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Three-phase bridge rectifier

Прочитайте:
  1. Consideration of a stage of switching of thyristors for a full-wave rectifier with centre tap and active - inductive load with infinite inductance
  2. Operation of a full-wave rectifier with a centre tap with an active load
  3. Operation of a full-wave rectifier with centre tap and active - inductive load and limitеd inductance
  4. Operation of a full-wave rectifier with centre tap and active - inductive load with infinite inductance
  5. Operation of single-phase half-wave rectifier with active load
  6. Operation of the half-wave rectifier with active - inductive load and limited inductance
  7. Operation of the half-wave rectifier with center tap and opposite-EMF and active-inductive load
  8. Operation of the half-wave rectifier with center tap with opposite- EMF and active load
  9. Operation of the half-wave rectifier with resistive-capacitive load
  10. Operation of the rectifier with opposite- EMF

Figure 1.35

 

1.11.1 Conditions: α=0; La=0; ra=0.

 

VS1, VS3, VS5 – a cathode group; VS4, VS6, VS2 – an anode group.

At each moment of time two thyristors are on-state - one of them is from the cathode group, another - from the anode group. This of thyristors from cathode group is conducting, which have highest EMF arranged to his anode. This of thyristor from anode group is conducting, which have lowest EMF arranged to his anode.

In result the potential of the common cathodes (“+” of the rectifier) varies according a top envelope of phase EMF, and potential of the common anodes (“-“ of the rectifier) varies according a bottom envelope of phase EMF.

The rectified voltage is equal to a difference of potentials of positive and negative poles of the rectifier and it is a difference of phase EMF of conducting thyristors. Frequency rate of pulsations of the rectified voltage with reference to frequency of a power line is equal to 6.

The direct component of rectified voltage

 

The peak-inverse voltage of thyristor

 

 

As the current of secondary winding of the transformer i2a has not a direct component so a primary current i1A is determined as

Let's demand to the equipment for Ld =∞:

Constant component of a thyristor current

RMS- value of a thyristor current

RMS value of a current of a secondary winding of the transformer

 

 

RMS value of a current of a primary winding of the transformer

 

Full power of windings S1, S2 and type power of transformer ST

 

Practically exceeding ST about power of rectified current Pd is only 5 %. Exceeding URM about Ud0 also is only 5 %. As frequency rate of pulsations of a curve of the rectified voltage is twice greater than for the three-phase rectifier with center tap, the level of the highest harmonics in it is less. Therefore the given circuit has the widest application. The primary winding may be connected in a triangle. Only the waveform of a linear current will be changed in this case.

 

 

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