OMD10078 rev F
12
1.2.4 IGBT bridge protection
The inverter input current monitoring is carried out by the current transducer
connected upstream the inverter bridge. Therefore the control logic is able to
distinguish an output short-circuit from an IGBT short-circuit.
The behaviour of the inverter in case of short-circuit on the load has been described
at 2.2.3; the output current is limited and the IGBT bridge current does not reach the
protection threshold.
In case of short-circuit in the inverter bridge, the DC input current increases
immediately and there is no possibility of limitation but stopping the PWM.
In this case the alarm A12 – Max Current Stop is activated and must be reset
manually after having verified the status of the semiconductors.
Picture 10 – IGBT bridge protection
