Design and Working principle
SIMOREG CCP is distinguished by its compact and space-saving design. The line voltage, the line current, and the armature voltage are recorded in the basic unit. These quantities are used to determine whether a commutation failure has occurred (“conduction-through”).
If this is the case, the following happens:
1. The firing pulses in the SIMOREG DC MASTER are blocked immediately
2. The SIMOREG DC MASTER transmits (via serial interface) an “extinguish command”
to the SIMOREG CCP
3. The SIMOREG CCP extinguishes the thyristors by connecting precharged extinguishing capacitors antiparallel to all thyristors. Consequently, the current commutates from the converter into the SIMOREG CCP. The surge absorbing capacitors
will initially be discharged by the accepted current and then charged reversed. Once
the voltage of the surge absorbing capacitors has reached the value of the motor EMF, the armature current begins to extinguish itself. The armature voltage, however, continues to increase. As soon as it has attained the limiting value, resistors will be
added that accept the energy fed back from the motor during the remaining time of the
4. Fault indication F030 is triggered in the SIMOREG DC MASTER.
5. The SIMOREG CCP recharges the commutation capacitors again in reverse direction
so that a new extinguishing process is possible.
Each time the line voltage is switched on (e.g. by means of a line contactor), the SIMOREG CCP needs approx. 3 s until it is ready for use again because the commutation capacitors first have to be charged.
After one extinguishing process, the SIMOREG CCP requires some time before it becomes operational again. This duration depends on the actions during the extinguishing process and immediately afterwards.
Firstly, the surge absorbing capacitors in the SIMOREG CCP must be recharged to the
required value (approximately 10 s). Secondly, the chopper resistors that during the armature current reduction convert the energy to heat need a cooling time which is calculated by a software algorithm. Depending on the energy to be extinguished, this time can be as long as approximately 20 minutes.
The SIMOREG DC MASTER contains setting and display parameters for the commissioning, operation, monitoring and diagnostics of the SIMOREG CCP. The status of the SIMOREG CCP is signaled via connectors and triggering of the SIMOREG CCP or faulty statuses are signaled via fault and alarm messages.
The necessary data transfer between the SIMOREG DC MASTER and SIMOREG CCP
takes place via the serial interface.