Question

Find the expression for the average value of the output voltage for the below given circuit. Consider the load current to be continuous, firing angle = α, transformer ration 1:1 and Vs = Vm sinωt.

(a) (Vm/π)cosα

(b) (Vm/π)(1+cosα)

(c) (2Vm/π)cosα

(d) (2Vm/π)(1+cosα)

I have been asked this question in final exam.

My query is from Single Phase FW AC-DC-1 in chapter Converters of Power Electronics

Answer 1

Correct option is (c) (2Vm/π)cosα

Best explanation: As the load current is continues, the voltage is positive from α to π and negative from π to π+α and so on. Thus,

Vavg = 1/Period ∫ Vm sin⁡ωt d(ωt)

Where period = π

And the integral runs from α to α+π.