Solve any four
1(a)
Write short note on thyristors family.
5 M
1(b)
Explain the principle of operation of power MOSFET.
5 M
1(c)
Draw the circuit diagram of any one application using TRIAC & DIAC and compare their V-I characteristics.
5 M
1(d)
State the conditions for getting inversion mode of operation in case of line commutated rectifiers.
5 M
1(e)
Why there is a restriction on the firing angle in case of ac voltage controllers feeding highly inductive load.
5 M
2(a)
Explain the concept of space vector modulation.
5 M
2(b)
Compare the properties of power BJT, power MOSFET and IGBT.
5 M
2(c)
Explain with relevant circuit diagram and waveforms the working of a single phase bidirectional phase control type AC voltage controllers connected to R load and obtain a relationship between the r.m.s. output voltage and the R.M.S. input voltage.
10 M
3(a)
Draw a neat circuit and explain the working of full wave fully controlled 6-pulse 3 ϕ bridge circuit with resistive load. Draw the corresponding input and output voltage waveforms when the firing angle α=90°.
10 M
3(b)
A single phase full wave fully controlled bridge rectifier is operated with an R-L load. Calculate average D.C. output voltage, input power factor, displacement factor and Total Harmonic distortion, if a 50 Hz. Sinusoidal voltage of 220 V. Peak is applied.
10 M
4(a)
Explain with a neat circuit diagram and relevant waveforms, the working of a boost regulator and derive the expression for output voltage, filter capacitance and filter inductance.
10 M
4(b)
Explain dynamic characteristics of SCR with wave forms.
10 M
5(a)
Explain with relevant wave forms any one method to control the magnitude frequency of the output voltage of the single phase inverter.
10 M
5(b)
Explain with circuit diagram and waveforms, three phase bridge inverter for 120 conduction mode.
10 M
Explain the following
6(a)
Basic working principle of Matrix converter.
5 M
6(b)
Any two commutation circuits of SCR.
5 M
6(c)
Comparison of fully controlled and half controlled full wave rectifier with R-L load
5 M
6(d)
Snubber circuit of SCR
5 M
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