Summary and Analysis of the Data from the Lab

Insert 2-3 paragraphs that use complete sentences to review and analyze what you have learned in the lab.
write it as a group

NORTHERN ARIZONA UNIVERSITYEE484: Experiment 3Boost Converter
Your Name, Your Lab Partner’s Name[Pick the date]

3.2. Preparing the Setup

The Rheostat reading is 19.97 Ohms

The wires had to be reversed in this lab, because the boost converter uses a right-left power flow.

3.3 Powering and Verifying the Circuit
Oscope
Duty Ratio: 10.24%
Frequency: 99.98 kHz

Vin= 10.0 V
Iavg= .57 A

Calculated
Vo=Vin/(1-D)
=10/.9
= 11.1111 V
Our actual output voltage is 10.8 V. This value is close to our expected voltage of 11.1 with only a minus .3 V difference.

Yes, the .3 V difference is probably attributed to the voltage drop due to typical resistance. It’s not a dramatic voltage drop, therefore this is reasonable.

Zoomed in V1 output voltage waveform:

Calculated I0
Io= Vo/R=  10.8/19.99 = 540.27 mA
Iin=Io/(1-D) = 540.27mA/(1-.1) = 600.3 mA
Our calculated Iin was .6003 A compared to our power supply reading of .58 A. With a . 02 A difference, this is within an acceptable range.

3.4 Measurements

3.4.1 Varying the Duty Ratio

Duty Ratio= 20.05%

Vo=Vin/(1-D)
=10/.8
= 12.5 V

Ideal Duty Ratio    Actual Duty Ratio    Calculated V0    Measured Vo    Calculated Iin    Measured Iin
10%    .101    11.111 V    10.8 V    .6003 A    .58 A
20%    .2005    12.5 V    12.0 V    .750 A    .72 A
30%    .299    14.265 V    13.7 V    .978 A    .94 A
40%    .403    16.75 V    16.0 V    1.34 A    1.31A
50%    .500    20.0 V    19.0 V    1.901 A    1.85 A

Yes, this would serve well as a boost converter. No, you should not operate it at a duty ratio of 95% because the values will be further distorted, as well as a general safety hazard.

3.4.2 Varying the Switching Frequency

For a boost converter, the inductor current is the same as the input current. To the left, negative side.

Peak to Peak and ripple values for CS5 waveform:

Measured Peak to peak = 184 mV
Measured Average = 944 mV

Measured Peak to peak IL = .368 A
Measured Average IL= 1.88 A

Calculated Peak to peak IL = .468 A
Calculated Average IL= 1.84 A

At 40 Hz

Measured Peak to peak = 464 mV
Measured Average =  931 mV

Measured Peak to peak IL = .928 A
Measured Average IL= 1.862 A

Calculated Peak to peak IL = 1.168 A
Calculated Average IL= 1.81 A

At a frequency of 100 kHz the values were slightly more accurate. Yes, this matches what we expected. Lowering Fs raises Ts, which in turn raises the peak to peak current. By the equation delata iL = (1/L)*Vin*D*Ts.

3.4.3 Additional Waveforms

The above image looks like a clean square wave as expected. The MOSFET apprears on when the PWM is low and MOSFET is off when the PWM is high.

The MOSFET is on when PWM signal is low. The MOSFET should block about 20 V when it is turned off.

Data to calculate

Summary and Analysis of the Data from the Lab

Insert 2-3 paragraphs that use complete sentences to review and analyze what you have learned in the lab.

Power Electronics Experiment 3
Boost Converter
3.1 Objective
The objective of this experiment is to study the characteristics of a boost converter, and to
compare the theoretical predictions of a boost converter’s behavior with experimental results.
The circuit will be operated under continuous current mode (CCM) and open loop (no feedback)
conditions. This activity was derived from the power electronics laboratory experiments
developed and distributed by the University of Minnesota (UMN).
3.2 Preparing the Setup
Turn on the oscilloscope and collect a set of power electronics lab equipment from the cabinet
including a Phillips screwdriver, which is needed to reconfigure the board into a boost converter.
The team member who is setting up the power-pole board should use the grounding wrist strap.
Change the jumper wires on the power-pole board (which are red in the pictures) as shown in
Figures 3.1 through 3.3, so that the upper diode and the lower MOSF ET are connected through
their access screw terminals, and the node between these devices is connected to the inductor
board through its screw terminal. (This is different than previous experiments, where we used the
upper MOSFET and the lower diode.) In addition:
Ensure that the correct magnetics board (which contains the inductor) is being used.
Set all of the toggles in the white switch bank to the down position, so that the PWM
control signals will be applied to the lower MOSFET.
Set the rheostat to 20 Q, and record the DMM measurement of the rheostat’s resistance.
Connect the rheostat on the left side of the board this time, across the terminals V1+ and
COM.
Connect the 112 V signal supply. Ensure that the extra cable section, which rearranges
the pin configuration, is well connected to the original cable. The associated signal
supply switch (S90) should remain OFF for now.
Set the test bench’s higher-power DC power supply to zero volts and then connect it to
the right side of the power-pole board, across the terminals V2+ and COM. (Remember
that the cables should connect to the ‘+’ and ‘-‘ ports of the DC power supply.) Do not
increase the voltage yet. In your report, explain why the input voltage and output load
connections had to be reversed for the boost converter, as compared to the buck
converter configuration. The circuit diagram in Figure 3.4 and the location of the boost
converter’s primary components on the power-pole board may aid your understanding
and explanation.
Double-check that no cables are draped across the power-pole board and that no cables are
touching the back of the rheostat. Follow the separately provided instructions to calibrate the
oscope, and remember that the probes must be removed during this procedure.