Patent ID: 9263933
Filing Date: 2016-02-16
CPC Classification: H02M,H03K

Claim Text:
1. A method for commutating from a first reverse-conducting IGBT operated in a diode mode to a second reverse-conducting IGBT operated in an IGBT mode, said first reverse-conducting IGBT and said second reverse-conducting IGBT electrically connected in series and forming a power converter phase, with the series connection being electrically connected in parallel with a direct-current voltage source, the method comprising the steps of: a) detecting that a control signal of the first reverse-conducting IGBT has switched to an off-state and turning on the first reverse-conducting IGBT after a first predetermined time period has elapsed, b) detecting that a control signal of the second reverse-conducting IGBT has switched to an on-state and turning on the second reverse-conducting IGBT after a second predetermined time period has elapsed, wherein the second time period is substantially greater than the first time period, and c) turning off the first reverse-conducting IGBT when a measurement voltage induced in a saturable transformer by a zero crossing of a collector current in the first reverse-conducting IGBT that is caused by an onset of a current flow through the second reverse-conducting IGBT exceeds a predetermined threshold value.