Plotting Voltage

M-File Programming For Subplotting:

clc

clear

subplot(2,2,1)

x=0:pi/1800:2*pi;

y=sin(x);

plot(x,y);

title('Plot of sin(x)');

grid

subplot(2,2,2)

x=0:pi/1800:2*pi;

y=sin(x-2*pi/3)

plot(x,y);

title('Plot of sin(x-120)');

grid

subplot(2,2,3)

x=0:pi/1800:2*pi;

y=sin(x+2*pi/3)

plot(x,y);

title('Plot of sin(x-240)');

grid

(try it)

M-File Programming For Three-Phase Voltage:

clc

clear

t=0:pi/1800:2*pi;

v1=100*cos(t);

plot(t,v1);

grid

hold on

v2=100*cos(t-2*pi/3);

plot(t,v2);

v3=100*cos(t+2*pi/3);

plot (t,v3);

title('Plotting Three-Phase Voltage of v1(t), v2(t) and v3(t)')

xlabel ('Time in seconds')

ylabel ('Voltage in volts')

text (6,6,'v1(t)')

text (3,4,'v2(t)')

text (1,1,'v3(t)')

(try it)

Discussion:

· Plotting figure is also called graphing figure in MATLAB.

· In this programming, we can easily draw a different kind of equation’s figure by MATLAB programming.

· In the first programming, we can combine multiple plots on the same page by using calls to the subplot(m,n,p) command.

· This command breaks the figure window into a m-by-n matrix of small subplots and selects the p-th subplot for the current plot.

· The subplots are numbered starting at 1 and increasing along rows to the value max at bottom right of the matrix.

· In the second programming, the program is a sequence of MATLAB commands that will allow us to do this.

· ; at the end of a line defines the command but does not immediately execute it.

· * is used to multiply two functions.

· The command ‘hold on’ keeps the existing graph and adds the next one to it.

· The command ‘plot’ can plot more than one function simultaneously.

· In the plot command we can specify the color line.

· So to say finally, MATLAB allow creating plots of functions easily.