B-H Curve uestion

Yep.

This is a completely programmable inductor, variable with current, with lots of latitude for curve fitting, now with hysteresis, by end of day, hopefully with TC's (using my favorite, all derivatives continuous function... TANH :-)

The existing PSpice model needs lots of core material info. Here all I need is a plot of inductance versus current. ...Jim Thompson

=A0 =A0 ...Jim Thompson

providing

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=A0 =A0 =A0...Jim Thompson

=A0 =A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

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ots

lly

:-)

need

=A0 =A0...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

Ah, yes, the 'saturable core reactor'. Used to use one from Northlake, Chicago, IL ?? to control high voltage DC/DC power supplies. Very efficient way to make a Variable 20kV or 30kV DC supply back in the day of designing Ion Implant Systems. What I liked was that no power to the control winding produced very little output from the HV supply. But put that inductor inside the servo loop and fought that nonlinearity in the transfer curve! That's also when I learned about 'voltage coefficient' of a resistor! At high voltage, resistors were as 'rubbery' as, well, rubber.

Nuh uh. Go back to school. Look at my answer, with a copy of a B-H curve out of a textbook. B-H curves are the history for when drive H up and down between predetermined values -- the curve is different when H isn't driven hard enough to bring the iron fully into saturation (as shown in the dotted part of the graph that I copied).

You _can't_ make the trajectories willy-nilly. But you don't _stay_ on those trajectories unless you meet the original conditions of the curve tracing.

Here's the curve:

Look at my earlier response and take it up with the author if you want to argue.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

I've got 5 pages, about 1 meg, scanned from a book which shows the BH curves when the core is brought up to saturation, when it is less than saturated and

when there is a DC component. It's copyrighted material so posting it here is out of the question but I can email it. Interested?

bg

=A0 =A0 =A0...Jim

=A0 =A0 =A0Thompson

=A0 =A0 =A0| =A0 =A0mens =A0 =A0 | |

=A0 | =A0 =A0 et =A0 =A0 =A0| |

=A0| |

=A0 =A0 =A0 | |

May I ask which book that came from?

Thanks

Klaus

=A0 =A0 ...Jim Thompson

viding

The end

=A0 =A0...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

Also this one, do you know the book reference?

Thanks

Klaus

I posted it already. But:

"Electric Machines: Steady-State Theory and Dynamic Performance", Mulukutla S. Sarma, Wm. C. Brown, 1985

Certainly. Email address, follow the envelope icon on my website. ...Jim Thompson

On Aug 25, 4:18=A0pm, Jim Thompson wrote: ...snip...

ANH

l I

=A0 =A0 ...Jim Thompson

=A0 =A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

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=A0 =A0...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

Jim,

found it!

simply run this in MicroSim Student version, or OrCAD if you got it. If you don't have MicroSim Student Version let me know, it's pretty small simply change the core to suit what you're doing, then change the drive to take you right up to the B=3D0 point and then drive back. bet that plots out well, or send me the core characteristics and I'll see what I can get.

Regards, Robert

BHCURVE - GENERATES A BH CURVE FOR A CORE

• to plot Y trace is B(K1) and X trace is H(K1) .TRAN 1 6 0 1000uS .OPTIONS ITL5=3D0 I1 0 1 SIN(0 .1 1 1) I2 0 1 SIN(0 .2 1 2) I3 0 1 SIN(0 .8 1 3) R1 1 0 1 L1 1 0 200 K1 L1 .9999 KBREAK
• don't forget for PSpice units are in cgs .model KBREAK CORE(AREA=3D3.27156 PATH=3D12.90399 GAP=3D0

ith

TANH

ve

all I

=A0 =A0 ...Jim Thompson

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d.

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=A0 =A0...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 =A0 |

Some useful references for plotting hysteresis curves in PSpice: Prigozy S. (1993): PSPICE Computer Modeling of Hysteresis Effects; IEEE Trans. EDUC-36, 2-5. Prigozy S. (1994): PSPICE Computer Modeling of Power Transformers with Hysteresis Effects; Computers in Education J. Vol. IV No.2, April- June, 68-76.

=A0 =A0...Jim Thompson

=A0 =A0| =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

Almost any version of SPICE incorporates Atherton-Jiles...

I forgot to fill out the subject header, Look for something from bmge at xmission about 10 AM rocky mountain time bg

Got it. Much appreciated! Thanks! ...Jim Thompson

-- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

Here 'tis:

LMAX=Inductance at no current LMIN=Inductance fully saturated I1TH=Current at which inductance has fallen 1/3 of way from LMAX to LMIN I2TH=Current at which inductance has fallen 2/3 of way from LMAX to LMIN ...Jim Thompson

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food.

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I see not only problems with the units in the plot but with the offsets from zero. Seriously non-physical.

?-(

I don't give a rat's ass about B-H, just inductance versus current. :-) ...Jim Thompson

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=A0 =A0 ...Jim Thompson

=A0 =A0...Jim Thompson

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Uh,...B-H is 'origin' of inductance vs current, B-H 'starts' the whole thing.

Jim Thompson a écrit :

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If you do that you'll get AC simulations OK, but your transient simulations will be useless...

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Yes, and it's working isn't it ?:-)

I'm matching the scope photos so closely it's scary. ...Jim Thompson