Question

Calculate the line voltage for 3-∅ 120° VSI if the value of DC supply is 96 V.

(a) 68.25 V

(b) 67.87 V

(c) 66.25 V

(d) 62.14 V

I got this question at a job interview.

My enquiry is from Solid-State Switching Circuits in division Introduction to Solid-State Switching Circuits of Electric Drives

Answer 1

The correct choice is (b) 67.87 V

Best explanation: The line voltage for 3-∅ 120° VSI is (VDC÷√2)=.707×96=67.87 V. In 3-phase 120° VSI each phase conducts for 120° and only three switches from different phases conduct at a single time.