design Boost Converter according to the specification.
peachkush
Purpose
The primary object of this experiment is:
a. To study the characteristics of a Boost Converter.
b. To design Boost Converter according to the specification.
c. To compare the calculated results with the experimental ones.
Equipment and Components
· MATLAB/Simulink with Simscape Electrical Library
PreLab
No prelab assignment for this experiment.
Simulation
Figure 1. Paste the Screen Shot of MATLAB/Simulink Model of Boost Converter
Laboratory procedures
Figure 1 shows MATLAB/Simulink Model for Boost Converter. Make sure to add test equipment (current and voltage measurement) as shown in figure for better learning experience during lab. Make sure Load is connected all the time while taking reading and observation.
MOSFET Ron = 50mOhm; MOSFET parallel capacitor to simulate junction cap = 0.1uF
Diode VF = 0.3V; Inductor Winding Resistance = 5mOhm; Capacitor ESR = 10mOhm
Problem Statement – Design Boost Converter for PV Module Maximum Power Point Tracker:
· Input Voltage VIN = 25V Nominal (with range from 20V to 30V)
· Output Voltage VOUT = 50V
· Maximum Output Power POUT = 100W to 250W
· IOUT = ?
· ROUT = ?
· Maximum Peak to Peak Output Ripple Voltage VO(PP) = 0.1% * VOUT = 50mV
· Switching Frequency FS = 100kHz
Calculate the following –
Load Calculations at VOUT = 50V 

POUT = 100W 
ROUT(MAX) 

ohm 

IOUT(MIN) 

A 
POUT = 250W 
ROUT(MIN) 

ohm 

IOUT(MAX) 

A 
· Value of Inductor so that the boost converter always remains in Continuous Conduction Mode (i.e. Inductor current value should always stay above 0A) under all operating conditions.
· Output Capacitor
Varying Input Voltage or Duty Cycle
a. Set the switching frequency at 100kHz on Pulse Generator and POUT = 250W.
b. Observe and make a copy of the output voltage.
Figure 2. Paste the Screen Shot of the output voltage
c. Record the average output voltage, the peak to peak output ripple voltage and the peak to peak inductor current at given input voltages in the table
VIN 
20 
25 
30 
V 
D (Calculated) 



% 
VOUT 



V 
∆VO(PP) 



VPP 
∆IL(PP) 



APP 
Is boost converter working as a programmable DC step up transformer? Yes or No?
Varying Switching Frequency
a. Set the duty ratio at 50% on Pulse Generator and POUT = 250W
b. Observe and copy a single screenshot of MOSFET Current, Diode Current, Inductor Current and Capacitor Current waveforms at 80kHz and 100kHz
Figure 4. Paste the single screen shot of iL, iFET, iD and iC waveform at 80KHz
Figure 5. Paste the single screen shot of iL, iFET, iD and iC waveform at 100KHz
c. Measure the peak to peak output ripple voltage and the peak to peak inductor ripple current at given frequencies in the table
Frequency 
80 KHz 
90 KHz 
100 KHz 
Unit 
∆VO(PP) 



VPP 
∆IL(PP) 



A(PP) 
Varying Load
a. Set the switching frequency at 100 kHz and duty ratio at 50% on the Pulse Generator
b. Set initial output load at POUT = 250W
c. Increase the load resistance and observe the inductor current waveform.
d. Keep increasing the load resistance, until the boost converter enters discontinuous current mode (DCM) operation. Note down the average inductor current value.
Is measured power at boundary is matching with theoretical one? If not then list the factors in practical model that are affecting boundary condition of Boost Converter.
e. Observe and copy a single screenshot of MOSFET Current, Diode Current, Inductor Current and Capacitor Current waveforms at that Boundary Condition.
Figure 6. Paste the single screen shot of iL, iFET, iD and iC waveform at Boundary
Determining Efficiency of Boost Converter
a. Set duty ratio at 50%. Set POUT = 250W. FSW = 80KHz
b. Measure the average output voltage VO.
c. Measure the average output current IO.
d. Measure the average input voltage VIN.
e. Measure the average input current IIN.
f. Repeat the same procedure from (b) to (e) for FSW = 100KHz
FSW = 100kHz 

VO (Measured) 

V 
IO (Measured) 

A 
PO = VO*IO 

W 
VIN (Measured) 

V 
IIN 

A 
PIN 

W 
Efficiency (100KHz) 

% 
FSW = 80KHz 

VO (Measured) 

V 
IO (Measured) (VO/RO) 

A 
PO = VO*IO 

W 
VIN (Measured) 

V 
IIN 

A 
PIN 

W 
Efficiency (80KHz) 

% 
Knowledge Evaluation:
Answer the following questions related to the above experiment. It is a free Response –
1. From the observation in section 5.4, how does boost converter efficiency changes with change in switching frequency? Explain in brief.
2. List the parameters of all components in the boost converter that affects overall converter efficiency.
3. Calculate the voltage VDS and current ID rating required for MOSFET in Boost Converter?
4. Calculate the voltage VF and current IF rating required for Diode in Boost Converter?
© – 2017 University of Houston, College of Technology ELET Labs
ELET 4126 48