Question

A semi-converter circuit gives the following voltage waveform on R load. Find the expression for the average output current with Vs = Vm sinωt and firing angle α

(a) (Vm/Rπ) cosα

(b) (Vm/Rπ) (1+cosα)

(c) (2Vm/Rπ) cosα

(d) (2Vm/Rπ) (1+cosα)

The question was posed to me in a national level competition.

My question is from Single Phase Semi-Converters-1 in portion Converters of Power Electronics

Answer 1

Right choice is (b) (Vm/Rπ) (1+cosα)

The best I can explain: Vo = 1/π ∫ Vm sinωt d(ωt)  Where the integration runs from α to π

Io = Vo/R.