Question

A single phase full bridge inverter has RLC load with R = 4 Ω, L = 35 mH and C = 155 μF. The dc input voltage is 230 V and the output frequency is 50 Hz. Find the rms value of the fundamental load current.

(a) 28.31 A

(b) 20.02 A

(c) 16.69 A

(d) 26.90 A

I have been asked this question in homework.

Enquiry is from Single Phase VSI-4 in chapter Inverters of Power Electronics

Answer 1

The correct answer is (b) 20.02 A

For explanation: Average value of fundamental output voltage =  4Vs/π = 292.85 V

XL = 2 x 3.14 x 50 x 0.035 = 10.99 Ω

XC = 1/(2 x 3.14 x 50 x 155 x 10^-6) = 20.54 Ω

Z = 10.345 Ω

I = V/Z = 28.31

I(rms) = V/Z√2 = (292.85)/(1.414 x 10.345) = 20.02 A.