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Three-Phase Bridge Rectifier by Jv24D2A

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									Three-Phase Power
                  Definitions

• 4 wires
  – 3 “active” phases, A, B, C
  – 1 “ground”, or “neutral”
• Color Code
  – Phase A     Red
  – Phase B     Black
  – Phase C     Blue
  – Neutral     White or Gray
Phasor Diagram
Delta-Connected Sources




        VLINE = V
Phasor Diagram, VAB as reference
Look at the Currents




      I = ILINE / 3
Y-Connected Sources
Phasor Diagram with A as reference
Complete Phasor Diagram




       VLINE = 3V
Look at the Currents




      I = ILINE
Three-Phase Bridge Rectifier
Conduction Sequence
Average Output Voltage, Vdc




              T
          1
    Vdc 
          T    f (t )dt
              0
                  

           2 6
    Vdc      3Vm cos td (t )
          2 0
           6
          3 3
    Vdc      Vm  1.654Vm
          
       rms Output Voltage
                                       1
                                    2

         2    6
                                   
              3Vm cos td (t ) 
                    2   2
Vrms
          2
              0                   
         6                        
                     1
         3 9 3     2
Vrms    
          2 4   Vm
                 
Vrms    1.6554Vm
       Diode Currents

     3Vm
Im       peak
     R
                                   1
          
                                 2

       4                      
           6
Ir        I m cos td (t ) 
               2    2

        2 0
      
                              
                               
I r  0.5518I m
Transformer Secondary Current
                                     1
             
                                   2

       8                        
             6
 Is         I m cos td (t ) 
                 2    2

        2
      
      
             0
                                 
                                 
                                    1
           2  1   2           2
 I s  I m    sin           
             6 2   6        
 I s  0.7804 I m
        Instantaneous Output Voltage



                        2            2
v0 (t )  0.9549Vm (1  cos(6t )      cos(12t )  ...
                       35           143

								
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