1. A single-phase, voltage source, square wave inverter feeds a pure inductive load. The waveform of the current will be
2. In the sinusoidal pulse-width modulation scheme, if the zero of the triangular wave coincides with the zero of the reference sinusoidal, then the number of pulse per half cycle is
3. In a single-phase full bridge inverter what is the advantages of a unipolar switching over the bipolar switching?
- Apparent doubling of the switching frequency
- elimination of 5th and 7th harmonics
- increase of the fundamental component by a factor of 115 for the same DC input voltage
- none of the above
4. A voltage source inverter is used when source and load inductances are respectively
- small and small
- large and large
- large and small
- small and large
5. For a 1-phase full-bridge inverter fed from 48 V dc and connected to load resistance of 2.4 Ω, the RMS value of fundamental component of output voltage is
- 43.2 V
- 34.4 V
- 21.6 V
- 20 V
6. A voltage source inverter (VSI) is normally employed when
- both source inductance and load inductance are large
- both source inductance and load inductance are small
- source inductance is small and load inductance is large
- source inductance is large and load inductance is small
7. In a single-phase VSI bridge inverter, the load current is Io = 200sin(ωt – 45°) mA. The d.c. supply voltage is 220 V. What is the power drawn from the supply?
- 34.03 W
- 27.25 W
- 19.8 W
- 9.8 W
8. A single-phase full bridge inverter is connected to a load of 2.4 Ω. The d.c. input voltage is 48 V. What is the r.m.s. output at fundamental frequency?
9. A single-phase half-bridge inverter has input voltage of 48 V DC. Inverter is feeding a load of 2.4 Ω. The RMS output voltage at fundamental frequency is
10. Which one of the following statements is correct?
A voltage source inverter is normally employed
- when both the source and load have low values of impedance and reactance respectively.
- when both the source and load have high values of impedance and reactance respectively.
- when the source has high impedance and load has low reactance
- when the source has low impedance and load has high reactance
11. A single-phase inverter has square wave output voltage. What is the percentage of the fifth harmonic component in relation to the fundamental component?
12. Compared to a single-phase half-bridge inverter, the output power of a single-phase full-bridge inverter is higher by a factor of
13. In case of voltage source inverter, free-wheeling can be needed for the load of
- back emf nature
- resistive nature
- capacitive nature
- inductive nature
14. The main application of multilevel inverter is in
- voltage regulator
- synchronous buck converter
- dc motor drive
- reactive power compensation
15. Current source inverters are suitable for supply power to
- RL loads
- Inductive loads
- Capacitive loads
- All loads
16. A current source inverter is obtained by inserting a large
- capacitance in series with dc supply
- inductance in parallel with dc supply
- capacitance in parallel with dc supply
- inductance in series with dc supply
17. A single-phase current source inverter is connected with capacitive load only the waveform of the output voltage across the capacitor for constant source current will be
- step function
- triangular wave
- square wave
- sine wave
18. In 3-phase inverter with 180° conduction mode the number of switches that is on at any instant of time is
19. What is the region of operation of a 3-phase inverter employing sinusoidal PWM when the peak-to-peak values of both the carrier and the modulating waves are made equal?
- six-step operation
- boundary of linear modulation and over modulation
- over modulation
- linear modulation
20. What should be the frequency modulation ratio (mf) for a 3-phase inverter, if the mfth harmonic and its odd multiples are to be suppressed in the line-to-line voltages?
- mf should be odd
- mf should be even
- mf should be an odd multiple of 3
- mf should be an even multiple of 3