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EE 410 – Power Electronics Laboratory
Fall 2010
Dr. Dale Dolan
Experiment #1 – Diode Rectifier Circuits
Group #3
James Tuccillo, Scott Carey, Rene Canedo
10/15/2010
EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
Diode Rectifier Circuits Laboratory – A Power Electronics Laboratory Experiment
Purpose: This lab seeks to illustrate the fundamental operation of uncontrolled rectifier
circuits. The waveforms associated with these circuits are visualized using simulation
and experimentation. The circuit operating values obtained using theoretical equations
are challenged through simulation and experimentation.
1. LIST OF EQUIPMENT







PC Computer with ORCAD PSPICE Schematic Capture and Simulation
Fluke 37 Digital Multimeter
Fluke Power Scopemeter 97
GWinstek GPM 8212 AC Power Meter
Power Diode Module
Capacitor and Resistor
Miscellaneous Connection Leads
2. CIRCUIT DIAGRAMS
Figure 1 - Single-Phase Full-wave Rectifier With Resistive Load
Figure 2 - Three-Phase Full-wave Rectifier with Resistive Load
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
3. PROCEDURE
3.1 Computer Simulation Procedure
In all simulations, use an ac source voltage whose line to neutral voltage Vs = 100 Vac-rms at 60
Hz, a resistive load of R=150ohm, and for step g) a capacitor C = 4,700 uF.
a. Simulate the circuits shown in Figures 1 and 2 on one schematic page. Use the ideal
diode Dbreak found in the “Breakout” library.
b. Set the simulation time to 500ms. Run the simulation.
c. Obtain and include in your report plots of output voltage waveforms by copying and
pasting the plots into Word (instead of printing them out). Ask the instructor if you do not
know how to do this.
d. For both circuits, use the AVG() and RMS() functions in the Probe Window to obtain the
averages and RMS values of the outputs, and their ratios (AVG/Total RMS). Do not print
out or include these plots in your report. Compare the results to those obtained in the
calculation section.
e. For both circuits, determine the input power factor.
f. For both circuits, obtain input current and input voltage waveforms. Include (copy and
paste) only the current waveforms in your report.
g. Add a 7,400uF capacitor in parallel to the resistor in each circuit. Also, to help with the
convergence problem, insert a 10m resistor in series with the capacitor.
h. Repeat part b) through f), but change the simulation time to 20 seconds.
i. By comparing the input and output waveforms of Resistive Load with Resistive/Capacitor
load, what conclusion can you draw as to the effect of adding a capacitor at the load?
3.2 Hardware Simulation Procedure
Background:
In this part of the lab, you will build the rectifier circuits that you simulated in the previous part by
using a Power Diode module shown in Figure 3. Since this experiment uses relatively high
power circuits, make sure that you have the instructor check your circuit before turning on
the power. Also, make sure to turn off the bench power before making any changes to your
circuit.
Figure 3 - Power Diode Module
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
Preliminaries
a. Check the Power Diode Module
 The Power Diode Module consists of three dual-diode packages. Each package has
two diodes whose internal connection diagram is shown on one side of each diode
pack. Look for this diagram.
 Find the datasheet for the diode on the Internet. From the datasheet, find the current
and voltage ratings of the diode.
 Perform a quick visual inspection on the 3A fuses located in front of each diode
package. Let the instructor know if any of the fuses are missing.
b. Use either a scopemeter of a multimeter in conjunction with the variac (located
underneath each bench) to obtain an AC input power of 100Vrms line to neutral of phase
voltage.
CAUTION:
When using the scopemeter, do NOT connect one channel to output voltage
and the other channel to the input voltage.
Single-Phase Full-wave Rectifier
c. Build a single-phase full-wave rectifier with 150 resistive load with an AC power meter
connected at the input side. On the output side, connect an ammeter (using a
multimeter) and a voltmeter using a scopemeter.
d. Using the scopemeter with DC coupling, sketch the output voltage (include the scope
settings, i.e. volts/div, sec/div).
 How does the waveform compare to the simulated result?
 Count the number of pulses on the output voltage per one period of the input
voltage.
 Measure the peak to peak ripple voltage on the output voltage.
 Determine the ratio (Average/Total RMS) of output voltage. How does it compare
with calculation and simulation results?
e. Using the Current Probe Amplifier + Oscilloscope, obtain the input current waveform and
include it in your lab report.
f. Determine the efficiency of the circuit.
g. While the power is off, turn the variac all the way down to zero volts and add a 7400uF
capacitor in parallel with the resistive load. Turn the power on and turn the variac
gradually to 100Vrms.
h. Using the scopemeter with DC coupling, sketch the output voltage (including the scope
settings, i.e. volts/div, sec/div). How does it compare to the results obtained in d)?
i. Using the Current Probe Amplifier + Oscilloscope, obtain the input current waveform and
include it in your lab report. How does it compare to the results obtained in e) Explain
how the input current waveform changes from what you observed in e).
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
Three-Phase Full-Wave Rectifier
j.
Build a three-phase full-wave rectifier with 150 resistive load. Connect the input side
(which is the secondary side of the bench transformer) in an ungrounded ‘Y’ connection.
On the output side, connect an ammeter (using the multimeter) and a voltmeter, using
the scopemeter.
k. Using the scopemeter with DC coupling, sketch the output voltage (include the scope
settings, i.e. volts/div, sec/div).
 How does the waveform compare to the simulated result?
 Count the number of pulses on the output voltage per one period of the input
voltage.
 Measure the peak to peak ripple voltage on the output voltage.
 Determine the ratio (Average/Total RMS) of output voltage. How does it compare
with calculation and simulation results?
l. Using the Current Probe Amplifier + Oscilloscope, obtain the input current waveform and
include it in your lab report.
4. CALCULATIONS
4.1 Prelab Calculations
1.1 For the single-phase full-wave rectifier, calculate:
a. The average and total rms values of the output voltage when the AC input is
100 Vrms.
VR 
2Vm


