SoC estimation using the equation in attached image

Hi ,I have done this code in order to estimate the battery state of chaege (SoC) by using nasa data-set for battery charging and discharging , the data-sets are taking from this website https://ti.arc.nasa.gov/tech/dash/groups/pcoe/prognostic-data-repository/, part no 5 (Battery Data Set) BatteryAgingARC_53_54_55_56

in specific file named B0056.mat

sorry i could not upload it here due to the size of the file

my code as below

clc

clear all

A=load('B0056.mat');

load('B0056.mat');

for i=1:252

Type=B0056.cycle(i).type;

if strcmp(Type,'discharge')==1

Voltage_measured=B0056.cycle(i).data.Voltage_measured;

Current_measured=B0056.cycle(i).data.Current_measured;

Temperature_measured=B0056.cycle(i).data.Temperature_measured;

% Current_charge=B0056.cycle(i).data.Current_load;

% Voltage_charge=B0056.cycle(i).data.Voltage_load;

Current_charge=B0056.cycle(i).data.Current_charge;

Voltage_charge=B0056.cycle(i).data.Voltage_charge;

Time=B0056.cycle(i).data.Time/3600;

Capacity=B0056.cycle(i).data.Capacity;

for j=1:length(Current_charge)

if (j == 1)

SOC0 = 0;

else

State =(SOC0 -(-(Current_charge(j)*(Time(j)-Time(j-1)))./Capacity)*100);

end

end

end

end

SOC=State;

A=[ Voltage_measured', Current_measured',Temperature_measured',Current_charge',Voltage_charge',Time'];

A(1:end,end+1)=SOC;

a=strcat('B0006.cycle(', num2str(i),').charge.xlsx');

xlswrite(a,A);

data = readtable('B0006.cycle(252).charge.xlsx'); % read Excel file as table

data.Properties.VariableNames = {'Voltage Measured','Current Measured','Temp Measured','Current Charge','Voltage Charge','Time','SoC'}

writetable(data,'B0006.cycle(252).charge.xlsx') % write back modified data to excel file

[num,txt,raw] = xlsread('B0006.cycle(252).charge.xlsx');

[v,T,vT]=xlsread('B0006.cycle(252).charge.xlsx');

t=v(:,6);y=v(:,7);

plot(t,y)

xlabel('time')

ylabel('soc')

it does not show error but it does not show the required results as SoC during discharge should decrease from 100 to some points

I also want to get the recharge cycle when SOC=0 but it shows error in SOC=State;

please help me with that

note: the attach image is for the equation of SOC estimation

[NAMRATA MOHANTY]

Hello Sir. I need your help in understanding SOC estimation concept.

Answer 1

[Joel Van Sickel]

Hello Mustafa,

the link to your data set does not work and you did not include the relevant .mat file so it would be particularly hard for anyone to help answer this question.

However, here: State =(SOC0 -(-(Current_charge(j)*(Time(j)-Time(j-1)))./Capacity)*100);

you are not correctly implementing the equation for an integral so this is probably at least part of the problem. Please see: https://www.mathworks.com/help/matlab/ref/integral.html

Regards,

Joel

[Mustafa Ahmed]

thank you sir for your reply

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