hello

i am working on the veriloga battery model proposed by prof. Mora in the article

http://www.rincon-mora.com/publicat/journals/tec05_batt_modl.pdf

I am beginer and have some problems in implementing that in veriloga.

In the attached schematics there is battery model with nodes.

I did it as follows

module battery(minus, plus, vref);
inout minus, plus, vref;
electrical minus,plus,vref;

electrical vsoc,v1,v2,v3;

parameter real Rdis=10M;
parameter cap=0.015;
real C,capS,capL,vtemp;


analog begin

    @(initial_step) begin
    vtemp =1;
    end
   
    V(vsoc,vref) <+ vtemp;
   
    C=3600*cap;
    capS=-752.9*limexp(-13.51*V(vsoc,vref))+703.6;
    capL=-6056*limexp(-27.12*V(vsoc,vref))+4475;

    I(vsoc,vref) <+ V(vsoc,vref)/Rdis;
    I(vsoc,vref) <+ ddt(C*V(vsoc,vref));
    I(vsoc,vref) <+ I(minus,v1);
   
    V(v1,minus) <+ -1.031*limexp(-35*V(vsoc,vref))+3.685+0.2156*V(vsoc,vref)-0.1178*pow(V(vsoc,vref
),2)+0.3201*pow(V(vsoc,vref),3);
    I(v1,v2) <+ V(v1,v2)/(0.1562*limexp(-24.37*V(vsoc,vref))+0.07446);
   
    I(v2,v3) <+ V(v2,v3)/(0.3208*limexp(-29.14*V(vsoc,vref)));
    I(v2,v3) <+ ddt(capS);
   
    I(v3,plus) <+ V(v3,plus)/(6.603*limexp(-155.2*V(vsoc,vref))+0.04984);
    I(v3,plus) <+ ddt(capL);
   
end


there is one problem, the model is not working

can you advice anything?

regards

let's forget about initial block for a while

it also doesn't work without it. the problem is i'm doing it quite intuitially. the ground at the schematic on the left is vref in the code.

i don't see the problem which happens here

Also, the limexp functions are quite complicated, I can't get any intuition about what's really supposed to happen.  You should probably try simplifying the model -- eg, do you understand the model well enough to turn it into a simple battery with internal series resistance?  Then add the other features, like the increase in resistance as the charge decreases, and make sure each works like you expect before adding the next.

Geoffrey_Coram wrote on Sep 10^th, 2007, 8:03am:


these functions describe transient response of the specific measured battery. it was extracted from measurment results so it looks like it looks.

thanks

grosser wrote on Sep 10^th, 2007, 1:03pm:


Your model is incapable of simulating this situation, in which the battery starts out charged.

Your initial_step code doesn't work because of value retention (did you look that up in the LRM like I suggested?).  If you just take it out ("let's forget about initial block for a while") then the simulation will start with a discharged battery, and presumably it just stays discharged during your simulation.

You need to find a way to start the battery charged; you might be able to use
 if (analysis("ic"))
or you might need to use a nodeset/initial condition specific to your simulator.