2( 2)(100)

 90.03 V
V
100( 2)
V˜ R m 
 100 V
2
2

b. The ratio of (Average/Total RMS)

Average 90.03 V

 90.03%
TotalRMS
100 V
c. The input power factor assuming ideal diodes, and Rload = 150

V˜o 2 100 2

 66.7 W
R
150
V˜ 100 V
I˜s  I˜o  o 
 0.67 A
R 150 
P
P
66.7 W
pf in  in  ˜ out˜ 
1
S in V s I s 100 V 0.667 A
P in  Pout 

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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
4.1 Prelab Calculations (Cont.)
1.2 For the three-phase full-wave rectifier, calculate:
a. The average and total rms values of the output voltage when the phase
voltage (line to neutral) AC input is 100 Vac-rms.
VR 
3Vm LL


3( 2 3100V )

 234 V
V˜R  0.956 VmLL  0.956 2 3 100V  234 V

b. The ratio of (average/total rms).

Average 234 V

 100%
TotalRMS 234 V
c. The input power factor assuming ideal diodes, and Rload = 150 .

pf in 
Pinout V˜out I˜out 0.956 2 3V
 ˜ ˜ 
 0.956
Sin
3VLN I
2
3
 V
3
1.3
 Which rectifier circuit do you suggest has better dc output performance? Better AC
input performance?
The 3- rectifier circuit has better DC output performance due to the increased
ripple frequency. By increasing the ripple frequency, filtering becomes easier as well as
the average DC value increases.
The 1- rectifier circuit has better AC input performance due to its processing of a
single component of input current. Since the source is delivering power on both the
positive and negative half cycles, the source has a zero distortion power factor. This is
seen in the power factor calculation above in question 1.1.
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
5. DATA AND OBSERVATIONS
Resistive Load
Theoretical
Simulated
100
98.5
97.6
85.6
DNR
90.03
88.4
86.9
69.5
DNR
1
0.991
NA
0.072
NA
Vrms (V)
234.0
234.4
269.7
211.65
NA
Vdc-rms (V)
234.0
232.2
267.0
210.27
NA
pf
0.956
0.93
NA
0.298
NA
Vrms (V)
Vdc-rms (V)
Single Phase
Three Phase
With Capacitor
pf
Experimental
Simulated
Experimental
Table 1: Output Voltage Summary for Theoretical Calculations, Simulated, and Experimental Results
Resistive Load
With Capacitor
Theoretical
Simulated
Experimental
Simulated
Experimental
Single Phase
Vdc-rms/Vrms
0.903
0.897
.890
1.000
DNR
Three Phase
Vdc-rms/Vrms
1.000
0.990
0.989
1.000
NA
Table 2: Calculated Efficiencies for Output Voltages of Table 1
# of pulses
Peak-topeak ripple
Single-Phase
Full Wave
Rectifier
2
Three-Phase
Full-Wave
Rectifier
6
146 (1.7 w/cap)
38
Table 3: Experimental Results for Output Voltage Pulses Per Single Input Voltage Period
The efficiency of the single-phase rectifier as asked in procedure step f) is the following:
%Efficiency 
Pout 60.14W

