How to plot the magnitude and phase of this Fourier Transform frequency response

Hello ,

I want to write code in MATLAB to get the same plot please. I've tried to learn how to get this plot but I didn't find anything.

I have 3 inductors 478 µH. but I couldn't get the plot looking same.

This is the code that I have created with some help of chat GPT :

%% 1) Define the frequency range for analysis
f = logspace(1, 5, 500);   % Frequency in Hz
w = 2*pi*f;                % Angular frequency

% Given Parameters
Lb = 478e-6; % Phase inductance in H (Lb1 = Lb2 = Lb3)
Cb = 880e-6; % Output capacitance in F
R = 0.1;     % Example ESR or sense resistor

% Control Gains (Placeholder values, adjust for your system)
K_v_gain = 1; % Voltage gain
K_i_gain = 1; % Current gain
K_i_fltr = 1; % Current filter gain
G_d = 1; % Duty cycle transfer function

%% 2) Define s-domain variable and transfer functions
s = tf('s');
Zi = R + s*Lb;   % Impedance of the inductor

% Corrected Current Loop Transfer Function (Hp-i)
Hp_i = 3 * (1 / K_v_gain) * K_i_gain * K_i_fltr * G_d * (1 / Zi);

%% 3) Bode plot of the modeled open-loop gain
figure('Name','Modeled Open Loop Gain','NumberTitle','off');
bode(Hp_i, {2*pi*10, 2*pi*1e5});  % Bode plot from 10 Hz to 100 kHz
grid on;
title('Current Open-Loop Gain (Modeled)');

%% 4) Compare with measured data (if available)
% Replace with actual measured data if available
freq_meas     = [10, 100, 1e3, 10e3, 100e3];   % Hz (example)
mag_meas_dB   = [-5, -2,  0,   -3,   -10];     % dB (example)
phase_meas_deg= [ 0, -30, -60, -90, -120];     % deg (example)

% Extract the model’s magnitude and phase at the same measured frequencies
[mag_model, phase_model] = bode(Hp_i, 2*pi*freq_meas);

% Convert the magnitude (which is dimensionless) to dB
mag_model_dB = 20*log10(squeeze(mag_model));
phase_model_deg = squeeze(phase_model);

%% 5) Plot measured vs. modeled (Magnitude & Phase)
figure('Name','Open Loop Gain Comparison','NumberTitle','off');

subplot(2,1,1);  % Magnitude subplot
semilogx(freq_meas, mag_meas_dB, 'bo-', 'LineWidth',1.5, 'MarkerSize',6); 
hold on;
semilogx(freq_meas, mag_model_dB, 'rx--', 'LineWidth',1.5, 'MarkerSize',6);
grid on; xlabel('Frequency (Hz)'); ylabel('Magnitude (dB)');
legend('Measured','Modeled','Location','Best');
title('Current Open-Loop Gain: Magnitude');

subplot(2,1,2);  % Phase subplot
semilogx(freq_meas, phase_meas_deg, 'bo-', 'LineWidth',1.5, 'MarkerSize',6); 
hold on;
semilogx(freq_meas, phase_model_deg, 'rx--', 'LineWidth',1.5, 'MarkerSize',6);
grid on; xlabel('Frequency (Hz)'); ylabel('Phase (deg)');
legend('Measured','Modeled','Location','Best');
title('Current Open-Loop Gain: Phase');

[EDIT] formatted code as code and ran it.

Answer 1

[Mathieu NOE]

hello

well the code seems to work and the model plot (in red) looks good / in match with your publication

maybe the K -gains) must be also adjusted

simply the experimental values used in the code are off - you may need to put he right data here

%% 1) Define the frequency range for analysis
f = logspace(1, 5, 500);   % Frequency in Hz
w = 2*pi*f;                % Angular frequency

% Given Parameters
Lb = 478e-6; % Phase inductance in H (Lb1 = Lb2 = Lb3)
Cb = 880e-6; % Output capacitance in F
R = 0.1;     % Example ESR or sense resistor

% Control Gains (Placeholder values, adjust for your system)
K_v_gain = 1; % Voltage gain
K_i_gain = 1; % Current gain
K_i_fltr = 1; % Current filter gain
G_d = 1; % Duty cycle transfer function

%% 2) Define s-domain variable and transfer functions
s = tf('s');
Zi = R + s*Lb;   % Impedance of the inductor

% Corrected Current Loop Transfer Function (Hp-i)
Hp_i = 3 * (1 / K_v_gain) * K_i_gain * K_i_fltr * G_d * (1 / Zi);

%% 3) Bode plot of the modeled open-loop gain
figure('Name','Modeled Open Loop Gain','NumberTitle','off');
bode(Hp_i, {2*pi*10, 2*pi*1e5});  % Bode plot from 10 Hz to 100 kHz
grid on;
title('Current Open-Loop Gain (Modeled)');

●

%% 4) Compare with measured data (if available)
% Replace with actual measured data if available
freq_meas     = [10, 100, 1e3, 10e3, 100e3];   % Hz (example)
mag_meas_dB   = [-5, -2,  0,   -3,   -10];     % dB (example)
phase_meas_deg= [ 0, -30, -60, -90, -120];     % deg (example)

% Extract the model’s magnitude and phase at the same measured frequencies
[mag_model, phase_model] = bode(Hp_i, 2*pi*freq_meas);
% Convert the magnitude (which is dimensionless) to dB
mag_model_dB = 20*log10(squeeze(mag_model));
phase_model_deg = squeeze(phase_model);

%% 5) Plot measured vs. modeled (Magnitude & Phase)
figure('Name','Open Loop Gain Comparison','NumberTitle','off');
subplot(2,1,1);  % Magnitude subplot
semilogx(freq_meas, mag_meas_dB, 'bo-', 'LineWidth',1.5, 'MarkerSize',6); 
hold on;
semilogx(freq_meas, mag_model_dB, 'rx--', 'LineWidth',1.5, 'MarkerSize',6);
grid on; xlabel('Frequency (Hz)'); ylabel('Magnitude (dB)');
legend('Measured','Modeled','Location','Best');
title('Current Open-Loop Gain: Magnitude');
subplot(2,1,2);  % Phase subplot
semilogx(freq_meas, phase_meas_deg, 'bo-', 'LineWidth',1.5, 'MarkerSize',6); 
hold on;
semilogx(freq_meas, phase_model_deg, 'rx--', 'LineWidth',1.5, 'MarkerSize',6);
grid on; xlabel('Frequency (Hz)'); ylabel('Phase (deg)');
legend('Measured','Modeled','Location','Best');
title('Current Open-Loop Gain: Phase');