Question

What is the peak value of phase voltage in case of 3-phase VSI with 180° mode. The supply side consists of a constant dc voltage source of Vs.

(a) Vs

(b) 3Vs/2

(c) 2Vs/3

(d) 3Vs

The question was asked by my college professor while I was bunking the class.

Question is taken from 3-Phase Bridge Inverters-2 topic in section Inverters of Power Electronics

Answer 1

The correct answer is (c) 2Vs/3

For explanation I would say: Apply KVL to the equivalent circuit of the inverter by closing and opening the proper switches. The phase voltage is a stepped sine-wave with peak value 2Vs/3.