54 Mentor ll User Guide
www.controltechniques.com Issue Number: 12
This parameter should be set for operation in either single- or four-
quadrant 12-pulse mode. Parameter 05.23 (see above) is read by the
software only at power-on and during a cyclic reset (a reset when the
Drive is disabled).If either of the Bridge 2 quadrants is enabled when
05.23 is read, the outputs are not diverted within the ASIC and 05.23 is
set to 0.
Series 12-pulse mode is phase-sensitive. The rotation on the
stacks must be in the sequence L1, L2, L3 (10.11 = 1).
This parameter instructs the Drive to operate in parallel 12-pulse mode
and should be set for operation in either single- or four-quadrant mode.
For 4-quadrant operation, parameter 05.21 (see above) must be set to 1
and the F10 input of each Drive must be connected to the ST5 output of
the other. Also, the control 0V terminals of both Drives must be
connected.
When enabled (=1) parameter 05.26 applies an additional safety margin
of 1 supply cycle to the bridge changeover logic. This may be required
for highly inductive loads, such as a motor field winding.
When set, enables the continuous auto-tune which continuously
monitors the motor current ripple and adjusts the current loop gains for
optimum performance. The commissioning autotune should still be
carried out because parameter 05.14 is not set by the continuous
autotune.
Calculation of the gains is suspended when the voltage spill-over loop
becomes active so that the gains are not increased when the field is
weakened.
This function does not operate when the Drives are set-up in serial 12-
pulse.
There is hysteresis on a bridge changeover to prevent oscillation
between the two bridges under lightly loaded conditions. In applications
which require fine control of the current the bridge change-over
hysteresis can be reduced from 1.6% to 0.2% of Drive maximum current
by setting this parameter.
IftheDriveisbeingusedwithamotorwithahighinductancearmature
such as elevator motors the current feedback burden resistors can be
increased (by a factor of 1.6 times) to increase the current feedback
signal. This improves the current control at low levels of current. It is
necessary to set this bit parameter if the burdens have been increased
so that the software allow the current limits to remain unchanged.
Setting this parameter affects 05.15 so that it does not have to be set
close to it’s maximum value of 255 when continuous conduction occurs
at very low currents. The autotune routines have been modified to take
this into account.
05.24 Series 12 - pulse operation
RW Bit
ô
0or1
ð
0, disabled
05.25 Parallel 12 - pulse operation
RW Bit
ô
0or1
ð
0, disabled
05.26 Extra-safe bridge change
RW Bit
ô
0or1
ð
0, disabled
05.27 Continuous autotune
RW Bit
ô
0or1
ð
0, disabled
NOTE
05.28
Reduced hysteresis for bridge
changeover
RW Bit
ô
0or1
ð
0, disabled
05.29 Increased current feedback
RW Bit
ô
0or1
ð
0, disabled
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