Method for controlling two electrically series-connected reverse conductive IGBTs of a half bridge

摘要

A method for controlling two electrically series-connected reverse-conductive (RC) IGBTs (RC-IBGT) of a half bridge is disclosed, wherein an operating DC voltage is applied across the series connection and one of the two series-connected reverse-conductive IGBTs operates in IGBT mode and another of the two series-connected reverse-conductive IGBTs operates in diode mode, and wherein each of the two reverse-conductive IGBTs has three switching states “+15V”, “0V”, “−15V”. The RC-IGBT T1 operated in diode mode does not go into the switching state (−15V) of highly charged carrier concentration, but instead into a state of medium charge carrier concentration associated with the switching state “0V”, and not into the switching state “−15V”, as is known from conventional methods. This reduces the reverse-recovery without adversely affecting the forward voltage.

主权项

1. A method for controlling two electrically series-connected reverse-conductive IGBTs (RC-IBGT) of a half bridge, wherein an operating DC voltage is applied across the series connection, wherein each of the reverse-conductive IGBTs has three switching states “+15V”, “0V”, “−15V”, the method comprising:
a) setting each of the two reverse-conductive IGBTs to the switching state “−15V” when a nominal control signal associated with the respective reverse-conductive IGBT has a stationary OFF-state, b) holding a reverse-conductive IGBT in the switching state “−15V” after a first predetermined period of time has elapsed and following a switch of the nominal control signal from the OFF-state into an ON-state, as long as a current flows from a collector to an emitter, c) setting a reverse-conductive IGBT to the switching state “+15V” after the first predetermined period of time has elapsed, as long as a current flow from a collector to an emitter is thereby enabled, d) setting each of the reverse-conductive IGBTs into the switching state “+15V” for a third predetermined period of time following a switch of the nominal control signal from the ON-state into the OFF-state, and e) setting each of the reverse-conductive IGBTs into the switching state “0V” for a third predetermined period of time after the second predetermined period of time has elapsed.