交流电压波形的正弦脉冲宽度调制simulink.rar

% A Program For Analysis of Sinusoidal Pulse Width Modulation Of An AC % Signal. % By: Yasin A. Shiboul % Date 15/8/2003 % % PART I (preparation) % In this part the screen is cleared, any other functions, figures and % variables are also cleared. The name of the programm is displayed. clc clear all disp('Sinusoidal Pulse Width Modulation of AC Signal') disp(' ') % % PART II % In this part the already known variables are entered, the user is % asked to enter the other variables. % Vrin is the rms value of the input supply voltage in per unit. Vrin=1; % f is the frequency of the input supply voltage. f=input('The frequency of the input supply voltage, f = '); % Z is the load impedance in per unit. Z=1; % ma is the modulation index ma=input('the modulation index,ma, (0<ma<1), ma = '); % phi is load-phase-angle phi=input('the phase angle of the load in degrees = '); % Q is the number of pulses per half-period of the supply voltage. Q=input('The number of pulses per half period = '); % % PART III % Calculating load parameters. % phi=phi*pi/180; % R and L are the load resistance and inductance respectively. R=Z*cos(phi); L=(Z*sin(phi))/(2*pi*f); % % PART IV % Calculating the number of pulses per period,N N=2*Q; % %PART V % Building the Sawtooth signal,Vt, the Input voltage waveform,Vin, % the Output voltage waveform, Vout, and finding the beginning (alpha) % and the end (beta)for each of the output pulses. % In each period of the sawtooth, there is one increasing and decreasing part of % the sawtooth, thus the period of the input supply is divided into % into 2N sub-periods, k is used as a counter of these sub-periods. % for calculation purposes each of these sub-periods is divided into 50 points, i.e., the % input supply period is divided into 100N points. % % j is a counter inside the sub-period % i is the generalized time counter for k=1:2*N for j=1:50 % finding the generalized time counter i=j+(k-1)*50; % finding the time step wt(i)=i*pi/(N*50); % calculating the input supply voltage. Vin(i)=sqrt(2)*Vrin*sin(wt(i)); ma1(i)=ma*abs(sin(wt(i))); % calculating the sawtooth waveform if rem(k,2)==0 Vt(i)=0.02*j; if abs(Vt(i)-ma*abs(sin(wt(i))))<=0.011 m=j; beta(fix(k/2)+1)=3.6*((k-1)*50+m)/N; else j=j; end else Vt(i)=1-0.02*j; if abs(Vt(i)-ma*abs(sin(wt(i))))<0.011 l=j; alpha(fix(k/2)+1)=3.6*((k-1)*50+l)/N; else j=j; end end if Vt(i)>ma*abs(sin(wt(i))) Vout(i)=0; else Vout(i)=Vin(i); end end end beta(1)=[]; % PART VI % Displaying the beginning (alpha), the end (beta) and the width % of each of the output pulses. disp(' ') disp('......................................................................') disp('alpha beta width') [alpha' beta' (beta-alpha)'] % PART VII % Plotting the input voltage waveform Vin, the triangular carrier % signal,Vt,% the modulating signal and the output voltage % waveform, Vout. a=0; subplot(3,1,1) plot(wt,Vin,wt,a) axis([0,2*pi,-2,2]) title('Generation Of The Output Voltage Pulses ') ylabel('Vin(pu)'); subplot(3,1,2) plot(wt,Vt,wt,ma1,wt,a) axis([0,2*pi,-2,2]) ylabel('Vt, m(pu)'); subplot(3,1,3) plot(wt,Vout,wt,a) axis([0,2*pi,-2,2]) ylabel('Vo(pu)'); xlabel('Radian'); % PART VIII % Analyzing the output voltage waveform % Finding the rms value of the output voltage Vo =sqrt(1/(length(Vout))*sum(Vout.^2)); disp('The rms Value of the Output Voltage ') Vo % finding the harmonic contents of the output voltage waveform y=fft(Vout); y(1)=[]; x=abs(y); x=(sqrt(2)/(length(Vout)))*x; disp('The rms Value of the output voltage fundamental component = ') x(1) % Findint the THD of the output voltage THDVo = sqrt(Vo^2 -x(1)^2)/x(1); % PART IX % calculating the output current waveform m=R/(2*pi*f*L); DT=pi/(N*50); C(1)=-10; i=100*N+1:2000*N; Vout(i)=Vout(i-100*N*fix(i/(100*N))+1); for i=2:2000*N; C(i)=C(i-1)*exp(-m*DT)+Vout(i-1)/R*(1-exp(-m*DT)); end % PART X % Analyzing the output current waveform % finding the harmonic contents of the output current waveform for j4=1:100*N CO(j4)=C(j4+1900*N); CO2= fft(CO); CO2(1)=[]; COX=abs(CO2); COX=(sqrt(2)/(100*N))*COX; end % Finding the RMS value of the output current. CORMS = sqrt(sum(CO.^2)/(length(CO))); disp(' The RMS value of the load current is') CORMS %Finding the THD for the output current THDIo = sqrt(CORMS^2-COX(1)^2)/COX(1); % PART XI % Finding the supply current waveform for j2=1900*N+1:2000*N if Vout(j2)~=0 CS(j2)=C(j2); else CS(j2)=0; end end % PART XII % Analyzing the supply current waveform %Supply current waveform and its RMS for j3=1:100*N CS1(j3)=CS(j3+1900*N); end CSRMS= sqrt(sum(CS1.^2)/(length(CS1))); disp('The RMS value of the supply current is') CSRMS % Finding the Fourier analysis CS2= fft(CS1); CS2(1)=[]; CSX=abs(CS2); CSX=(sqrt(2)/(100*N))*CSX; % Finding the THD of the Supply current THDIS = sqrt(CSRMS^2-CSX(1)^2)/CSX(1); % Finding the Displacement Factor of the supply current phi1 = atan(real(CS2(1))/imag(CS2(1)))-pi/2; PF=cos(phi1)*CSX(1)/CSRMS; % PART XIII % Displaying the calculated parameters. disp(' Performance parameters are') THDVo THDIo THDIS PF a=0; %PART XIV % Openning a new figure window for plotting of % the output voltage,output current, supply current and the harmonic % contents of these values figure(2) subplot(3,2,1) plot(wt,Vout(1:100*N),wt,a); title(''); axis([0,2*pi,-1.5,1.5]); ylabel('Vo(pu)'); % subplot(3,2,2) plot(x(1:100)) title(''); axis([0,100,0,0.8]); ylabel('Von(pu)'); subplot(3,2,3) plot(wt,C(1900*N+1:2000*N),wt,a); title(''); axis([0,2*pi,-1.5,1.5]); ylabel('Io(pu)'); subplot(3,2,4) plot(COX(1:100)) title(''); axis([0,100,0,0.8]); ylabel('Ion(pu)'); subplot(3,2,5) plot(wt,CS(1900*N+1:2000*N),wt,a); axis([0,2*pi,-1.5,1.5]); ylabel('Is(pu)'); xlabel('Radian'); subplot(3,2,6) plot(CSX(1:100)) title(''); axis([0,100,0,0.8]); ylabel('Isn(pu)'); xlabel('Harmonic Order');