I'm trying to sove this problem. Most of the code is given. Only the while loops must be done. I tried to do it but the calculations never ends.

4 次查看（过去 30 天）
Harri
Harri 2023-12-10
回答： Karl 2023-12-10
% This is the script for completing Task 1e only.
% The input data and modulator parameters are defined here in the same way as
% it was done for tasks 1a - 1d. This part is left unchanged.
% After the part "Initialisation and input data declaration", the specific
% code to implement Task 1e is supposed to be written.
% Step-by-step instructions will be given.
%
% As far as Matlab Grader does not support the Simulink models at the
% moment, Task 1e is supposed to be done partially in local PCs, and partially
% using the Matlab Grader tool in Moodle. Please start completing the task
% here and follow the instruction given further in the code. You will be
% explained all the details there.
%% Initialisation and input data declaratiob (just copied from tasks 1a-1d)
close all; clear all; clc
% Supply network parameters
U_grid_ll = 400; % (V) RMS line-to-line netwotk voltage
U_grid_ph = U_grid_ll/sqrt(3); % (V) RMS phase network voltage
f_grid = 50; % (Hz) network frequency
% Rectified voltage
U_DC = 3*sqrt(2)/pi*sqrt(3)*U_grid_ph; % (V) The average DC voltage of an ideal 6 pulse rectifier
%modulator parameters
m_f = 21; % frequency modulation ratio
m_a = 0.5; % amplitude modulation ratio
f_ref = 50; % (Hz) frequency of reference sine waveform
f_car = m_f * f_ref; % (Hz) carrier frequency (synchronous modulation)
%f_car = m_f * 41; % (Hz) fixed carrier frequency (asynchronous modulation)
% (Uncomment to use instead of synchronous)
T_car = 1/f_car; % (s) carrier wave period
u_tri = 1; % (V) peak triangle voltage
u_ref = m_a * u_tri; % (V) peak reference voltage
SimTime = 1; % (s) simulation length
%% Task 1e
% Step 1. Create the vector of m_a values to be simulated
% The m_a values will be used as x-axis data when building the plot
% We can use 2 options to build the plot. Both will be evaluated as
% acceptable way of task implementation.
% Option 1: Pre-defined m_a-values for a plot accurate enough and fast to run
m_a_vect = [0 0.975 1 1.025 1.05 1.075 1.1 1.13 1.15 1.2 1.3 1.5 2 2.8 4.5]; % m_a values
n_fundplot = length(m_a_vect); % number of the m_a values
% Option 2: Using evenly spaced m_a values (100 values looks good but is very slow 5-10 minutes)
% n_fundplot = 100; % number of m_a-points to run
% m_a_vect = linspace(0,4.5,n_fundplot); % evenly spaced vector with values from 0 to 4.5
% Step 2. Create the values of fundamental output voltage with sinusoidal
% reference waveform
% Note: you are free to do decide on how to switch between sinusoidal reference
% and reference which contains 3rd harmonic. Anyway, this must affect the
% Simulink model. The switching mechanism is suggested to be placed in
% "Sin-Tri PWM", and can be controlled via special variable from this
% script. For example, we can create the variable "Enable_3rd" and write the
% values of 1 or 0 into it.
%set_param('Enable3rd','sw','0')
Enable_3rd = 0 ;
% But, how to implement this switching in the model, you should decide by
% yourself.
% If you did not add any circuit to add 3rd harmonic, the results of THIS
% step will be correct anyway. But, the results of the NEXT step will
% require the 3rd harmonic in reference signal anyway!
% We will use cycle "while" here. If you are good at Matlab, you can use any
% cycle. The objective of this step is to receive the correct values in
% the vector "U_fund_sine".
% Please replace ??? with the suitable lines of the code.
i_sineref = 1; % index for sinusoidal plot points
while(i_sineref <= (n_fundplot)) % create the condition for cycle to work.
% The cycle must run until all the values of m_a
% will be simulated!
m_a = m_a_vect(i_sineref) ; % m_a value for the point to run
u_ref = m_a*u_tri; % [V] peak reference voltage according to m_a
sim('ED_Ex5_T1_Sim',SimTime); % run the model
i_u = length(U_fund.signals.values);% length of the Simulink output signal data, i.e.
% the number of thr last element in the struct "U_fund"
U_fund_sine(i_sineref) = U_fund.signals.values(i_u); % this line picks the last value from signal data
i_sineref = i_sineref ; % increment the "i_sineref" variable to proceed the cycle run
end
% Step 3. Create the values of fundamental output voltage when the
% reference waveform has 3rd harmonic
% This step repeats the previous step but in Simulink model the 3rd
% harmonic must be included in the reference sine signal.
% As was suggested, this can be done if we set:
Enable_3rd = 1;
% REMEMBER: the corresponding circuit/block/function in the model which
% changes its state based on this variable must be done beforehand! If you
% did not modify the model in the way to support the 3rd harmonic in PWM
% reference signal, even correct code from this step will not bring the correct
% result!
% Please replace ??? with the suitable lines of the code.
i_3rd_ext_ref = 1; % index for sinusoidal plot points
while(i_3rd_ext_ref <= (n_fundplot)) % create the condition for cycle to work.
% The cycle must run until all the values of m_a
% will be simulated!
m_a = m_a_vect(i_sineref) ; % m_a value for the point to run
u_ref = m_a*u_tri; % [V] peak reference voltage according to m_a
sim('ED_Ex5_T1_Sim',SimTime); % run the model
i_u = length(U_fund.signals.values); % length of the Simulink output signal data, i.e.
% the number of thr last element in the struct "U_fund"
U_fund_3rd_ext(i_3rd_ext_ref) = U_fund.signals.values(i_u); % this line picks the last value from signal data
i_3rd_ext_ref = i_3rd_ext_ref+1; % increment the "i_3rd_ext_ref" variable to proceed the cycle run
end
save('m_a_vect.txt','m_a_vect','-ASCII'); % This is ready code, don't modify it
save('U_fund_sine.txt','U_fund_sine','-ASCII'); % This is ready code, don't modify it
save('U_fund_3rd_ext.txt','U_fund_3rd_ext','-ASCII'); % This is ready code, don't modify

请先登录，再回答此问题。

回答（1 个）

Karl
Karl 2023-12-10
You need to follow the suggestion given in the comment for the line:
i_sineref = i_sineref ; % increment the "i_sineref" variable to proceed the cycle run

类别

在 Help Center 和 File Exchange 中查找有关 MATLAB 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by