Power Electronics - 2

A single-phase full-bridge diode rectifier feeds a resistive load of 50 Ω from a 200V,

50Hz single-phase AC supply. If the diodes are ideal, then the active power drawn by the

load is ………... (round of nearest integer)

• 200

• 1600

• 500

• 800

RC-IGCTs are known as

• Symmetrical IGTCs can be fabricated with reverse conducting

  diode in the same package.

• Symmetrical IGCTs can be fabricated with reverse conducting SCR in the same

  package.

• Asymmetrical IGCTs can be fabricated with high leakage inductance in the same

  package.

• Asymmetrical IGCTs can be fabricated with reverse conducting diode in the

  same package

dv/dt protection is provided to the SCR by

• dv/dt protection is provided to the SCR by

• connecting an inductor in series with the load

• connecting a capacitor & resister in parallel with the device

• connecting an inductor & resister in parallel with the device

An SCR has a half-cycle surge current rating of 3000 A for 50 Hz. Calculate its

one-cycle surge current rating

• 3121.32 A

• 2121.32 A

• 3131.32 A

• 2131.32 A

Choose the correct statement

• MOSFET has a positive temperature co-efficient

• MOSFET has a high gate circuit impedance

• MOSFET is a voltage controlled device

• All of the mentioned

A single-pulse transformer with secondary voltage of 230 V, 50 Hz, delivers power

to bulb of R = 10 Ω through a half-wave- controlled rectifier circuit. For α = 60°

and output AC power of 2127 Watts, find the rectification efficiency

• 98.6 %

• 42 %

• 28 %

• 19 %

A single-phase full converter bridge is connected to the RLE load. The source

voltage is 230 V, 50 Hz. The average load current of 10 A is continuous over the

working range. For R=0.4 ohm and L = 2mH, find the firing angle delay (in

degree) for E=120 V

• 32.12°

• 43.51°

• 53.21°

• 71.21°

A single phase fully controlled bridge rectifier is operated from 240 V, 50 Hz ac mains

with firing angle 30°. Load draws a continuous and ripple free current of 12 A. Then

which of the following is correct

• Average output voltage is 187.12 V

• Rms value of source current is 6 A

• Reactive power drawn from the supply is 1296 kVAR

• Real power drawn from the supply is 3245.4 W

A 230 V, 50 Hz, one-pulse SCR controlled converter has extinction angle β = 200°.

Find the circuit turn-off time

• 10 m-sec

• 0

• 8.9 m-sec

• 5.4 m-sec

Which of the following is a common technique to enhance the performance of gate

drivers?

• Using low power supply voltage

• Increasing the gate resistance

• Adding a bootstrap circuit for high-side drive

• Using a single-ended configuration