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GATE 2022 EE – Question 59

Power Electronics · Single and three-phase configuration of uncontrolled rectifiers · 2 marks · Numerical answer

For the ideal AC-DC rectifier circuit shown in the figure below, the load current magnitude is $I_{dc}=15$ A and is ripple free. The thyristors are fired with a delay angle of $45^\circ$. The amplitude of the fundamental component of the source current, in amperes, is ________. (round off to two decimal places)

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Correct answer: 19.00 to 19.20

Explanation

With a ripple-free load current the source current is a square wave of amplitude $I_{dc}$, delayed by the firing angle. Its fundamental has amplitude $\frac{4}{\pi}I_{dc}=\frac{4\times15}{\pi}=19.10$ A, independent of the delay angle.