Page 349 - Solutions Manual to accompany Electric Machinery Fundamentals

(c) A version of the program with 1000 Hz reference functions is shown below:

% M-file: probs1_15b.m
% M-file to calculate the output voltage from a PWM
% modulator with a 1000 Hz reference frequency. Note
% that the only change between this program and that
% of part a is the frequency of the reference "fr".

% Sample the data at 20000 Hz to get enough information
% for spectral analysis. Declare arrays.
fs = 20000; % Sampling frequency (Hz)
t = (0:1/fs:4/15); % Time in seconds
vx = zeros(size(t)); % vx
vy = zeros(size(t)); % vy
vin = zeros(size(t)); % Driving signal
vu = zeros(size(t)); % vx
vv = zeros(size(t)); % vy
vout = zeros(size(t)); % Output signal
fr = 1000; % Frequency of reference signal
T = 1/fr; % Period of refernce signal

% Calculate vx at 1000 Hz.
for ii = 1:length(t)
vx(ii) = vref(t(ii),T);
vy(ii) = - vx(ii);
end

% Calculate vin as a 50 Hz sine wave with a peak voltage of
% 10 V.
for ii = 1:length(t)
vin(ii) = 10 * sin(2*pi*50*t(ii));
end

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