Bridge Reversal - ABB DCS 600 MultiDrive Series Manual

Chapter 3 – Twelve–Pulse Parallel Configurations with DCS 600

Bridge reversal

In 6 – pulse op-
eration
In 12 – pulse op-
eration
3 - 6
II F2
With a 6 – pulse converter, the bridge reversal is initiated by
changing the polarity of the current reference. Upon zero current
detection, the bridge reversal is started after a delay. Depending on
the moment involved, the new bridge may be "fired" either in the
same or in the next cycle. In addition, switchover can be delayed by
a number of cycles programmed to parameter
This feature may prove useful when operating with large induc-
tances. Then the system changes to the selected bridge without
any further consideration.
If the bridge reversal takes more than 2 control cycles longer
Note:
than the sum of the control cycles programmed to parameters
and
REV DELAY (43.13)
(reversal fault) is activated.
The 12 – pulse bridge reversal function is the same as in 6 – pulse
operation. Depending on the firing angle, the current size, the cur-
rent alteration etc., the zero-current interval is extended by 1 to 2
cycles. In addition, the system delays the bridge reversal until both
current references polarities coincide, or until additional control cy-
cles programmed to parameter
If the bridge signals of master and slave are different for longer
than the control cycles (3.3 ms at 50 Hz) programmed to parameter
REV FAULT DELAY (47.08)
is activated (by the master only). The parameter
must be greater than the sum of parameters
(47.08)
and
(43.13) REV GAP (47.07)
must be set to same values in both converters.
Delay function
REV DELAY (43.13)
Monitoring of master and slave bridge reversal
REV FAULT DELAY (47.08)
Figure 3/3: Time schedule for bridge reversal in 12 – pulse operation
, the fault
REV GAP (47.07)
REV DELAY (43.13)
, the fault
65 "REVER FLT"
. The two parameters
Zero current monitoring
REV GAP (47.07)
DCS 600 Manual for 12 – Pulse Operation
.
REV DELAY (43.13)
65 "REVER FLT"
have elapsed.
(reversal fault)
REV FAULT DELAY
REV DELAY
and
(43.13) (47.07)
Reversal time