The circuit will be operated under continuous current mode (CCM) and open-loop conditions (no feedback).

Build the circuit in Matlab- Simulink /Multisim

2.2.1. The output voltage should vary in the range of 10-90% of an input voltage, The switching frequency varies between 40kHz and 100KHz. The PWM circuit is used to generate the required switching frequency. The critical resistance has to be determined so that the circuit operates at the boundary between the continues and discontinuous conduction mode when the output voltage is set to 12V. The MOSFET and the diode should be selected to meet the circuit requirements

Adjust the duty ratio to 50%.

Adjust the switching frequency to 100kHz.

Apply input voltage Vd of 24 volts.

2.3 Measurement and Waveforms

Take the following measurements, 2.3.1
Varying Duty Ratio
Set the duty ratio at 50%, switching frequency at 100 kHz and RL= 10Ω.

Observe and make a copy of the output voltage and voltage across the diode.

Vary the duty ratio from 10 % to 90 % (in steps of 10%).

Measure the average output voltage for the corresponding duty ratio.

Calculate the theoretical average output voltage for the corresponding duty ratios.

2.3.2 Varying Switching Frequency

Set the duty ratio to 50 %.

Measure the peak-peak output ripple voltage and the peak-peak ripple in inductor current.

Repeat the above procedure for different switching frequencies (40 kHz , 60 kHz, 80 kHz). Make sure that output voltage is maintained at 12V.

Observe and make a copy of the inductor current and capacitor current waveforms at 40kHz and at 100kHz.

2.3.3
Varying Load

Set the switching frequency at 100kHz and duty ratio at 50%.

Set the load resistance RL=10Ω.

Increase the load resistance and observe the inductor current waveform.

Keep increasing the load resistance, until the buck converter enters discontinuous current mode operation. Note down the average inductor current value and make a copy of the inductor current waveform when the converter starts entering discontinuous current mode of operation.

2.3.4 Determining Efficiency

Determine the efficiency of the buck converter at frequencies of 40 kHz and 100 kHz.

Set duty ratio at 50%.

Set load resistance RL=10Ω.

Measure the average output voltage Vo.

Measure the average output current Io.

Measure the average input voltage Vd.

Measure the average input current Id.

Calculate the efficiency of the buck converter for the above two frequencies.

***The lab report should have a brief abstract detailing what has been done in the experiment. The remaining part of the report should consist of the information asked below along with any discussion you feel is necessary.***

Attach a graph output voltage (Vo) versus duty ratio using data obtained in section

2.3.1. Also plot the theoretically calculated results on the same graph. Compare the two plots and comment about how the buck converter works as a variable dc step down transformer. Enclose output voltage & voltage across diode waveforms for duty ratio 50%
.

Attach a copy of the inductor current and the capacitor current waveforms obtained in section 2.3.2. Explain the relation between the two currents. Comment on the ripple in the inductor current for the two frequencies.

Plot the peak-peak ripple in the output voltage versus switching frequency using data obtained in section 2.3.2. Plot the theoretical results on the same graph. Compare the two plots. Comment on why you were asked to maintain the average output voltage constant.

Attach a copy of the inductor current waveforms obtained in section 2.3.3. Compare the theoretically calculated Rcrit with the observed value.

Comment on the difference in efficiency results obtained for two switching frequencies.

### Must mention every step/code of Matlab/mulsim software for this lab report separately ###

please mention every singular step of

how to draw/what codes is used in circuit making, simulation process, and how to view the graph in Matlab/multisim.

Answer rating: 100% (QA)

Abstract This lab report focuses on the design and operation of a buck converter circuit using MatlabMultisim The buck converter is used to vary the output voltage in the range of 1090 of an input vol... View the full answer