Question

The expression for a step-up/step-down chopper with α as the duty cycle and Vs as the dc input voltage is

(a) Vs/1 – α

(b) α x Vs

(c) Vs (α/1-α)

(d) Vs (α/1+α)

The question was posed to me in an interview.

This interesting question is from Choppers-4 in chapter Choppers of Power Electronics

Answer 1

Right answer is (c) Vs (α/1-α)

To elaborate: A step-up, step-down chopper can behave as a step up chopper for α > 0.5 and step –down chopper for α < 0.5.