D

#### D from BC

- Jan 1, 1970

- 0

Here's what's on my inductor:

Voltage: 240Vpp 40% duty square wave @ 100khz

Current: +/-100mA triangle wave hovering around 1.5amps.

L=1.3mH

u=125

Problem:

1) What's Bmax

2) What's delta B

I thought about solving this is terms of voltage using

Bmax=(Vrms*10E8)/4.44fAN

But the Vrms is supposed to be from a sine wave...I have squareish.

However, it looks easier to solve in terms of current.

Neglecting the ripple current.. (low impact of accuracy)

and just calling it 1.5Amps of DC current and using:

magnetizing force H

expressed by:

H=(0.4*pie*NI)/l

N=turns

I=peak current Amps

l=magnetic path length cm

along with u = B/H

(u=125)

B can be solved. (Gauss)

Hopefully to be less than the datasheet core sat.

Delta B would be from the +/-100mA or 200mApp.

200mA is put into the B=uH equation.

I'd use that to look up the core loss on the datasheet.

(The more Bchange the more core loss.)

Then I found this eqn:

Bdc=(L*Idc*10E8)/(N*Ac)

L=inductance

Idc=DC amps

N=turns

Ac=cross section cm^2

Which should give the same results.

Have I goofed up somewhere?

D from BC