Oversized ferrite core - is there any problem?

[red_alert]

Hello,

Basically, I want to build a two stage buck converter as a charger for a (solar) battery string.



I want to build those two inductors using some torroidal iron powder cores. I still didn't finish the calculations so I wonder if there's any problem if I'll buy some larger torroidal cores as theoretically needed?

Same question about a ferrite core (double E) for a HF transformer in a pure sine inverter: may I use a larger one? I mean, if a ferrite core could be used for a 5kW buck converter, may I use it for a 500W one?

The (greater) price it's not a problem, I just want it to stay cooler.

Thank you very much for any oppinion.

 

[FvM]

You can, but your calculations should be aware of core losses and leakage inductance.

 

[red_alert]

Actually, I'm trying to build a 2kW charger (24V / 80A output). Could you recommend a suitable iron powder torroidal core (material/physical dimensions)?

Are these **broken link removed** cores a good choice?

 

[hamid159]

you can use.but you have to provide more current to produce flux.Also core losses and leakage inductance will increase.

 

[red_alert]

That means I have to use more turns (to multiplicate both primary and secondary calculated turns)?

LATER EDIT:

I've did some calculations using a software calculator and, for a given ferrite core (E71 from Ferroxcube), the core loses was about 6 watt or something (that was for a 4kW pure sine inverter).

So I guess it's not a big problem to get higher loses (12-15 watt) using a larger ferrite core. And if I'll use thicker Litz wire, I could minimize the copper loses too.

Am I missing something??