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GATE 2017 EE (EE2) – Question 21

Power Electronics · Magnitude and Phase of line current harmonics for uncontrolled and thyristor based converters · 1 mark · Multiple choice

A phase-controlled single-phase full-bridge converter supplies a highly inductive DC load from 230 V, 50 Hz AC. The fundamental frequency of the DC-side voltage ripple in Hz is

  1. 25
  2. 50
  3. 100
  4. 300

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Correct answer: (C) 100

Explanation

A full bridge produces two similar output-voltage pulses in each input cycle. With continuous current in the highly inductive load, the DC-side voltage pattern repeats after half an AC period.

Its ripple fundamental is therefore twice the supply frequency: 2×50=**100 Hz, C**. Firing angle changes the average and ripple amplitudes, while the two-pulse repetition frequency remains 100 Hz.