1-phase diode rectifiers
Post on 08-Apr-2018
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1-Phase DiodeRectifiers
Diode Rectifier Block Diagram
Uncontrolled utility interface (ac to dc)
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S. Rajakaruna 2009 Power Electronics 3
A Simple Circuit
Resistive load
S. Rajakaruna 2009 Power Electronics 4
A Simple Circuit ( R-L Load)
Current continues to flows for a while even after the inputvoltage has gone negative
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S. Rajakaruna 2009 Power Electronics 5
A Simple Circuit (Load has a dc back-emf)
Current begins to flow when the input voltage exceeds the dc back-emf
Current continues to flows for a while even after the input voltage hasgone below the dc back-emf
S. Rajakaruna 2009 Power Electronics 6
Single-Phase Diode Rectifier Bridge
Large capacitor at the dc output for filtering and energystorage
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S. Rajakaruna 2009 Power Electronics 7
Diode-Rectifier Bridge Analysis
Two simple (idealized) cases to begin with
S. Rajakaruna 2009 Power Electronics 8
Redrawing Diode-Rectifier Bridge
Two groups, each with two diodes
Only one diode from each group will conduct.
In the top group, the diode with its anode connected to the highestpositive potential will conduct.
In the bottom group, the diode with its cathode connected to thehighest negative potential will conduct.
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S. Rajakaruna 2009 Power Electronics 9
When V s>0, D 1 and D 2 conduct. When Vs
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