Calling a function handle of interp1 to another function handle.

Here, I want to calculate input current based on power demand. Current is calculated based on this formula . But when I run the code it gives nothing even any error. Problem is pwr(t). When I write any constant number like 5 or 9 instead of pwr(t) it works. Then I can observe the graphs but why pwr(t) is not working?

load('Voc.mat'); 
load('power_udds.mat');
socindex=0:0.001:1;
current_index=1:1:1370; 
power_index=0:1:1369;
Nc=1000;         %number of cell     
power=power_udds./Nc;
%--------------------------------------------------------------------------------------------
ocv=@(t,k)interp1(socindex,Voc,(1+k)); % k =y(:,1)
pwr=@(t)interp1(power_index,power,t);  %power demand of the battery
%---------------------------------------------------------------------------------------------
Ro= 0.0048*exp(31.0494/(25+15.3253));
R1=@(t,k)((7.1135e-4) + (-4.3865e-4.*(1+k)) + (2.3788e-4.*(1+k).^2))*exp(347.4707/(25+79.5819));
C1=@(t,k)(335.4518) + (3.1712e3.*(1+k)) + (-1.3214e3.*(1+k).^2) + (53.2138 + (-65.4786.*(1+k)) +(44.3761.*(1+k).^2)).*25;
R2=@(t,k)(0.0288 + (-0.073).*(1+k) + 0.0605.*(1+k).^2)*exp(16.6712./25);
C2=@(t,k)(3.1887e4) + ((-1.1593e5).*(1+k)) + (1.0493e5.*(1+k).^2)+ (60.3114 + 1.0175e4.*(1+k) + (-9.5924e3.*(1+k).^2).*25);
%---------------------------------------------------------------------------------------------
vf=@(t,k,m,n) ocv(t,k)-m-n;   
crrnt=@(t,k,m,n) (vf(t,k,m,n)-sqrt(vf(t,k,m,n).^2-(4*Ro).*pwr(t)))/2*Ro; % Current calculation according to power demand
tspan=[1 1370];
x0=[0;0;0];
[t,y]=ode45(@(t,y)soc(t,y,Q,crrnt,R1,R2,C1,C2),tspan,x0);
%--------------------------------------------------------------
 v= @(t,k,m,n) ocv(t,k)- Ro.*crrnt(t,k,m,n)-m-n; 
%--------------------------------------------------------------------------
function dydt=soc(t,y,Q,crrnt,R1,R2,C1,C2)
    ssoc=1+y(1);
    dydt(1,1)= crrnt(t,y(1),y(2),y(3))./(-3600*Q); 
    dydt(2,1)=(-1/(R1(t,ssoc).*C1(t,ssoc))).*y(2) + (1./C1(t,ssoc)).*crrnt(t,y(1),y(2),y(3));
    dydt(3,1)=(-1/(R2(t,ssoc).*C2(t,ssoc))).*y(3) + (1./C2(t,ssoc)).*crrnt(t,y(1),y(2),y(3));
end

[Adam]

I don't see t defined anywhere in that code, to pass as an argument to

pwr(t)

Also, if you have isolated the error to a given function the first thing you should look to do is test if that function works by itself, outside of all the other code that is there.

In this case you would still run into the issue of needing to define t though.

[Ece Kurt]

Actually, I used ode45 and all t depend ode45 solver.

[Stephen23]

"I don't see t defined anywhere in that code, to pass as an argument to pwr(t)"

crrnt=@(t,k,m,n) (vf(t,k,m,n)-sqrt(vf(t,k,m,n).^2-(4*Ro).*pwr(t)))/2*Ro;
%       ^                                                     ^
[t,y]=ode45(@(t,y)soc(t,y,Q,crrnt,R1,R2,C1,C2),tspan,x0);
%             ^       ^
function dydt=soc(t,y,Q,crrnt,R1,R2,C1,C2)
%                 ^
dydt(1,1)= crrnt(t,y(1),y(2),y(3))./(-3600*Q);
%                ^

[Ece Kurt]

t is a function handle it could have been anything but in the line with ode45 t is the output. I know it is confusing.

Answer 1

[Raunak Gupta]

Hi,

From the code I can see that ‘Q’ is not declared anywhere So, maybe the error is because of that only. Otherwise the script run fine on my side. You may want to check the algorithm that is implemented here for the correctness of the logic.