 94.9%
Pin 63.40W

DNR = Did Not Record Quantitatively
NA = Non-Applicable or Not Procedurally Called for Measurement
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Experiment 1 – Diode Rectifier Circuits
6. GRAPHS
6.1 Simulation Graphs
150V
100V
50V
SEL>>
0V
V(D1:2,D3:1)
4
200V
0V
-200V
20.0ms
V(V1:+,0)
30.0ms
40.0ms
50.0ms
60.0ms
70.0ms
80.0ms
90.0ms
100.0ms
109.2ms
Time
Graph 1: Simulate Voltage Waveforms for Single-phase Full-wave rectifier with resistive load.
Green (Vout) Red (Vin)
1.0A
0.5A
0A
-I(R1)
1.0A
0A
SEL>>
-1.0A
19.90s
I(V1)
19.91s
19.92s
19.93s
19.94s
19.95s
19.96s
19.97s
19.98s
19.99s
20.00s
Time
Graph 2: Simulated Current Waveforms for Single-phase Full-wave rectifier with resistive load.
Top Graph (Iout) Bottom (Iin)
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
250V
225V
SEL>>
200V
V(D6:2,R2:1)
100V
0V
-100V
-150V
141.2ms
V(D8:2)
150.0ms
V(D9:2)
V(D7:1)
160.0ms
170.0ms
180.0ms
190.0ms
198.7ms
Time
Graph 3: Simulated Voltage Waveforms for 3- Full-wave rectifier with resistive load no cap.
Top (Vout) Bottom (Vin)
1.7A
1.6A
1.5A
1.4A
-I(R2)
2.0A
0A
SEL>>
-2.0A
200ms
I(V2)
210ms
220ms
230ms
240ms
250ms
260ms
270ms
280ms
290ms
Time
Graph 4: Simulated Current Waveforms for 3- Full-wave rectifier with resistive load no cap.
Top Graph (Iout) Bottom (Iin)
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300ms
EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
165
160
150
140
SEL>>
135
V(D1:2,R1:1)
- I(C2)+139
200V
0V
-200V
19.90s
19.91s
V(V1:+,0)
19.92s
19.93s
19.94s
19.95s
19.96s
19.97s
19.98s
19.99s
20.00s
Time
Graph 5: Simulated Voltage Waveforms for 3- Full-wave rectifier with cap in parallel with resistor.
Top (Green=Output Voltage Red=Icap) Bottom (Vin)
40A
0A
SEL>>
-40A
I(V1)
932mA
928mA
924mA
920mA
19.90s
-I(R1)
19.91s
19.92s
19.93s
19.94s
19.95s
19.96s
19.97s
19.98s
19.99s
Time
Graph 6: Simulated Current Waveforms for 3- Full-wave rectifier with capacitor in parallel with resistor.
Bottom (Iout) Top (Iin)
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20.00s
EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
260
250
240
SEL>>
230
V(D7:2,D8:1)
- I(C1)+234
200V
0V
-200V
19.90s
V(D8:2)
19.91s
V(D9:2)
19.92s
V(D7:1)
19.93s
19.94s
19.95s
19.96s
19.97s
19.98s
19.99s
20.00s
Time
Graph 7: Simulated Voltage Waveforms for 3- Full-wave rectifier with cap in parallel with resistor.
Top (Green=Output Voltage Red=Icap) Bottom (Vin)
40A
0A
-40A
- I(V2)
-1.616A
-1.618A
-1.620A
SEL>>
-1.622A
19.90s
I(R2)
19.91s
19.92s
19.93s
19.94s
19.95s
19.96s
19.97s
19.98s
19.99s
20.00s
Time
Graph 8: Simulated Current Waveforms for 3- Full-wave rectifier with capacitor in parallel with resistor.
Bottom (Iout) Top (Iin)
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
6.2 Experimental Graphs
Graph 9: Experimental Input Current for Single-Phase Full-wave rectifier with resistive load (0.5A/(10mV/div))
Graph 10: Experimental Input Current for Single-Phase Full-wave rectifier with parallel capacitor and resistor
(2A/(10mV/div))
Graph 11: Experimental Input Current for Three-Phase Full-wave rectifier with resistive load (0.5A/(10mV/div)
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
Graphs 12 & 13: Output Voltage of Single-Phase Full-Wave Rectifier Circuit.
Without Capacitor (Left) With Capacitor (Right)
Graph 14: Output Voltage of Three-Phase Rectifier Circuit. Note that there are 6 pulses for each
period of the output waveform signal.
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
7. DISCUSSION
Single-Phase Full-Wave Rectifier
The single-phase waveform with purely resistive load shown in Graph 9 looks very similar to the
