What does it mean to reset a leakage inductance (in a flyback converter)

[cmyguo3o]

Hello,

I'm new to this forum and would like to ask a theoretical question: what does it mean to "reset" a leakage inductance? Can you explain the process in some detail and give me some synonyms for this term?

Here is the context:

"In a Flyback converter, the leakages inductances slow down the primary current decay and the secondary current rise. Thus, the current transfer from primary to secondary side is delayed and the secondary peak current is reduced. (...) The diode current reaches its peak when the leakage inductor is reset. Thus, in order to accurately regulate the output current, the leakage inductor current must be taken into account."

Thank you in advance!

 

[ronsimpson]

A inductor is reset when it's voltage is zero. I think in this case its voltage is zero.

A real transformer is not perfect. It has capacitance, resistance and inductance that are outside the perfect transformer model.

Capacitance: Every layer of wire has little capacitors to the next layer of wire. The wire has capacitors to the core. etc
The wire has resistance the causes heat and voltage drop at high current.
The inductance causes a delay. It takes time for the current to ramp up in a transformer. If you put voltage across a transformer it takes time for the voltage to reach the perfect transformer. (Leakage inductance looks like small inductors in the legs of the transformer) The voltage is across the leakage inductance first. With time (uS) the current in the leakage inductors ramps the the voltage drops to 'zero' and not the transformer has voltage to sent to the secondary.

When you take voltage away from the transformer the same delay happens. The leakage inductors, have current and the current needs to return to zero before the voltage on the 'transformer' can reset back to zero.

Hope that helps. You might search the WWW for 'leakage inductance'.

 

[cmyguo3o]

Thank you Ron! So, if I've understood it correctly, "reset" essentially means removal of energy from the inductance, or "discharge".