Closed-loop thyristor current control
System- and communication configuring D7-SYS - SIMADYN D
5-5
Edition 06.2002
Only the most important connections are shown in the diagram.
The FBs should be programmed in a defined sequence.
FBs EMF, CAV and PC6 have a special internal handshake mechanism
to acknowledge computation of the FBs.
1. PA6
(firing angle actual generation, 6 pulse)
•
User-specific FBs for e.g. higher-level speed control loop
in this interrupt sampling time.
2. EMF (voltage actual value sensing)
3. FCS (field current setpoint output), if the option is required.
4. SOL (switch-over logic stage)
5. CAV (current actual value sensing)
6. CSP (current setpoint calculation)
7. CPC (current pre-control in the discontinuous range)
8. CPI
(current controller)
9. PC6 (firing angle controller)
FB-PA6 should always be configured at the start of the interrupt-
controlled run sequence and FB-PC6 as the last block.
Other blocks can also be configured between these blocks depending on
the processor utilization.
All of the converter-specific function blocks should be configured, in
accordance with the run sequence specified above, in an interrupt task I1
with alarm source LE1 or LE3.
FB–FCS can also be computed in a cyclic task.
The FB–FCS can be removed from the standard software package if the
field current setpoint is not to be entered via SIMADYN D (for SITOR sets
6QG2x, 6QG3x without field device option).
The gating unit computation is started by interrupts in synchronism with
the firing pulse. In steady-state operation (constant firing angle in 50[Hz]
line supplies), the interrupts are every 3.3 ms.
When converting time-dependent quantities, this time data is required to
define the interrupts (equivalent sampling time in the I1=3.3 ms for 50[Hz]
line supplies or 2.7 ms for 60[Hz] line supplies).
The FB–CPC for pre-control in the discontinuous range can be replaced
by a polygon characteristic with a characteristic which has been
specifically plotted.
Run sequence,
function blocks
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