will be decreased automatically,
namely bypass derating. Therefore, the actual motor speed becomes lower than the
speed specified by customer. When the modulation ratio is lower than P0392, bypass
derating is finish.
Table 4-68 Negative sequence compensation
ID
Parameter
Min
Max
Unit
Default
Description
P0028
Maximum number of
bypassed power
cells per phase
0
3
0
P0059
Power cell bypass
mode
0
2
0
0-Symmetrical
bypass
1-Reserved
2-Negative
sequence
compensation
P0809
Minimum operating
power factor of
negative sequence
compensation
1
100
0.01
30
P0810
Coefficient of
negative sequence
controller Kp
0
65535
%
100
P0811
Coefficient of
negative sequence
controller Ki
0
65535
%
100
P0812
Filter bandwidth of
negative sequence
current
0
65535
0.1Hz
10
P0813
Maximum
modulation ratio of
negative sequence
compensation
0
1000
0.001
960
P0814
Minimum operating
speed of negative
sequence
compensation
0
100
%
20
When power cell bypass mode is negative sequence compensation, once a failed power
cell is bypassed, other power cells keep normal operation and an imbalance control is
performed to restrain output negative sequence voltage.
When the modulation ratio is above maximum modulation ratio of negative sequence
compensation after power cell bypass occurs, VFD output speed will be decreased
automatically, namely bypass derating. Therefore, the actual motor speed becomes
Summary of Contents for MVF2000 Series
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