Power Electronics

In a single-phase fully controlled bridge converter, what is the typical function of the thyristors used?

• To convert AC to AC

• To store electrical energy

• To convert AC to DC and control output voltage

• To generate the output frequency

For a single-phase fully controlled bridge converter, when the firing angle is 0°, the average output DC voltage is:

• Zero

• Equal to the RMS voltage of the AC supply

• Equal to the peak AC voltage

• Half of the RMS value of the AC supply

What happens to the output voltage in a single-phase fully controlled bridge converter when the firing angle is increased beyond 90°?

• The output voltage increases

• The output voltage decreases

• The output voltage remains unchanged

• The output voltage becomes zero

In a single-phase fully controlled bridge converter, the average output voltage across the load is controlled by:

• Changing the load resistance

• Varying the firing angle of the thyristors

• Changing the AC supply voltage

• Changing the frequency of the AC supply

For a single-phase fully controlled bridge converter, if the firing angle is 120°, what will be the average output voltage?

• Zero

• Half the peak voltage

• Full peak AC voltage

• Maximum negative value

In a single-phase fully controlled bridge converter, which of the following conditions is true for a purely inductive load?

• The output voltage is a pure DC signal

• The output voltage will exhibit large ripples

• The output voltage will be smooth with no ripple

• The output voltage will be zero

In a single-phase fully controlled bridge converter with resistive load, the output voltage is purely DC. Which waveform characterizes the output voltage?

• Triangular

• Sinusoidal

• Square

• Pulsating unidirectional DC

If the firing angle is increased in a single-phase fully controlled bridge converter, the average output voltage:

• Increases

• Decreases

• Remains constant

• Becomes higher than the input voltage

In a single-phase fully controlled bridge converter, which of the following waveforms is observed for the output voltage when the firing angle is 180°?

• Negative half-cycle of the input AC voltage

• Positive half-cycle of the input AC voltage

• Sinusoidal waveform

• A constant DC voltage equal to the RMS of the AC supply

The single-phase fully controlled bridge converter operates in:

• Both half-wave and full-wave rectification modes

• Only half-wave rectification mode

• Only full-wave rectification mode

• None of the above