Question

A 3-phase full converter delivers a ripple free load current of 10 A with a firing angle delay of 45°. Find the DF (distortion factor).

(a) 1.414

(b) 0

(c) 0.707

(d) 0.569

This question was addressed to me in final exam.

My question is taken from Advance Three Phase Converters in section Converters of Power Electronics

Answer 1

The correct option is (c) 0.707

The explanation is: DF = cosα = cos45 = 0.707

Note that ripple free current does not mean that DF = 0. It means the current is continues in magnitude and direction, current will always contain harmonics (distortions) whether it is rippled or ripple free.