I have a 3-phase bridge rectifier which uses IGBT's shown in the image below. The circuit works perfectly and the voltage on the output (unfiltered) is exactly as expected. However the gates are referenced to the collector. Now in order to turn on an IGBT the gate voltage must be greater than gate-emitter voltage.
When I reference them to the emitter the circuit does not work but does work when referenced to collector.
Can anyone clarify why this is??