1: An ideal symmetrical square-wave output contains
15s
Only the fundamental component
Fundamental and even harmonics
Fundamental and odd harmonics
All harmonics with equal amplitudes
2: A full-bridge inverter produces a square-wave output alternating between +200 V and −200 V. Its total RMS output voltage is:
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100 V
200 V
141.4 V
180.1 V
3: Dead time is introduced between the gate signals of the upper and lower switches in the same leg to prevent:
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Reverse load current
Conduction through antiparallel diode
Shoot-through of the DC link
Fundamental output voltage
4: A conventional single-phase half-bridge inverter requires how many controlled switches
10s
2
3
4
1
5: When a single-phase square-wave inverter supplies an RL load, how does the output current change?
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Smoother, with its fundamental leading the voltage fundamental
Square-shaped and in phase with the voltage
Smoother, with its fundamental lagging the voltage fundamental
Square-shaped and leading the voltage
6: In an IGBT half-bridge inverter, which device conducts when Vo > 0 and Io < 0 ? (Take the switch midpoint as the positive output terminal and current towards the load as positive)
20s
Upper IGBT
Lower antiparallel diode
Lower IGBT
Upper antiparallel diode
7: If the fundamental peak voltage of a square wave is 90 V, its third-harmonic peak voltage is
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10 V
(90/π) V
30 V
90 V
8: What are the output voltage levels of a single-phase half-bridge inverter with a total DC-link voltage of 100 V, measured relative to the DC-link midpoint?
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+100 V and −100 V
+100 V and −50 V
+50 V and −50 V
+50 V and −100 V
9: If the fundamental frequency is 50 Hz, the 5th-harmonic frequency is
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100 Hz
150 Hz
200 Hz
250 Hz
10: What are the output voltage levels of a single-phase full-bridge inverter operating in square-wave mode with a DC-link voltage of 100 V?