Benha University Applications of Power Electronics
Faculty of Engineering at Shoubra 2nd Semester, AY 2024-2025
Department of Electrical Engineering 4th year, EPE 448
Design of Rectifier Output Filters
1. Determine the performance parameters of single-phase Full-wave
uncontrolled rectifier circuit feeding resistive load (R).
Hint: Find; efficiency, Form factor (FF), Ripple factor (RF), transformer
utilization factor (TUF), PIV of D4, crest factor(CF) of the input current, and
the supply power factor.
2. A single-phase diode bridge rectifier is supplied from a 220-V, 50-Hz AC
source. If the load resistance is 100 Ω and the load inductance is 0.1 H,
determine:
(a) The ripple factor (RF) of the load current (without using an inductive DC
filter, Lf), using a more accurate method until the fourth harmonic order.
Compare the result with the approximate method.
(b) The value of the additional series inductance (Lf) that limits %RF of the
load current to be 5%.
3. A single-phase diode bridge rectifier is supplied from a 220-V, 50-Hz AC
source. If the load resistance is 50 Ω, Use C-filter, determine:
(a) The ripple factor (RF) of the load voltage, using a more accurate method
until the fifth harmonic order. Compare the result with the approximate
method.
(b) The value of the filter capacitor (Cf) that limits RF of the load voltage to be
5%.
4. A single-phase diode bridge rectifier is supplied from a 220-V, 50-Hz AC
source and feeds a load resistance of 40 Ω.
(a) Use an LC-filter to reduce the %RF of the rectifier output voltage to be 10%.
(Assume filter capacitor from Table(1).
(b) Calculate the cut-off frequency of the selected filter, Comment on the result
5. Referring to problem (4), find the new value of %RF if:
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Benha University Applications of Power Electronics
Faculty of Engineering at Shoubra 2nd Semester, AY 2024-2025
Department of Electrical Engineering 4th year, EPE 448
(a) The filter capacitance value is increased 20% and the filter inductance
value is reduced 10%.
(b) The filter capacitance is decreased to 20% and the filter inductance is
increased 10%.
(c) Comment on the results of (a) and (b).
(d) Draw the relation between %RF and the load resistance if the load
resistance is changed from 10: 100 Ω.
6. Referring to problem (4), if the load is inductive (R=25 Ω, L=10 mH),
determine the values of the filter inductance and filter capacitance so that the
ripple factor of the rectifier output voltage is 5%.
7. A single-phase diode bridge rectifier is supplied from a 220-V, 50-Hz AC
source and feeds a load resistance of 50 Ω.
(a) Calculate the %RF.
(b) Use an LC-filter to reduce the RF of the rectifier output voltage in (a) to
be 10%. (Select the appropriate filter capacitor from Table1 neglect the
resistance of the selected capacitor)
(c) If the load resistance is doubled, the new value of the % RF “decreased,
increased, maintain the same”. Comment on your answer.
Table (1)
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