Power Electronics Lecture (7)

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Power ElectronicsLecture (7)

• Prof. Mohammed Zeki Khedher
• Department of Electrical Engineering
• University of Jordan

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Single-Phase Full-Wave Diode Rectifier
Center-Tap Diode Rectifier
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PIV of each diode
Example 3. The rectifier in Fig.2.8 has a purely
resistive load of R Determine (a) The efficiency,
(b) Form factor (c) Ripple factor (d) TUF (e)
Peak inverse voltage (PIV) of diode D1 and(f)
Crest factor of transformer secondary current.
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The PIV is
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Single-Phase Full Bridge Diode Rectifier With
Resistive Load
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Example 4 single-phase diode bridge rectfier has
a purely resistive load of R15 ohms and, VS300
sin 314 t and unity transformer ratio. Determine
(a) The efficiency, (b) Form factor, (c) Ripple
factor, (d) The peak inverse voltage, (PIV) of
each diode, , and, (e) Input power factor.
The PIV300V
Input power factor
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Comparision between Single Phase Rectifiers

• Half wave
  Full wave Fullwave
• 
  center-tap
  bridge
• Peak repetitive reverse voltage VRRM 3.14Vdc
  3.14 Vdc 1.57 Vdc
• Rms input voltage per transformer leg Vs 2.22
  Vdc 1.11 Vdc 1.11 Vdc
• Diode average current IF.AV. 1.00 Idc 0.50
  Idc 0.50 Idc
• Diode rms current IF.RMS.
  1.57 Idc 0.785 Idc 0.785 Idc
• Form factor of diode current IF.RMS. 1.57
  1.57 1.57
• Rectification ratio
  0.405 0.81 0.81
• Form factor
  1.57 1.11 1.11
• Ripple factor
  1.21 0.482 0.482
• Transformer rating primary VA
  2.69 Pdc 1.23 Pdc 1.23 Pdc
• Transformer rating secondary VA
  3.49 Pdc 1.75 Pdc 1.23 Pdc
• Output ripple frequency fr
  1 fi 2 fi 2 fi

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Multi-phase Rectifier
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Three-Phase Half Wave Rectifier
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ThePIV of the diodes is
Example A 3-phase star rectifier is operated
from 460 V 50 Hz supply at secondary side and the
load ? resistance is R20. If the source
inductance is negligible, determine (a)
Rectification efficiency, (b) Form factor (c)
Ripple factor (d) Peak inverse voltage (PIV) of
each diode.
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The PIV
Vm650.54V
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Three-Phase Full Wave Rectifier With Resistive
Load
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Example 10 The 3-phase bridge rectifier is
operated from 460 V 50 Hz supply and the load
resistance is R20ohms. If the source inductance
is negligible, determine (a) The efficiency, (b)
Form factor (c) Ripple factor (d) Peak inverse
voltage (PIV) of each diode .
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The PIV
Vm650.54V
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Performance
Single phase rectifier 3 phase
rectifier
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3-phase bridge rectifier with RL load
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Condition for continuous load current