Power Electronics MCQ Quiz - Multiple Choice Questions & Answers Page 3

21. Double fourier series analysis of PWM is

1. Three dimensional functions
2. One dimensional functions
3. Two dimensional functions
4. All of these

22. During the commutation period in 3 phase converter, overlap time is

1. Dependent on the voltage
2. Dependent on both the load current and load voltage behind the short circuit current
3. Dependent on the load current
4. Independent on both the load current and load voltage

23. For a buck converter to reduce the conduction losses in diode

1. A low on - resistance switch can be added in parallel
2. A high on - resistance switch can be added in series
3. A high on - resistance switch can be added in parallel
4. A low on - resistance switch can be added in series

24. For bidirectional operation of converters

1. A parallel combination of controllable switch and capacitor is used
2. A series combination of controllable switch and a diode is used
3. A parallel combination of controllable switch and a diode is used
4. A series combination of controllable switch and a capacitor is used

25. For similar carrier and modulating signals, the line current used in CSI is

1. Identical to line current in VSI
2. Identical to phase voltage in VSI
3. Identical to line voltage in a VSI
4. Identical to phase voltage in CSI

26. For sweptfrequency measurements, the input impedance of the mismatched transmission line would vary with frequency as the electrical length ofthe transmission line would

1. Remains same with change in frequency
2. Increase with frequency
3. Decrease with frequency
4. Either (a or b)

27. Harmonics in 3 phase inverters can be reduced by using

1. Active filter
2. Both passive and active filters
3. Passive filter
4. None of these

28. In a 3 phaseCSI, if the required line output voltages are balanced and 120 degreeout of phase, then the chopping angles are used to eliminate only theharmonics at frequencies

1. 7
2. 11
3. 5
4. All of these

29. In a load commutated DC - DC chopper, the capacitor has a

1. Symmetric rectangular voltage across itself
2. Symmetric trapezoidal voltage across itself
3. Symmetric triangular voltage across itself
4. Symmetric sinusoidal voltage across itself

30. In a three phase converter, the number of notches per cycle is

1. Three
2. Six
3. One
4. Nine