Switching power supplu design

[mixedgas]

Anybody here have experience picking the "ripple factor" constant for designing inductors in buck converters? I'm designing a constant current source for a 155V, 20 amp, arc lamp load. Fixing a 3.5 watt green yag that missing a psu.

I've found 3 on line tutorials with 3 differnent methods and none of them agree.

I need to design a inductor with 100 volts max across it, about 80 volts average, 80-100 khz switching frequency and 18-20 amps flowing through it. Problem is the different explanations for picking the constant very over a factor of 20 or more.

Steve

[Laser Zone]

Anybody here have experience picking the "ripple factor" constant for designing inductors in buck converters? I'm designing a constant current source for a 155V, 20 amp, arc lamp load. Fixing a 3.5 watt green yag that missing a psu.

I've found 3 on line tutorials with 3 differnent methods and none of them agree.

I need to design a inductor with 100 volts max across it, about 80 volts average, 80-100 khz switching frequency and 18-20 amps flowing through it. Problem is the different explanations for picking the constant very over a factor of 20 or more.

Steve

Hey whats up man , Ill let you borrow an lambda eski power supply I have laying around if you want. Im going to FLEM next week so Ill bring it with me. You can borrow it as long as you promise to return it. You can use it as long as you want. Its a 3 phase supply but works just fine with 2 phase. The three phase bridge failed in it so I replaced it with a 2 phase bridge and it works fine. So let me know !

[mixedgas]

Hey whats up man , Ill let you borrow an lambda eski power supply I have laying around if you want. Im going to FLEM next week so Ill bring it with me. You can borrow it as long as you promise to return it. You can use it as long as you want. Its a 3 phase supply but works just fine with 2 phase. The three phase bridge failed in it so I replaced it with a 2 phase bridge and it works fine. So let me know !

Can you hand ito DSLI Jon, I'm gonna miss FLEM due to medical. I can get it from him on his way back.

I love ESKIs and would be feel privilaged to borrow it!

Steve

[Laser Zone]

Ok Steve , no problem !

[Cursorkeys]

Anybody here have experience picking the "ripple factor" constant for designing inductors in buck converters? I'm designing a constant current source for a 155V, 20 amp, arc lamp load. Fixing a 3.5 watt green yag that missing a psu.

I've found 3 on line tutorials with 3 differnent methods and none of them agree.

I need to design a inductor with 100 volts max across it, about 80 volts average, 80-100 khz switching frequency and 18-20 amps flowing through it. Problem is the different explanations for picking the constant very over a factor of 20 or more.

Steve

I see you've now got a supply sorted, but if you are still interested in the design process for inductor ripple I might be able to shed a little light.

Essentially the ripple in the inductor affects the peak currents seen by the drive MOSFETs/IGBTs and also the magnitude of the ripple into the output-filter (a bigger concern if you are looking for low output ripple from the supply).

Although small values of ripple call for a high inductance, the cost of high-voltage storage capacitors greatly outweigh the cost of larger inductors and therefore I'd suggest choosing 10% as your inductor ripple to get the best compromise.

Even if you aren't looking for a low output ripple from your supply I wouldn't advise exceeding 40% inductor ripple as the peak currents in your drive semis are likely to become excessive at the power level you're talking about.

HTH, Jon