Pulse Series Connection - Siemens 6RA7086-6KS22 Operating Instructions Manual

Function descriptions
9.20

12-pulse series connection

This function is facilitated by the parameter setting P079 = 2 and is available in SW 2.1 and later.
Two SIMOREG units with identical power are connected in series on the output side and supply a DC
motor.
These two units, which are parameterized as a 12-pulse series master and a 12-pulse series slave,
are coupled via the paralleling interface and fed with electrically isolated line voltages of identical
magnitude with a 30 degree phase displacement.
The power sections of both converters must be supplied with a clockwise phase sequence. The three-
phase system connected on the slave device must lag the system on the master device by 30
degrees.
Balancing resistors must be connected in parallel with the two series-connected single converters.
This is essential to ensure that with low armature currents, or if the armature current = 0, the total
armature voltage is symmetrically divided between the two individual units. It also enables the
armature voltage and the EMF to be correctly calculated internally.
The parameter setting P079 = 2 has the following effect:
•
The firing pulses of the 12-pulse series slave device are output 30 degrees later than the firing
pulses of the master device. Long pulses (pulse duration up to approx. 0.1 ms before next
pulse) are output every 30 degrees on the armature gating unit of both devices, to enable
current to flow if the armature current pulsates.
•
Precontrol for the armature current controller is switched over from 6-pulse operation to 12-
pulse series connection operation. The EMF input value for precontrol (K0122, selection with
P162, P193) must contain half the "total EMF" of the motor.
•
P110 and P111 only have an effect on half the set total motor value. The resistive + inductive
total armature voltage drop is automatically halved for the internal EMF calculation (K0123,
K0124, K0287). If the total armature voltage is symmetrically divided between the two
individual units, then half the total EMF of the motor is calculated. Since the EMF setpoint for
field weakening control (K0289) is also calculated with half the armature circuit resistance
P110/2 (K0289 = P101 - P100*P110 / 2), half the actual rated armature voltage of the motor
must be parameterized at P101.
The slave device must be disconnected from the line and bridged on the output side in order to
perform an optimization run for the current controller and precontrol (P051 = 25) on the 12-pulse
series master device. U800 = 0 must be set on the master device for the duration of the current
controller and precontrol optimization run. The total armature circuit values P110 and P111 for the
motor are set correctly after the current controller and precontrol have been optimized. P156 is also
correct. Only the automatically calculated current controller P gain P155 still needs to be "manually"
halved. In addition, P826.01 to 06 must be set to 0.
For details of the 12-pulse series connection, see the description of applications entitled "12-pulse
operation" (see Section 17).
9-80
SIEMENS AG
SIMOREG DC Master Operating Instructions
05.05
6RX1700-0AD76