76 lines
2.2 KiB
Matlab
76 lines
2.2 KiB
Matlab
%% Skript zu Auslegung eines Trsanformators für einen SMPS
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clear all
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close all
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%%
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p = 1.724e-6; %Spez. Widerstand der Litze [Ohm cm]
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D_max = 0.75; %Maximaler Duty Cycle
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V_in_min = 350; %Minimale Eingangsspannung [V]
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V_in_nom = 511; %Nominelle Eingangsspannung [V]
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V_FET = 0.3; %Spannungsabfall an FETs
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V_D = 0.7; %Durchlassspannung Diode [V]
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V_out = 24; %Ausgangsspannung
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P_out = 1e3; %Maximale <Ausgangsleistung
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P_loss = 0.01 * P_out; %Akzeptable Verlustleistung [W]
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I_out = P_out/V_out; %Ausgangsstrom [A]
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n = ((V_in_min-2*V_FET)*D_max)/(V_out+V_D); %Windungszahlverhältnis
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D_nom = n * (V_out+V_D)/(V_in_nom-2*V_FET); %Nominaler Duty cycle
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fs = 100e3; %Schaltfrequenz [Hz]
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lam1 = V_in_nom *D_nom/fs; % Vs pro Schaltperiode
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I_1_rms = I_out/n * sqrt(D_nom);
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I_2_rms = 0.5 * I_out * sqrt(1+D_nom);
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I_tot = I_1_rms + 2*I_2_rms / n;
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K_fe = 15.76; %Core loss factor (Curve Fitting) [W/Tcm^3]
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Ku = 0.3; %Füllfaktor der Wicklung
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beta = 2.39; %Wert aus Curve Fitting
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Kg_fe = (p*lam1*lam1*I_tot*I_tot*power(K_fe, 2/beta)) / (4*Ku*power(P_loss, (beta+2)/beta)) * 1e8;
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%Angenommen EE40 Kern PC47 --> EE40 könnte Probleme mit Sättigung
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%verursachen
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Ac = 2.4; %[cm^2]
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Wa = 2.29; %[cm^2]
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MLT = 7.7; %[cm]
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lm = 9.86; %[cm]
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A_l = 5340;
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%Peak AC Flux density [T]
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dB = power((1e8*p*lam1*lam1*I_tot*I_tot/(2*Ku)) * (MLT/(Wa*lm*Ac*Ac*Ac) * 1/(beta*K_fe)),1/(beta+2));
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%Primary turns
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n1 = lam1 /(2*dB*Ac)*1e4;
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n2 = n1/n;
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%Runden
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n1_r = round(n1);
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n2_r = round(n2);
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n_r = n1_r / n2_r;
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%Area for windings alpha*Wa ergibt die verfügbare Fläche der Windung
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alpha1 = I_1_rms/I_tot;
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alpha2 = I_2_rms/(n_r*I_tot);
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%Wire sizes
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Aw1 = alpha1*Ku*Wa/n1_r; %[cm^2] Beispiel AWG 23
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Aw2 = alpha2*Ku*Wa/n2_r; %[cm^2] Beispiel AWG 14
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%DC Resistance
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R1 = p * n1_r*MLT/Aw1;
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R2 = p* n2*MLT/Aw2;
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%Verluste berechnen
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B_new = lam1/(2*n1_r*Ac) *1e4;
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P_fe = K_fe * power(B_new,beta) * Ac * lm; %Core losses
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P_cu = (p*lam1*lam1*I_tot*I_tot)/(4*Ku) * MLT/(Wa*Ac*Ac) * 1/(B_new*B_new) * 1e8;
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P_tot = P_fe + P_cu;
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%Magnetizing Inductance berechnen
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Lm = A_l * n1_r * n1_r *1e-9;
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I_1_rms / (Aw1*100)
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I_2_rms / (Aw2*100)
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