simulated result shown in Graph 1. Notice how there are two “pulses” for each input voltage
period. Also, both of these current waveform graphs appear to have a pure sinusoidal form. This
is due to the unity power factor operation of the single phase full-wave bridge rectifier circuit.
When the capacitor is added to the circuit as shown in Graph 10, the input current becomes
more spiked and less sinusoidal. This is because the conduction time of the diode decreases
the time where the diode current is following the voltage waveform as well as the effects of the
capacitor. As the waveform becomes more peaked and less sinusoidal, the power factor begins
to stray from unity. The output voltage waveform, Graph 13, shows how the output capacitor
“holds” the output voltage during the off-cycles and linearly discharges during that period.
During the positive half cycle, or “on” state, the capacitor is charged to the maximum value of
the input voltage minus the diode forward conduction drop.
Three-Phase Full-Wave Rectifier
For the three-phase full-wave rectifier circuit it can be seen that the input current waveform in
Graph 11 looks very similar to the simulated result in Graph 4. The non-sinusoidal nature of this
graph, as indicated by a small dip in the middle of the conducting period, shows that this circuit
has contributed a harmonic to the input current signal. The creation of this harmonic is due to
the switching of the input current from a conducting to an off state almost instantaneously. From
the output voltage waveform shown in Graph 14, it is seen that the output voltage has 6 pulses
per one period of input voltage. It is also shown that the output voltage following the three-phase
line-to-line voltage of the transposition of the three voltage phasors.
8. CONCLUSION
Altogether, this lab illustrated the operation and behavior of uncontrolled diode rectifier circuits
namely, the single-phase full wave rectifier and the 6-pulse three-phase full wave rectifier circuit.
Through theoretical calculations the team was able to predict the circuit operating values and
roughly sketch the types of expected waveforms. While this analytical method proved to be
useful in establishing the mathematical principles, it was the simulation that truly gave the group
the visual grasp of the circuit’s operational behavior. Finally, through experimentation the circuit
was realized and implemented using real electronic circuit components. By implementing these
circuits in laboratory, we were able to confirm the design and operation of the circuits from a
high level understanding to a device performance level as seen in the non-ideal characteristics
of the diodes (dead time and forward voltage drop).
This lab also let us accomplish prerequisite learning objectives such as reviewing our
understanding of three-phase power concepts and the use of current and voltage probes for
oscilloscope analysis. Another important understanding we gained was that of electrical safety.
By working with capacitors and high AC voltage, we learned the proper attitudes and respect to
have when dealing with >120V AC.
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EE 410 – Power Electronics Laboratory
Experiment 1 – Diode Rectifier Circuits
9. SIGNATURES
_______________________
Name
________________________
Signature
________________________
Date
_______________________
Name
________________________
Signature
________________________
Date
_______________________
Name
_______________________
Signature
_________________________
Date
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