5. a. Explain the working of forward converter and draw the waveforms (6)

0. ۸ fly back converter has the following circuit parameters. Vs-24V, (3)
N1/N2=3,Lin=500: 'H,R=5Q,C=200 F,f40 kHz, vo=5V .Determine the
required duty ratio .b) the minimum,maximum, average values for the line
current.

6. a. Ina CUK converter operating at 50 Hz, ப ‘L2=1mH and The output (6) capacitor is
sufficiently large to yield and essentially constant output voltage. Here Vs—lO V and
the output VD is regulated to be constant at 5V. It is supplying 5W to a load. Assume
ideal components. Calculate the percentage error in assuming a constant voltage
across Cl or in assuming constant currents iL1 and in.

b. Compare the fly-back converter with forward converter. (3)
PART C
7. a. Explain the working principle of a 3-phase inverter in 180°conduction and (12) draw

the gating signals, phase and line voltages and compare with 120° degree conduction
in a three phase inverter

8. a. Describe the working principle of current controlled scheme in voltage source (6)
inverter.

b. Describe the working of a single phase capacitor commutated current source (6)
inverter with pure resistive load.

9. a. Explain the PWM techniques for reduction of harmonic current in inverters. (6)

b. | What are the advantages and disadvantages of current source inverters? (6)