Error of Ploting the contour that satisfies a condition

Helle everyone,

I am struggling a bit with a Matlab program that I am writing. I am supposed to create a contour of value with the condition :

From this plot

I want to use the condition the value

M_buck(M_buck > 1 ) = 0.0 ;

M_boost(M_boost < 1) = 0.0 ;

However, only second case (M_boost(M_boost < 1) = 0.0 ;) is working well, the first case have the error in the line as shown

Thank you so much for your support.

Here the the code:

clear all
close all
clc
Vo_max    = 400; 
Pout = 1000;
fs      = 50e3;
Ts     =1/ fs; % half of switching perior
T = 0.5 * Ts;
L = 50e-6; 
Io      =Pout / Vo_max;
n       = 0.5;
R       = Vo_max / Io;
k       = ( T  .* R )./ ( n.^2 .* L );
D = linspace( 0,0.5 , 100 );

D_buck=  linspace( 0.0, 0.5, 1000);
D_boost= linspace( 0.0, 0.5, 1000);
M_buck      = D_buck .* ( 1 - D_buck ) .* k;
M_boost     = D_boost .* ( 1 - D_boost ) .* k;
% condition 
M_buck(M_buck  > 1  ) =  0.0 ;
M_boost(M_boost < 1) =  0.0 ;
[ D_lamda_buck  , M_lamda_buck ] = meshgrid  ( D_buck , M_buck );
[ D_lamda_boost , M_lamda_boost ] = meshgrid (D_boost , M_boost );

lamda_buck = ( ( 2 .* D_lamda_buck -1 )  + M_lamda_buck)        .^2 ./      (( 8 .* D_lamda_buck .*   ( 1 - D_lamda_buck ) .*  ( M_lamda_buck  +1) ) );

lamda_boost =( ( 2 .* D_lamda_boost -1 )  +1./M_lamda_boost ).^2 ./     (( 8 .* D_lamda_boost .*   ( 1 - D_lamda_boost ) .*  ( 1./M_lamda_boost  +1) ) );

%% Plot figures
figure (1)
hold on

[C_buck ,h_lamda_buck]=contour(D_lamda_buck,M_lamda_buck,lamda_buck,[ 0.01 0.05  0.1 0.2 0.25 ], 'color','b');
clabel(C_buck,h_lamda_buck)

[C_boost ,h_lamda_boost]=contour(D_lamda_boost,M_lamda_boost,lamda_boost,[ 0.01 0.05   0.2 0.25 ],'color','r');
clabel(C_boost,h_lamda_boost)
axis([0 0.5 0.5 1.5])

xlabel(' D');
ylabel('M')
grid on
hold off

Answer 1

[Voss]

Does using NaN instead of 0 give the desired result? See below.

clear all
close all
clc
Vo_max    = 400; 
Pout = 1000;
fs      = 50e3;
Ts     =1/ fs; % half of switching perior
T = 0.5 * Ts;
L = 50e-6; 
Io      =Pout / Vo_max;
n       = 0.5;
R       = Vo_max / Io;
k       = ( T  .* R )./ ( n.^2 .* L );
D = linspace( 0,0.5 , 100 );

D_buck=  linspace( 0.0, 0.5, 1000);
D_boost= linspace( 0.0, 0.5, 1000);
M_buck      = D_buck .* ( 1 - D_buck ) .* k;
M_boost     = D_boost .* ( 1 - D_boost ) .* k;

% condition 
M_buck (M_buck  > 1) = NaN ;
M_boost(M_boost < 1) = NaN ;

[ D_lamda_buck  , M_lamda_buck ] = meshgrid  ( D_buck , M_buck );
[ D_lamda_boost , M_lamda_boost ] = meshgrid (D_boost , M_boost );

lamda_buck = ( ( 2 .* D_lamda_buck -1 )  + M_lamda_buck)        .^2 ./      (( 8 .* D_lamda_buck .*   ( 1 - D_lamda_buck ) .*  ( M_lamda_buck  +1) ) );

lamda_boost =( ( 2 .* D_lamda_boost -1 )  +1./M_lamda_boost ).^2 ./     (( 8 .* D_lamda_boost .*   ( 1 - D_lamda_boost ) .*  ( 1./M_lamda_boost  +1) ) );

%% Plot figures
figure (1)
hold on

[C_buck ,h_lamda_buck]=contour(D_lamda_buck,M_lamda_buck,lamda_buck,[ 0.01 0.05  0.1 0.2 0.25 ], 'color','b');
clabel(C_buck,h_lamda_buck)

[C_boost ,h_lamda_boost]=contour(D_lamda_boost,M_lamda_boost,lamda_boost,[ 0.01 0.05   0.2 0.25 ],'color','r');
clabel(C_boost,h_lamda_boost)
axis([0 0.5 0.5 1.5])

xlabel(' D');
ylabel('M')
grid on
hold off

[Tin Truong Chanh]

it works well, thank you so much for your help.

[Voss]

You're welcome!