Peak Recovery Current in Inverter Diode.

Thread Starter


Joined Sep 19, 2018
Does the peak recovery current in a flyback diode, given as a 'current per time', inform about the capacity of an H-Bridge circuit to handle back EMF?

For instance, I have an H-Bridge module comprising four IGBTs with flyback/inverter diodes incorporated in the circuit [Vincotech FZ074PA075SM] which is intended to reverse a current of around 50A in the circuit to field coils of electromagnets with a total inductance of 15mH. The module is rated for 75A with isolation voltage of 6,000V.

My calculations suggest that with a switching time of 1 microsecond, back EMF voltage spikes of the order of 750,000V will be elaborated (and more if the switching time is less). According to the data sheet, the peak recovery current for the inverter diodes, which I suppose to be flyback diodes for the purpose of accommodating this effect, is given as 1000A per microsecond.

My question is whether these diodes will in fact permit the IGBTs to facilitate the reversal of a 50A current in this application as fast as 1 microsecond, or indeed, 200 nanoseconds.