I don't know where the problem is. I can't get it to plot like this:
This is the code
clear
close all
Z1=500;
Z2=50;
Z3=500;
u=1;
tau1=(2*Z2)/(Z1+Z2);
tau2=(2*Z1)/(Z1+Z2);
tau3=(2*Z3)/(Z3+Z2);
p1=(Z2-Z1)/(Z2+Z1);
p2=(Z1-Z2)/(Z1+Z2);
p3=(Z3-Z2)/(Z3+Z2);
T=2*10^-6;
t=0:50*T/200:50*T;
% a voltage
n=linspace(2,25,length(t));
ua1=tau1*u.*(t>=0);
Uan=(tau1.*tau2.*(p3.^n-1).*(p2.^n-2).*u).*(t>=(n-1)*2*T);
% b voltage
n=linspace(1,25,length(t))
uab=(tau1.*tau3.*(p3.^n-1).*(p2.^n-1).*u).*(t>=n*2*T-T)
syms n % declare n as symbolic variable
F1=symsum(Uan,n,2,25);
F2=symsum(uab,n,1,25)
figure(1)
plot(t,F1+ua1, 'DisplayName', 'F1')
hold on
plot(t,F2, 'DisplayName', 'F2')
hold off
It plots like this:
And it should plot like this
Does anyone know how to fix this?I just started studying matlab and can't find an answer for it. Many thanks.

1 个评论

I think part of the issue is this line of code here:
Uan=(tau1.*tau2.*(p3.^n-1).*(p2.^n-2).*u).*(t>=(n-1)*2*T);
and
uab=(tau1.*tau3.*(p3.^n-1).*(p2.^n-1).*u).*(t>=n*2*T-T)
I think you need parentheses around your exponents, like below:
Uan=(tau1.*tau2.*(p3.^(n-1)).*(p2.^(n-2)).*u).*(t>=(n-1)*2*T);
and
uab=(tau1.*tau3.*(p3.^(n-1)).*(p2.^(n-1)).*u).*(t>=n*2*T-T)
It still doesn't look like your picture, but maybe it's a step closer

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 采纳的回答

hello
this is the correct code
Uan and Uab needs to be 2D arrays (n rows and columns as many as length(t))
also some missing parenthesis as also found by @Jason Shrand
then its fairly straigthforward to do a (one direction) sum (without any need to sym operations)
clear
close all
Z1=500;
Z2=50;
Z3=500;
u=1;
tau1=(2*Z2)/(Z1+Z2);
tau2=(2*Z1)/(Z1+Z2);
tau3=(2*Z3)/(Z3+Z2);
p1=(Z2-Z1)/(Z2+Z1);
p2=(Z1-Z2)/(Z1+Z2);
p3=(Z3-Z2)/(Z3+Z2);
T=2*10^-6;
t=0:50*T/200:50*T;
% a voltage
n=(2:25)';
ua1=tau1*u.*(t>=0);
Uan=(tau1*tau2*(p3.^(n-1)).*(p2.^(n-2))*u).*(t>=(n-1)*2*T);
% b voltage
n=(1:25)';
uab = (tau1*tau3*(p3.^(n-1)).*(p2.^(n-1))*u).*(t>=n*2*T-T);
F1=sum(Uan,1);
F2=sum(uab,1);
figure(1)
plot(t,F1+ua1, 'DisplayName', 'F1')
hold on
plot(t,F2, 'DisplayName', 'F2')
hold off

2 个评论

Your answer is easier to understand, thanks.
as always, my pleasure !

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更多回答(1 个)

More like this perhaps:
Z1=500;
Z2=50;
Z3=500;
u=1;
tau1=(2*Z2)/(Z1+Z2);
tau2=(2*Z1)/(Z1+Z2);
tau3=(2*Z3)/(Z3+Z2);
p1=(Z2-Z1)/(Z2+Z1);
p2=(Z1-Z2)/(Z1+Z2);
p3=(Z3-Z2)/(Z3+Z2);
T=2*10^-6;
t=0:50*T/200:50*T;
% a voltage
n1=2:25;
ua1= @(t) tau1*u.*(t>=0);
% b voltage
n2=1:25;
uab= @(t)sum((tau1.*tau3.*p3.^(n2-1).*p2.^(n2-1).*u).*(t>=(n2*2*T-T)));
figure(1)
plot(t,ua1(t) + Uanfn(n1,t,tau1,tau2,p2,p3,u,T), 'DisplayName', 'F1')
hold on
plot(t,uabfn(n2,t,tau1,tau3,p2,p3,u,T), 'DisplayName', 'F2')
hold off
function Uan = Uanfn(n,t,tau1,tau2,p2,p3,u,T)
Uan = 0;
for i = 1:numel(n)
Uan = (tau1.*tau2.*p3.^(n(i)-1).*p2.^(n(i)-2).*u).*(t>=(n(i)-1)*2*T) + Uan;
end
end
function uab = uabfn(n,t,tau1,tau3,p2,p3,u,T)
uab = 0;
for i = 1:numel(n)
uab = (tau1.*tau3.*p3.^(n(i)-1).*p2.^(n(i)-1).*u).*(t>=(n(i)*2*T-T)) + uab;
end
end

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