Intergral calculation for data vector

Question

Raoann 2019-5-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/460937-intergral-calculation-for-data-vector

编辑： Raoann 2019-9-13

Hello,

I need to calculate the toatal energy of solar system and I have the solar power as 43200x1 double. I tried to use trapz and trapezodial method but I get only NAN as the answer. Can somone please guid me how to solve this problem?

So thankful for your help.

%% Iput data from a system: 
 B_V=B_V_12*12;
 Inv_C_Amp=Inv_C_12_5*12.5;
 Sol_C_Amp=Solar_C_12_5*12.5;
 Enr_T_MWh=Energy_tot_0_5*0.5;
 Enr_K_MWh=Energy_kiosk_0_5*0.5;
 Enr_sch_MWh=Energy_school_0_5*0.5;
 %% Calculate the rest of needed data by using the input data:
 Bat_C=Inv_C_Amp-Sol_C_Amp;
 Sol_P_W=Sol_C_Amp.*B_V;
 Inv_P_W=Inv_C_Amp.*B_V;
% Efficiency= Total power out/Power into inverter
Eff=((Enr_T_MWh)./(Inv_P_W*1000000))*100;
Sol_Energy = trapz(t,Sol_P_W );
 
 
%% store Time duration for winter period where the lower temp in July.
 t1=datetime(2018,07,01,2,1,0);
 t2=datetime(2018,07,31,2,0,0);
 t=t1:minutes(1):t2;
 
 
 
 %% Plot the result of the data:
 figure(1)
 subplot(2,2,1)
 plot(t,B_V,'r')
title('Battery voltage');
xlabel('Time');
ylabel('Volt');
subplot(2,2,2)
 plot(t,Bat_C,'r')
title('Battery current');
xlabel('Time');
ylabel('A');
 
subplot(2,2,3)
plot(t,Inv_C_Amp,'b')
title('Inverter current');
xlabel('Time');
ylabel('A');
 
 
 subplot(2,2,4)
plot(t,Sol_C_Amp,'g')
title('Solar current');
xlabel('Time');
ylabel('A');
%Figures for the plower data
figure(2)
subplot(2,1,1)
plot(t,Sol_P_W,'r')
 title('Solar power');
xlabel('Time');
ylabel('Watt');
subplot(2,1,2)
plot(t,Inv_P_W,'b')
 title('Inverter power');
xlabel('Time');
ylabel('Watt');
figure(3)
subplot(3,1,1)
plot(t,Enr_T_MWh,'b')
 title('Total energy provided');
xlabel('Time');
ylabel('MWh');
subplot(3,1,2)
plot(t,Enr_K_MWh,'r')
 title('Energy provided to kiosk');
xlabel('Time');
ylabel('MWh');
 
subplot(3,1,3)
plot(t,Enr_sch_MWh,'r')
 title('Energy provided to school');
xlabel('Time');
ylabel('MWh');
figure(4)
plot(t,Eff,'r')
title('Inverter efficiency');
xlabel('Time');
ylabel('%');
%Energy calculation
% 
% Sol_Energy = trapz(Sol_P_W );
% Sol_Energy= cumtrapz(Sol_P_W)
%  

3 个评论
显示 1更早的评论隐藏 1更早的评论

Abm 2019-5-8

Thank you for responding. No, I don’t have any NAN value in the (Sol_P_W) vector.

Erivelton Gualter 2019-5-8

Can you share the Sol_P_W data?

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Rik 2019-5-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/460937-intergral-calculation-for-data-vector#answer_374150

You define your t vector only after you use it in trapz. But more importantly, your figure looks like you don't mean an integration, but a cumulative sum. In that case you can use the cumsum function to create that plot.

If that is not what you mean, please attach your variables in a mat file.

2 个评论
显示无隐藏无

Raoann 2019-5-8

thank you, Can you please explain how should I write the cumsum function?

Rik 2019-5-8

在 MATLAB Online 中打开

Did you read the documentation? I'm not sure how I should explain it differently, but I'll try anyway.

Suppose you have a much smaller solar output vector and a time vector:

%small example with some jagged peaks
sun=[0 0 1 5 20 20 4 0 0 1 0 5 50 100 100 1 0];
time=linspace(0,30,numel(sun));

Then you can make a plot like you showed in your comment:

sun=[0 0 1 5 20 20 4 0 0 1 0 5 50 100 100 1 0];
time=linspace(0,30,numel(sun));
total_power=cumsum(sun);
figure(1),clf(1)%only use clf during debugging
subplot(2,1,1)
plot(time,sun,'r')
title('Solar power')
subplot(2,1,2)
plot(time,total_power,'r')
title('Total solar energy')
ylim(ylim.*[1 1.1])%extend upper limit a bit