Closed-loop thyristor current control
System- and communication configuring D7-SYS - SIMADYN D
5-59
Edition 06.2002
•
Enter the determined value at input EMF.TA.
If the plant/system configuration has been entirely completed:
→
establish the original configured condition.
5.3.7 Optimizing the current controller
The controller parameters are determined with the field excitation
switched-out (!) and the rotor mechanically locked.
The current controller FB CPI should be optimized with steps, reference
input variable (command variable) = current setpoint. The controller is a
PI controller. The gain CPI.KP and the integral action time CPI.TN should
be separately set. The I component should first be switched-out (CPI.PC
= 1), so that the integral action time CPI.TN is disabled.
•
The current at the discontinuous limit, previously determined, should
be entered at CPC.VCI. The current step to the discontinuous limit
should in this case not result in an increased current.
The basic proportional gain setting, CPI.KP=0.01 for non-discontinuous
operation is a non-critical value.
The current setpoints SOL.WC1 + SOL.WC2 are transferred as sums to
the current controller (SOL.YWC
→
CPI.WC).
•
CPI.TN=10000.0
integral action time [ms]
•
The armature circuit should be closed again.
•
To switch-in the closed-loop current control, the current setpoint
SOL.YWC should be 0.0.
Enable signal to the switch-over logic stage SOL.ION= 0
→
1
The step function circuit used previously can also be used here.
•
The
1
st
step WC
1
of the current setpoint (e.g. connection SOL.WC1)
must be slightly above the discontinuous current limit (CPI.XIT=1).
The value which has already been determined, can be used.
•
In the steady-state (stabilized) status, the 2
nd
step should be switched
to setpoint WC
2
. This should result in a significantly higher current with
respect to the setting for WC
1
. The length of the step must be adapted
to the system situation. The step should be used to trigger the
oscilloscope and trace the current actual value.
•
The proportional gain CPI.KP should be empirically determined for the
"optimum" transition. The user must decide which setting is optimum
for the system. The plots shown below are for several typical settings.
•
After the gain has been determined, the integral component is re-
activated (CPI.PC=0). The armature time constant value is set at input
CPI.TN and the setting should be checked using the current
characteristic, with the same step function as was previously used.
Controller
optimization in the
non-discontinuous
range
