- Buck Numerical Model Problem 100 Pts Given That An Abrupt Change In The Input Voltage Of The Underdamped Rlc Circuit 1 (101.58 KiB) Viewed 39 times
clear;clc;
s=tf('s');
RL = 10;
C = 220e-6;
L = 10e-6;
Rs = 100e-3;
Zout = RL/(1+(s*RL*C));
H_s = Zout/(Zout + Rs + L*s);
I_s = 1/(Zout + Rs + L*s);
T = 20e-6;
f = 1/T;
D = 25;
t=0:1e-7:1200e-6;
Vin = 24+24*square(2*pi*5e4*t,D);
Vout = lsim(H_s,Vin,t);
IL = lsim(I_s,Vin,t);
figure(1);
subplot(2,1,1)
plot(t*1e6,Vin)
xlabel('Time (us)')
ylabel('Input (V)');
title('Input square wave with 25% duty ratio');
grid minor;
subplot(2,1,2)
plot(t*1e6,Vout)
xlabel('Time (us)')
ylabel('Output (V)');
title('Output voltage response');
grid minor;
figure(2);
subplot(2,1,1)
plot(t*1e6,Vin)
xlabel('Time (us)')
ylabel('Input (V)');
title('Input square wave with 25% duty ratio');
grid minor;
subplot(2,1,2);
plot(t*1e6,IL);
xlabel('Time (us)')
ylabel('Current (A)');
title('Inductor current');
grid minor;
I need to answer the following questions
(c) At steady-state, the inductor current has negative values.
What is the inductance value that circumvents the inductor current
from going below zero for any duty cycle? Using the MATLAB script
in part (a) simulate the inductor current at a duty cycle D of 0.1,
0.2, 0.3, ..., 0.9 using this inductance value and show a plot that
proves the inductor current does not go below zero at the
aforementioned duty cycles.
(d) Using the script in part (a) and the inductance value in
part (c), compare the MATLAB simulated average value of the
steady-state output voltage of the buck converter versus the
theoretical model. Provide a plot that contrasts the MATLAB script
simulation results as ‘dots’ versus the model as ‘solid line’ at a
duty cycle D of 0.1, 0.2, 0.3, ..., 0.9.
(e) Using the script in part (a) and the inductance value in
part (c), compare the MATLAB simulated peak-to-peak value of the
inductor current at steady-state versus its theoretical model that
we studied in class. Provide a plot that contrasts the MATLAB
script simulation results as ‘dots’ versus the model as ‘solid
line’ at a duty cycle D of 0.1, 0.2, 0.3, ..., 0.9.
(f) At a duty cycle of 0.5, simulate the inductor current and
the output voltage using the script in part (a) and the inductance
in (c) with an Ron of 0.1 Ω and 10 Ω. What is the
waveform of the inductor current using both Ron values?
Is the value of the output voltage at steady-state equal to the
duty cycle in each case? why?
Buck Numerical Model Problem (100 pts): Given that an abrupt change in the input voltage of the underdamped RLC circuit in the figure below results in an inductor current and an output voltage that are given by: R1 L1 VIN VOUT 100m 10μ VSW C1 M R2 220μ 10 PULSE(O 48 0 1p 1p 5u 20u) .tran 1200u di L =Vin- i,Ron – V out dt L dy out V out C L dt R