Wednesday, 13 September 2017

Power Electronics Assignments

Power Electronic
Assignment for Chapter:-1


1.     Define PIV and SUF for rectifier circuits.
2.     Differentiate between holding current and latching current for SCR.
3.     Explain the construction of UJT,and explain its characteristics.
4.     A transformer with line voltage ratio 440V/320V is used for a three phase full wave bridge rectifier. Compute (1) load voltage (2) PIV.
5.     The line voltage on six phase side is 250V for a six phase half wave rectifier. Calculate (1) load current (2) ripple frequency if the load resistance is 10 ohm.
6.     Draw the circuit diagram for three phase half wave rectifier and explain its working with the help of necessary waveforms.
7.     Draw the symbol of IGBT,PUT,GTO,TRIAC.
8.     Explain construction of MCT.
9.     Draw and explain characteristics and construction of IGBT.
10.               State advantages of poly phase rectifier over single phase rectifier.
11.               State different control methods for SCR and explain any one method.
12.                 Explain AC load control using SCR.
13.               Write the name of the device and draw its symbol. 1)SITH 2)RCT.
14.               What is controlled rectifiers? Explain its need.
15.               Explain pulse control using UJT – full wave circuit.
16.               Explain three phase full wave bridge rectifier.
17.               Application of Polyphase Rectifiers.
18.               Define holding and latching current of SCR.
19.               Give the full name and draw the symbol of GTO,MOSFET,TRIAC,MCT.
20.               Why IGBT is most popular in industrial application?
21.               Give the classification of thyristor family.
22.               Explain workin5g of SCR by two transistor circuit analogy.
23.               Derive the expression for Edc and Idc for three phase half wave rectifier.
24.               Derive the expression for Irms for  three phase half wave rectifier.

25.               Derive the expression for  Idc for single phase half wave controlled rectifier.

Assignment for Chapter :-2
1.     Why gate protection is required in SCR?
2.     What is thermal resistance?
3.     State condition for SCR commutation.
4.     Explain why commutation is required for SCR.
5.     What is function of freewheeling diode?
6.     Explain how can you select heat sink for SCR.
7.     Give and explain reasons to protect SCR.
8.     What is snubber circuit and why it is useful?
9.       State different methods of forced communication of SCR and explain any one method.
10.            Draw the thermal equivalent circuit of SCR.
11.            Draw the full protection circuit for SCR combining different protection and explain briefly.
12.            Show the importance of fast acting fuse.
13.            Explain the  turn off characteristics of SCR.
14.            Explain class A commutation method for SCR.
15.            Write short notes on class C and class D type communication.
16.            What is non linear surge absorber and how it can protect against overvoltage.
17.            Explain power ratings of SCR.
18.            Explain thermal resistance with it’s equivalent circuit.
19.            Explain the need of protection of SCR.
20.            Explain surge current and I2t rating of SCR.
21.            State different methods of mounting of SCR. Explain any two.
22.            Explain power rating of SCR.
23.            Draw the wave shape of single phase half wave rectifier
i.                    With R load
ii.                  With RL load
iii.                With RL load and FW diode.


Assignment for Chapter:-3
1.     Write applications of chopper.
2.     Explain John’s chopper.
3.     Explain the working principle of DC chopper.
4.     Draw the circuit for class D chopper and class E chopper.
5.     Give the application of chopper.
6.     Explain the working principle of DC chopper.
7.     Draw the circuit of John’s and Morgan chopper.
8.     Explain constant frequency control method for controlling output voltage of chopper.
9.     Write in short on step up chopper.
10.                        Explain the working of step up chopper with the help of circuit diagram.
11.                        With the help of circuit diagram explain the working of class B chopper.
12.                        Describe Morgan’s chopper with the help  of circuit diagram.
13.                        State basic principle of DC chopper.
14.                        Give classification of chopper and explain class A chopper.
15.                        Draw the circuit of John’s and Morgan chopper.
16.                        Explain use of chopper for speed control of slip ring induction motor.


Assignment for ChapterChapter:-4
1.     Give classification of inverter.
2.     State advantages of PWM(Pulse Width Modulation)method.
3.     State application of cycloconverter.
4.     Draw the waveform of bridge type cycloconverter in which output frequency is one forth of the input frequency.
5.     What is cycloconverter?e State different types of cycloconverter.
6.     Tate various method of pulse width modulation and explain sinusoidal pulse width modulation.
7.     Draw and explain single phase series inverter with its waveform.
8.     Draw the circuit diagram and wave form for single phase to single phase bridge cycloconverter.
9.     What is advantages & disadvantages of pulse width modulation.
10.                        Explain single phase width modulation – SPWM.
11.                        Explain the working principle of cycloconverter.
12.                        Write the application of cycloconverter.
13.                        Draw the circuit of single phase series inverter and explain its working.
14.                        Draw the circuit of center tapped transformer type cycloconverter and explain its working when the load is purely resistive.
15.                        Draw and explain single phase to single phase bridge type cycloconverter for resistive load.
16.                        Give classification of inverter.
17.                        What are application of cycloconverter?
18.                        State basic principle of inverter.
19.                        State advantages and application of inverter.
20.                        Draw the waveform of bridge type cycloconverter in which output frequency is one fourth of the input frequency.
21.                        Draw the circuit and waveform of single phase to single phase bridge cycloconverter with pure resistive load.
22.                        Start various methods of PWM and explain any one.
23.                        Draw and explain single phase parallel inverter with its waveform.
24.                        List the active devices that can be used to build inverter.

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