I've been attempting to spec a toroidal inductor--what core size, what material and how many turns? I happen to be looking at some made of the material Kool Mu. The material if ferrite, so I presume most of the core loss is hysteretic BH loss, as ferrite doesn't conduct well. Anyway, all I am given is the core loss as a function of frequency and Bmax. They presume that the DC current is zero and the current is entirely AC. But my design requires the core be capable of a large DC current that varies slowly and sinusoidally from -20A to 20A and a small AC current of about 2 amps peak to peak at a much higher frequency. (The low frequency is 60 Hz, and the high frequency is about 100 Khz.) It's the high frequency component that contributes directly to the the lion's share to core heating. Is there a way to infer the core loss when there is a large DC current component when you are given the AC data alone?