For a thermal model of IGBT modules, reverse recovery losses of a switching diode are an important aspect. How and in which part of the module should these losses be modelled? To what extent are these losses dissipated in the IGBT die and/or the diode die?
See part 4 of the article
https://www.researchgate.net/publication/3352942_Losses_in_PWM_inverters_using_IGBTs
Article Losses in PWM inverters using IGBTs
Dear Bram,
the diode will contribute the reverse recovery energy to the dynamic losses, the datasheet will get you a vlaue Erec.
The IGBT that the current commutates to will be burdened with the reverse recovery energy of the diode as well.
Checking the datasheet, the turn-on losses for the IGBT are given, measured in a dedicated experiment and including the diode's charakteristic.
It is important to know, which diode was used in the test, generally it should be the same didoe as the one the IGBT under test in the moduel under consideration is paired with.In case you're charcterizing a single switch, having the same piece as freewheeling diode inside the experiment would be mandator.
The switching (turn-on) energy losses in IGBT can be calculated as the sum of the switch-on energy without taking the reverse recovery process into account and the switch-on energy caused by the reverse recovery of the free-wheeling diode.
Dear Irfan,
the instant the IGBT turns on, the current from the freewheeling diode has to commutate from the diode to the IGBT.
The diode will only start to built up a voltage if the reverse recovery charge has been extracted.
This charge, extracted in a certain time is dQ/dt=I, resembling a current that flows through the IGBT during its turn-on in addition to the load current..
The reverse recovery of the diode thus can NOT be neglected when considering turn-on of the IGBT and the correlating losses.
This also is the exact reason, why the switching losses of an IGBT go down if classical Si-diodes are replaced by SiC-diodes.
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