GATE 2019 EE – Question 64
A fully-controlled three-phase bridge converter is working from a 415 V, 50 Hz AC supply. It is supplying constant current of 100 A at 400 V to a DC load. Assume large inductive smoothing and neglect overlap. The rms value of the AC line current in amperes (round off to two decimal places) is ________.
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Correct answer: 81.24 to 82.06
Explanation
With a constant DC current, the AC line current of the three-phase bridge is a quasi-square wave with a conduction of $120^\circ$ per half cycle, so its rms value is $I_{line}=\sqrt{\frac23}I_d=0.8165\times100=81.65$ A.